Abstract: In recent years, wide studies are carried out in usage of isolators in structures and equipment, for the reduction of vibrations transmitted due to earthquakes, machine vibrations and any other minor disturbances. But providing protection against vibrations caused due to blasts still remains challenging due to its high amplitude and very short duration. In this paper, an effort has been put for providing shock isolation for protective structure against dynamic load caused due to Blast, using mechanical springs devoid of damping. Here an analytical study is made to understand the reduction of 10g acceleration to tolerable limit of 0.5g acceleration. Simulations are carried out using ANSYS software to understand the behavior of the spring under varying static and dynamic loads. Transmissibility of the shock from base to top of the spring is also studied using software and results are found to be comparable with the theoretical approach. The results evident that desired transmissibility can be achieved using mechanical springs
1) Friction is the resistance to motion that occurs when two surfaces are in contact with each other. It arises due to irregularities at a microscopic level between the two surfaces.
2) Friction can be classified as static, dynamic, dry, greasy, or viscous depending on whether the surfaces are at rest or in motion and whether a lubricant is present.
3) The laws of static and kinetic friction describe the relationships between friction force and other factors like normal force. The coefficient of friction is the ratio between friction force and normal force.
friction for class 11 CBSE all types of frictionPiyush Sahu
This document discusses friction, including its definition, types (static, kinetic, rolling), and causes. It defines friction as the property that opposes relative motion between two surfaces in contact. There are three types of frictional forces: static frictional force acts between stationary surfaces; kinetic frictional force acts when surfaces are moving and is less than static friction; rolling frictional force opposes rolling motion. The maximum static frictional force is known as limiting frictional force. Friction is caused by intermolecular attraction forces between contacting asperities at a microscopic level, according to modern theory.
This document discusses free vibration in mechanical systems. It defines free vibration as the vibrations of a system that is initially disturbed and then left to vibrate on its own without external forces. Key topics covered include degrees of freedom, natural frequency, types of damping, critical speeds of shafts, and causes of vibration such as unbalance and misalignment. Both undesirable effects and potential useful applications of vibrations are mentioned.
The document discusses vibration dampers and damping. It defines damping as the ability of a vibrating system to dissipate energy, often by converting mechanical energy to heat. There are two main types of damping: material damping from a material's internal friction, and structural damping from friction between assembled parts. Measurement of damping involves analyzing hysteresis loops for materials or conducting vibration tests on structures. Common damping techniques include using viscoelastic dampers, dynamic dampers, and controlling resonance peaks through damping.
This document discusses the concept of a structural fuse as a way to improve the earthquake resistance of buildings. A structural fuse works by concentrating damage in ductile elements called fuses, allowing those elements to yield and dissipate seismic energy from the earthquake. This protects the main structural elements like columns from excessive strain and damage. Specifically, the document focuses on using small vertical fuse bars near the base of a column. By yielding, the fuse bars are designed to absorb energy and allow rotation of the column, reducing fatigue. After an earthquake, only the easily replaceable fuse bars would need repair in order to restore the structure.
This document discusses forced vibration, which occurs when a mechanical system is subjected to a periodic or continuous external force over time. Examples given include a washing machine vibrating due to imbalance, vehicle vibration from road imperfections, and building vibration during earthquakes. Forced vibration can result from constant harmonic excitation, rotating or reciprocating imbalance, excitation of system supports, and the transmission of forces and motion through springs or foundations. Key terms discussed include unbalance, transmissibility, vibration isolation, and amplitude transmissibility.
This document discusses friction and its types. It defines static and kinetic (dynamic) friction. Static friction is what is experienced by a body at rest, while kinetic friction is experienced by a body in motion and is less than static friction. The types of friction are further classified as sliding friction, rolling friction, and pivot friction. Laws related to both static and kinetic friction are provided. The document also discusses journal bearings and turning moment diagrams.
1) Friction is the resistance to motion that occurs when two surfaces are in contact with each other. It arises due to irregularities at a microscopic level between the two surfaces.
2) Friction can be classified as static, dynamic, dry, greasy, or viscous depending on whether the surfaces are at rest or in motion and whether a lubricant is present.
3) The laws of static and kinetic friction describe the relationships between friction force and other factors like normal force. The coefficient of friction is the ratio between friction force and normal force.
friction for class 11 CBSE all types of frictionPiyush Sahu
This document discusses friction, including its definition, types (static, kinetic, rolling), and causes. It defines friction as the property that opposes relative motion between two surfaces in contact. There are three types of frictional forces: static frictional force acts between stationary surfaces; kinetic frictional force acts when surfaces are moving and is less than static friction; rolling frictional force opposes rolling motion. The maximum static frictional force is known as limiting frictional force. Friction is caused by intermolecular attraction forces between contacting asperities at a microscopic level, according to modern theory.
This document discusses free vibration in mechanical systems. It defines free vibration as the vibrations of a system that is initially disturbed and then left to vibrate on its own without external forces. Key topics covered include degrees of freedom, natural frequency, types of damping, critical speeds of shafts, and causes of vibration such as unbalance and misalignment. Both undesirable effects and potential useful applications of vibrations are mentioned.
The document discusses vibration dampers and damping. It defines damping as the ability of a vibrating system to dissipate energy, often by converting mechanical energy to heat. There are two main types of damping: material damping from a material's internal friction, and structural damping from friction between assembled parts. Measurement of damping involves analyzing hysteresis loops for materials or conducting vibration tests on structures. Common damping techniques include using viscoelastic dampers, dynamic dampers, and controlling resonance peaks through damping.
This document discusses the concept of a structural fuse as a way to improve the earthquake resistance of buildings. A structural fuse works by concentrating damage in ductile elements called fuses, allowing those elements to yield and dissipate seismic energy from the earthquake. This protects the main structural elements like columns from excessive strain and damage. Specifically, the document focuses on using small vertical fuse bars near the base of a column. By yielding, the fuse bars are designed to absorb energy and allow rotation of the column, reducing fatigue. After an earthquake, only the easily replaceable fuse bars would need repair in order to restore the structure.
This document discusses forced vibration, which occurs when a mechanical system is subjected to a periodic or continuous external force over time. Examples given include a washing machine vibrating due to imbalance, vehicle vibration from road imperfections, and building vibration during earthquakes. Forced vibration can result from constant harmonic excitation, rotating or reciprocating imbalance, excitation of system supports, and the transmission of forces and motion through springs or foundations. Key terms discussed include unbalance, transmissibility, vibration isolation, and amplitude transmissibility.
This document discusses friction and its types. It defines static and kinetic (dynamic) friction. Static friction is what is experienced by a body at rest, while kinetic friction is experienced by a body in motion and is less than static friction. The types of friction are further classified as sliding friction, rolling friction, and pivot friction. Laws related to both static and kinetic friction are provided. The document also discusses journal bearings and turning moment diagrams.
PPT PRESENTATION ON COULOMB DAMPING AND VISCOUS DAMPINGsrinivas cnu
This document summarizes two types of damping: Coulomb damping and viscous damping. Coulomb damping involves friction between two surfaces, with a friction force proportional to the normal force. Viscous damping dissipates energy through forces proportional to velocity as objects move through fluids. Examples of each type are given, such as friction joints in airplanes for Coulomb damping and fluid films between surfaces for viscous damping. Key differences between the two types are outlined in a table, such as viscous damping force depending on velocity while Coulomb damping force depends on friction coefficients.
#note- it does not covers every thing you might expect. the info provided may not be accurate, images are subjected to copyright and doesn't belong to me. Any image in it has
creative common license.
It covers all Basic concepts of shockers and types with less images but enough to understand the concepts. by Sharishth Singh, linked in profile
www.linkedin.com/in/sharishth-singh-23a311154
Time of creation and upload 6:50 AM, 30 march 2018
made through Microsoft Office.
There are four main types of damping: viscous, Coulomb, material, and magnetic. Viscous damping dissipates energy through movement in a fluid medium. Coulomb damping provides a constant damping force opposite to motion caused by dry or insufficiently lubricated friction surfaces. Material or hysteresis damping results from internal friction as a material deforms. Magnetic damping converts kinetic energy to heat through eddy currents induced in a coil or plate near a magnet during oscillation.
presentation on free and forced vibrationRakshit vadi
This document discusses forced and free vibration. It defines free vibration as vibration of a system when external forces are removed, allowing it to vibrate on its own due to internal elastic forces. Forced vibration occurs when a periodic external force causes vibration, and the system vibrates at the frequency of the applied force rather than its natural frequency. Examples of each type are given. D'Alembert's principle and its application to deriving the natural frequency of vibration of a spring-mass system are also explained. Key equations for natural frequency, time period, and their relationships are provided.
This document summarizes key topics from chapters 1 and 2 of a textbook on seismology by T.K. Datta from IIT. It discusses the interior structure of the Earth, including the crust, mantle, and core. It describes plate tectonics and the three types of plate boundaries. It also summarizes earthquake causes according to the tectonic theory, and the types of seismic waves that propagate during earthquakes, including P, S, L, and R waves. Sample seismic records are shown illustrating different wave patterns.
This presentation focuses on What is an Earthquake,measurement of Earthquake,Terminologies in earthquakes,Seismic waves and its prediction & forecasting.
This document discusses different types of vibrations including longitudinal, transverse, and torsional vibrations. It also discusses free, damped, and forced vibrations. Damping is caused by friction and dissipates the energy of a vibrating system. The type of vibration system depends on the damping factor. Undamped systems have a damping factor of 0, underdamped systems have a damping factor less than 1, critically damped systems have a damping factor of 1, and overdamped systems have a damping factor greater than 1. The amount of damping is important for determining the response of the vibrating system.
This document discusses friction. It defines friction as the tangential forces that develop between two surfaces in contact when one attempts to move relative to the other. These friction forces oppose relative motion. Static friction acts when surfaces are at rest, and can be up to a maximum value determined by the normal force and coefficient of static friction. Kinetic friction acts when surfaces are sliding and depends on the normal force and coefficient of kinetic friction. The coefficients of friction describe the maximum static friction and typical kinetic friction between two surfaces, and are proportional to the normal force but independent of contact area. The document also discusses the angles of friction and provides examples of problems involving dry friction.
Forces can move, stop, or change the direction of motion of an object. Inertia is an object's resistance to changes in its motion due to its mass. Momentum is the quantity of motion an object has, defined as its mass times velocity. Newton's three laws of motion describe the relationship between an object and the forces acting upon it. The law of conservation of momentum states that the total momentum of an isolated system remains constant. Friction opposes motion and can be advantageous or disadvantageous depending on the situation. Uniform circular motion requires a centripetal force directed toward the center of rotation.
Dynamics of Machines- Unit IV-Forced VibrationDr.S.SURESH
This document discusses different types of vibrations including free vibration, forced vibration, and damped vibration. It focuses on forced vibration where a body vibrates under the influence of an external force. Examples given are electrical bells and air compressors. The types of external excitation forces are periodic, impulsive, and random. Equations of motion are provided for forced damped vibration systems. Concepts such as frequency response, phase lag, magnification factor, and vibration isolation are also summarized.
This document discusses the topic of friction. It defines friction as the force that resists the relative motion between two objects in contact. There are different types of friction including dry friction, fluid friction, lubricated friction, skin friction, and internal friction. Static friction acts on objects at rest, while dynamic friction acts on moving objects, with dynamic friction always being less than static friction. The coefficient of friction and angle of friction are also discussed, with the coefficient of friction being the tangent of the angle of friction. Applications of friction are mentioned, including in automobiles, transportation, and households. Measurement devices for friction are also listed.
This document discusses different types of forces. It defines push and pull forces and provides examples. It explains that a force is a push or pull and defines the Newton as the SI unit of force. It discusses that an interaction between two objects results in a force and provides an example of pushing an ice cream cart. It also discusses net force, magnitude and direction of forces. The document further explains how forces can cause motion, change speed or direction of an object. It distinguishes between contact forces like muscular force and friction, and non-contact forces like magnetic and gravitational forces. It defines pressure and its relationship to force and area. It also discusses atmospheric pressure and how it balances pressure inside our bodies.
“Comparative Analysis of Blast Load on Multi Storey R.C.C. Building at Differ...IRJET Journal
This document summarizes a research paper that analyzes the effects of blast loads on multi-story reinforced concrete (RCC) buildings using computer modeling. 32 different blast load cases are modeled using ETABS software, varying the standoff distance (20m and 30m), TNT charge weight (50-300kg), and location of the blast (external walls and internal columns). The response of the building models under blast loading is examined through time history analysis, evaluating story displacement, drift, and shear. The goal is to better understand how RCC buildings respond structurally to blast loads at different locations and intensities.
IRJET- The State of the Art on Analytical Investigation of RCC Viaduct Pi...IRJET Journal
This document discusses analytical investigation of reinforced concrete viaduct pier structures due to air blast loads from explosions. It begins with an introduction to transportation infrastructure like bridges, flyovers and metros that use piers. It then discusses explosion phenomena like deflagration and detonation that generate blast waves. It covers blast loading characteristics like peak pressure, impulse, scaling laws and methods for calculating blast loads. The document aims to understand blast loads to inform the design of pier structures to withstand explosions and reduce casualties.
Development of-new-control-techniques-for-vibration-isolation-of-structures-u...Cemal Ardil
The document discusses the development of new control techniques for vibration isolation of structures using smart materials. It summarizes previous research that showed isolation reduces acceleration and forces in structures but increases sliding displacement at low excitation frequencies. The paper then presents a study of a space frame structure on sliding bearings with a restoring force device. The results show the restoring force device reduces displacement of the structure and peak acceleration, bending moment, and base shear values compared to a structure without the device. The simulation demonstrates the effectiveness of the developed isolation method.
A Review on an Effective Implementation of Particle Impact Damper to Suppress...IRJET Journal
This document provides a review of particle impact damping techniques used to suppress vibrations in various applications. Particle impact damping involves attaching an impact mass containing particles to a vibrating structure. Vibrational energy is dissipated through impacts between the particles and main structure. The review discusses how particle impact dampers have been used effectively in applications like robots, aircraft, bridges, machine tools and other lightly damped structures to reduce undesirable vibrations. It also summarizes several studies that investigated using particle impact damping to improve damping in structures like robot arms, drilling tools, bridge pylons and communication towers. The studies found impact damping can provide effective attenuation of vibrations over a wide range of frequencies and environments.
This document discusses the design of blast resistant structures. It begins by explaining that terrorist attacks involving explosives have increased the need to consider blast loads in building design. The objectives are to explain blast resistant design theories and techniques. It describes the effects of explosions, including shock waves and pressure decay over distance. Design considerations for blast resistant structures include reinforcing steel, concrete strength, and "bomb proof" concrete with steel fibers. The document also discusses reducing blast impacts through increasing stand-off distance from explosions. Both architectural and structural design aspects are important for blast resistance. Structural designs aim to prevent overall collapse and distribute explosion energy without failure.
Analysis of Moment Resisting Reinforced Concrete Frames for Seismic Response ...IRJET Journal
This document discusses the analysis of moment resisting reinforced concrete frames to evaluate the seismic response reduction factor with and without dampers. It first provides background on earthquakes and the need to reduce vibration in structures. It then describes the use of passive energy dissipating devices like viscous and viscoelastic dampers to absorb energy during earthquakes. The study aims to analyze the seismic behavior of a G+8 building model with and without these dampers using software. The results show that when dampers are applied at alternate floors, the maximum displacement is reduced by 42% in one direction and displacement limits specified in codes are not exceeded. Therefore, it can be concluded that dampers improve the seismic performance of structures against earthquakes by increasing stability
Earthquake risks and effective of earthquake load and wind load on behavior ofIAEME Publication
This document discusses shear walls, which provide lateral resistance in buildings. Shear walls are vertical reinforced concrete walls that carry earthquake and wind loads down to the foundation. They are preferred in seismic zones because they perform well, are easy to construct, and help minimize earthquake damage. The document examines the different types of structural failure that can occur due to lateral loads, such as sliding, overturning, and racking deformation. It also outlines the methodology for earthquake-resistant design, which involves ensuring the structure can safely transmit inertia forces through the foundation.
Earthquake risks and effective of earthquake load and wind load on behavior ofIAEME Publication
This document discusses shear walls, which provide lateral resistance in buildings. Shear walls are vertical reinforced concrete walls that carry earthquake and wind loads down to the foundation. They are preferred in seismic zones because they perform well, are easy to construct, and help minimize earthquake damage. The document examines the different types of failures that can occur when a building experiences lateral loads, such as overturning, sliding, and racking. It also outlines the methodology for earthquake-resistant design, which focuses on ensuring adequate lateral load capacity.
Investigating the Effect of Pounding on Seismic Response of Isolated StructuresIJMER
This document summarizes an investigation into the effect of pounding on the seismic response of isolated structures. The study used numerical modeling to analyze the response of a 4-story isolated building with and without pounding. The results showed that pounding can significantly increase floor accelerations, inter-story displacements, and shear forces compared to an isolated building without pounding. Parameters like isolation system stiffness, superstructure stiffness, damping, and the use of impact buffers were also examined. The key finding was that pounding can reduce the effectiveness of seismic isolation in protecting structures and needs to be considered in design.
PPT PRESENTATION ON COULOMB DAMPING AND VISCOUS DAMPINGsrinivas cnu
This document summarizes two types of damping: Coulomb damping and viscous damping. Coulomb damping involves friction between two surfaces, with a friction force proportional to the normal force. Viscous damping dissipates energy through forces proportional to velocity as objects move through fluids. Examples of each type are given, such as friction joints in airplanes for Coulomb damping and fluid films between surfaces for viscous damping. Key differences between the two types are outlined in a table, such as viscous damping force depending on velocity while Coulomb damping force depends on friction coefficients.
#note- it does not covers every thing you might expect. the info provided may not be accurate, images are subjected to copyright and doesn't belong to me. Any image in it has
creative common license.
It covers all Basic concepts of shockers and types with less images but enough to understand the concepts. by Sharishth Singh, linked in profile
www.linkedin.com/in/sharishth-singh-23a311154
Time of creation and upload 6:50 AM, 30 march 2018
made through Microsoft Office.
There are four main types of damping: viscous, Coulomb, material, and magnetic. Viscous damping dissipates energy through movement in a fluid medium. Coulomb damping provides a constant damping force opposite to motion caused by dry or insufficiently lubricated friction surfaces. Material or hysteresis damping results from internal friction as a material deforms. Magnetic damping converts kinetic energy to heat through eddy currents induced in a coil or plate near a magnet during oscillation.
presentation on free and forced vibrationRakshit vadi
This document discusses forced and free vibration. It defines free vibration as vibration of a system when external forces are removed, allowing it to vibrate on its own due to internal elastic forces. Forced vibration occurs when a periodic external force causes vibration, and the system vibrates at the frequency of the applied force rather than its natural frequency. Examples of each type are given. D'Alembert's principle and its application to deriving the natural frequency of vibration of a spring-mass system are also explained. Key equations for natural frequency, time period, and their relationships are provided.
This document summarizes key topics from chapters 1 and 2 of a textbook on seismology by T.K. Datta from IIT. It discusses the interior structure of the Earth, including the crust, mantle, and core. It describes plate tectonics and the three types of plate boundaries. It also summarizes earthquake causes according to the tectonic theory, and the types of seismic waves that propagate during earthquakes, including P, S, L, and R waves. Sample seismic records are shown illustrating different wave patterns.
This presentation focuses on What is an Earthquake,measurement of Earthquake,Terminologies in earthquakes,Seismic waves and its prediction & forecasting.
This document discusses different types of vibrations including longitudinal, transverse, and torsional vibrations. It also discusses free, damped, and forced vibrations. Damping is caused by friction and dissipates the energy of a vibrating system. The type of vibration system depends on the damping factor. Undamped systems have a damping factor of 0, underdamped systems have a damping factor less than 1, critically damped systems have a damping factor of 1, and overdamped systems have a damping factor greater than 1. The amount of damping is important for determining the response of the vibrating system.
This document discusses friction. It defines friction as the tangential forces that develop between two surfaces in contact when one attempts to move relative to the other. These friction forces oppose relative motion. Static friction acts when surfaces are at rest, and can be up to a maximum value determined by the normal force and coefficient of static friction. Kinetic friction acts when surfaces are sliding and depends on the normal force and coefficient of kinetic friction. The coefficients of friction describe the maximum static friction and typical kinetic friction between two surfaces, and are proportional to the normal force but independent of contact area. The document also discusses the angles of friction and provides examples of problems involving dry friction.
Forces can move, stop, or change the direction of motion of an object. Inertia is an object's resistance to changes in its motion due to its mass. Momentum is the quantity of motion an object has, defined as its mass times velocity. Newton's three laws of motion describe the relationship between an object and the forces acting upon it. The law of conservation of momentum states that the total momentum of an isolated system remains constant. Friction opposes motion and can be advantageous or disadvantageous depending on the situation. Uniform circular motion requires a centripetal force directed toward the center of rotation.
Dynamics of Machines- Unit IV-Forced VibrationDr.S.SURESH
This document discusses different types of vibrations including free vibration, forced vibration, and damped vibration. It focuses on forced vibration where a body vibrates under the influence of an external force. Examples given are electrical bells and air compressors. The types of external excitation forces are periodic, impulsive, and random. Equations of motion are provided for forced damped vibration systems. Concepts such as frequency response, phase lag, magnification factor, and vibration isolation are also summarized.
This document discusses the topic of friction. It defines friction as the force that resists the relative motion between two objects in contact. There are different types of friction including dry friction, fluid friction, lubricated friction, skin friction, and internal friction. Static friction acts on objects at rest, while dynamic friction acts on moving objects, with dynamic friction always being less than static friction. The coefficient of friction and angle of friction are also discussed, with the coefficient of friction being the tangent of the angle of friction. Applications of friction are mentioned, including in automobiles, transportation, and households. Measurement devices for friction are also listed.
This document discusses different types of forces. It defines push and pull forces and provides examples. It explains that a force is a push or pull and defines the Newton as the SI unit of force. It discusses that an interaction between two objects results in a force and provides an example of pushing an ice cream cart. It also discusses net force, magnitude and direction of forces. The document further explains how forces can cause motion, change speed or direction of an object. It distinguishes between contact forces like muscular force and friction, and non-contact forces like magnetic and gravitational forces. It defines pressure and its relationship to force and area. It also discusses atmospheric pressure and how it balances pressure inside our bodies.
“Comparative Analysis of Blast Load on Multi Storey R.C.C. Building at Differ...IRJET Journal
This document summarizes a research paper that analyzes the effects of blast loads on multi-story reinforced concrete (RCC) buildings using computer modeling. 32 different blast load cases are modeled using ETABS software, varying the standoff distance (20m and 30m), TNT charge weight (50-300kg), and location of the blast (external walls and internal columns). The response of the building models under blast loading is examined through time history analysis, evaluating story displacement, drift, and shear. The goal is to better understand how RCC buildings respond structurally to blast loads at different locations and intensities.
IRJET- The State of the Art on Analytical Investigation of RCC Viaduct Pi...IRJET Journal
This document discusses analytical investigation of reinforced concrete viaduct pier structures due to air blast loads from explosions. It begins with an introduction to transportation infrastructure like bridges, flyovers and metros that use piers. It then discusses explosion phenomena like deflagration and detonation that generate blast waves. It covers blast loading characteristics like peak pressure, impulse, scaling laws and methods for calculating blast loads. The document aims to understand blast loads to inform the design of pier structures to withstand explosions and reduce casualties.
Development of-new-control-techniques-for-vibration-isolation-of-structures-u...Cemal Ardil
The document discusses the development of new control techniques for vibration isolation of structures using smart materials. It summarizes previous research that showed isolation reduces acceleration and forces in structures but increases sliding displacement at low excitation frequencies. The paper then presents a study of a space frame structure on sliding bearings with a restoring force device. The results show the restoring force device reduces displacement of the structure and peak acceleration, bending moment, and base shear values compared to a structure without the device. The simulation demonstrates the effectiveness of the developed isolation method.
A Review on an Effective Implementation of Particle Impact Damper to Suppress...IRJET Journal
This document provides a review of particle impact damping techniques used to suppress vibrations in various applications. Particle impact damping involves attaching an impact mass containing particles to a vibrating structure. Vibrational energy is dissipated through impacts between the particles and main structure. The review discusses how particle impact dampers have been used effectively in applications like robots, aircraft, bridges, machine tools and other lightly damped structures to reduce undesirable vibrations. It also summarizes several studies that investigated using particle impact damping to improve damping in structures like robot arms, drilling tools, bridge pylons and communication towers. The studies found impact damping can provide effective attenuation of vibrations over a wide range of frequencies and environments.
This document discusses the design of blast resistant structures. It begins by explaining that terrorist attacks involving explosives have increased the need to consider blast loads in building design. The objectives are to explain blast resistant design theories and techniques. It describes the effects of explosions, including shock waves and pressure decay over distance. Design considerations for blast resistant structures include reinforcing steel, concrete strength, and "bomb proof" concrete with steel fibers. The document also discusses reducing blast impacts through increasing stand-off distance from explosions. Both architectural and structural design aspects are important for blast resistance. Structural designs aim to prevent overall collapse and distribute explosion energy without failure.
Analysis of Moment Resisting Reinforced Concrete Frames for Seismic Response ...IRJET Journal
This document discusses the analysis of moment resisting reinforced concrete frames to evaluate the seismic response reduction factor with and without dampers. It first provides background on earthquakes and the need to reduce vibration in structures. It then describes the use of passive energy dissipating devices like viscous and viscoelastic dampers to absorb energy during earthquakes. The study aims to analyze the seismic behavior of a G+8 building model with and without these dampers using software. The results show that when dampers are applied at alternate floors, the maximum displacement is reduced by 42% in one direction and displacement limits specified in codes are not exceeded. Therefore, it can be concluded that dampers improve the seismic performance of structures against earthquakes by increasing stability
Earthquake risks and effective of earthquake load and wind load on behavior ofIAEME Publication
This document discusses shear walls, which provide lateral resistance in buildings. Shear walls are vertical reinforced concrete walls that carry earthquake and wind loads down to the foundation. They are preferred in seismic zones because they perform well, are easy to construct, and help minimize earthquake damage. The document examines the different types of structural failure that can occur due to lateral loads, such as sliding, overturning, and racking deformation. It also outlines the methodology for earthquake-resistant design, which involves ensuring the structure can safely transmit inertia forces through the foundation.
Earthquake risks and effective of earthquake load and wind load on behavior ofIAEME Publication
This document discusses shear walls, which provide lateral resistance in buildings. Shear walls are vertical reinforced concrete walls that carry earthquake and wind loads down to the foundation. They are preferred in seismic zones because they perform well, are easy to construct, and help minimize earthquake damage. The document examines the different types of failures that can occur when a building experiences lateral loads, such as overturning, sliding, and racking. It also outlines the methodology for earthquake-resistant design, which focuses on ensuring adequate lateral load capacity.
Investigating the Effect of Pounding on Seismic Response of Isolated StructuresIJMER
This document summarizes an investigation into the effect of pounding on the seismic response of isolated structures. The study used numerical modeling to analyze the response of a 4-story isolated building with and without pounding. The results showed that pounding can significantly increase floor accelerations, inter-story displacements, and shear forces compared to an isolated building without pounding. Parameters like isolation system stiffness, superstructure stiffness, damping, and the use of impact buffers were also examined. The key finding was that pounding can reduce the effectiveness of seismic isolation in protecting structures and needs to be considered in design.
IRJET-The Study of Effect of Blast Load on Multi-Storey Building by using Tim...IRJET Journal
This document discusses a study on the effect of blast loads on multi-storey buildings using time history analysis. A G+4 storey reinforced concrete building is subjected to blast loads from charges weighing 100, 300, and 500kg placed at standoff distances of 30, 40, and 50m. Nonlinear time history analysis is carried out using ETABS 2016 software. The response of the structure is examined in terms of displacement, velocity, acceleration, storey drift, beam forces, column forces, and storey displacement. The results show that when the blast source is closer and the charge weight is higher, the building response is more critical.
This document discusses guidelines for properly using blasting seismographs to measure ground vibrations and airblast from explosive blasting. It recommends that seismographs be deployed outside of structures to be monitored, with geophones buried several inches underground to properly couple with the ground. Guidelines are provided by the International Society of Explosives Engineers on seismograph settings like data range, sampling rate, and trigger levels to ensure accurate recording of blast vibrations. Proper use of seismographs is important for compliance with regulations and evaluating blast performance.
Analysis of blast loading effect on high rise buildingsAlexander Decker
This document analyzes the effect of blast loading on high-rise buildings. It describes modeling a 30-story reinforced concrete building in SAP2000 and subjecting it to blast loads from charges of 800 and 1600 pounds of TNT at distances of 5 and 10 meters. The results show that as the standoff distance increases, inter-story drift decreases, and as the explosive weight increases, inter-story drift increases. The maximum inter-story drift of 16.5 mm occurred for an irregular frame model with a charge weight of 1600 pounds at a distance of 5 meters.
Analysis of blast loading effect on high rise buildingsAlexander Decker
This document analyzes the effects of blast loading on high-rise buildings. It describes modeling a 30-story reinforced concrete building in SAP2000 and subjecting it to blast loads from charges of 800 and 1600 pounds of TNT at distances of 5 and 10 meters. The results show maximum inter-story drift occurs on the first story due to its proximity to the blast. Regular infill frames performed best by exhibiting the lowest drift values, while irregular frames performed worst. Increasing standoff distance and decreasing charge weight both reduced structural response based on inter-story drift values.
The document discusses using linear fluid viscous dampers to dissipate seismic energy in steel structures, summarizing how the dampers work by resisting force through piston movement in viscous fluid according to velocity. A study is presented analyzing the seismic response of a 12-story steel building with diagonal fluid viscous dampers subjected to earthquake accelerations, finding the dampers significantly improve the structure's dissipative capacity and reduce necessary steel quantities.
This document is a project report on the effects of earthquakes on foundations and seismic design. It discusses various types of seismic waves like P, S, Love, and Rayleigh waves. It also covers causes of earthquakes, seismic loads on structures, risk zones, and response of different building systems. The report will analyze how soil-structure interaction affects seismic response and discuss retrofitting techniques to improve building safety during earthquakes. It aims to study how new technologies can significantly reduce energy losses and property damage from earthquakes.
This document discusses base isolation as a technique for earthquake engineering. Base isolation involves separating the structure from its foundation using flexible isolators, which increases the fundamental period of the structure and provides damping. This reduces accelerations, drifts, and seismic impacts on the structure. The document provides an overview of base isolation methodology, purposes of base isolation like shifting the structure's period away from ground motion frequencies, and common base isolation devices like elastomeric bearings.
Design and Analysis of a Multistory Reinforced Concrete Frame in Different Se...ijtsrd
This study work focuses on the analysis of a structural system to determine the deformations and comparison of steel quantity of seismic zones. In this study, we have taken G 12 multi storied RC moment resisting framed structure building with the shear wall by analyzing the structure for gravity load, wind load and seismic loads for different cities. By Selecting four different cities on the basis of seismic zones zone II, zone III, zone IV, zone V and also considering that the basic wind speed. We have mainly focus on the structural system to determine the deformations and also forces induced by applied loads or ground excitation is an essential step in the design of a structure to resist earthquake. The analysis and design for all the cities are carried out using STAAD Pro' and STAAD Foundation' software which are industry standard software the world over. The wind resistant design is carried out as per IS 875 Part 3 1987 and the earthquake resistant design is carried out as per IS 1893 Part 1 2002. Analysis and design of beams, columns and shear wall have been done in STAAD Pro and the foundation is done in STAAD Foundation. We have also checked the design of some beams, columns, and footings manually and find correct. Design of RCC slabs is carried out manually for which an excel sheet is developed for working out moment coefficients for different edge conditions as per IS code. In this study work, we design and analyze a reinforced concrete frame structure in various seismic zones and we observing the variation in the behavior of the structure in various loading conditions. Priyatam Kumar | Vikash Kumar Singh "Design and Analysis of a Multistory Reinforced Concrete Frame in Different Seismic Zone" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26688.pdfPaper URL: https://www.ijtsrd.com/engineering/civil-engineering/26688/design-and-analysis-of-a-multistory-reinforced-concrete-frame-in-different-seismic-zone/priyatam-kumar
A Review on Blast Analysis of Reinforced Concrete Viaduct Pier StructuresIRJET Journal
The document discusses blast analysis of reinforced concrete viaduct pier structures. It begins with an introduction discussing the increasing population leading to more infrastructure development like bridges and viaducts using reinforced concrete piers. It then discusses how explosions can occur near these piers from accidents or terrorism, potentially causing structural failure and casualties. The document reviews explosion types, how blast loads are predicted and modeled, literature on analyzing reinforced concrete structures under blast loading, and methods to improve blast resistance of structures.
This document analyzes the response of different building models subjected to blast loads using ETABS software. A 12-story building is analyzed for 4 cases with different explosive charge weights (100kg and 200kg) and standoff distances (20m and 40m). Blast parameters are calculated using code standards. Four building models are then analyzed - a normal model, and models with increased member sizes, added shear walls, and added bracing. Storey displacement and drift are compared to determine the most blast resistant model.
IRJET- Seismic Analysis and Retrofitting of Reinforced Concrete Building ...IRJET Journal
This document summarizes a research project that analyzed and retrofitted a reinforced concrete building in Indian Seismic Zone V. The researchers modeled an 8-story reinforced concrete building using ETABS software and performed seismic analysis on both the original fixed base building and a version with lead rubber bearings added at the base for base isolation. Their objectives were to compare story drifts, base shear, story shear, and mode shapes between the two buildings when subjected to the 1940 El Centro earthquake record. Their results aimed to demonstrate that base isolation using lead rubber bearings can effectively reduce seismic demands on the building and improve earthquake resistance for new and existing structures.
Drying of agricultural products using forced convection indirect solar dryerIRJESJOURNAL
Abstract:- Drying of three agricultural products namely potato slices, onion slices and whole grapes was done using an indigenously designed and fabricated forced convection indirect solar dryer and under open sunlight. The diurnal variation of temperature, relative humidity in the solar dryer was also compared with the ambient temperature and relative humidity during March and April 2017 for all the three products. The study showed increase of temperature and lower humidity inside the drying chamber at different time interval. Hourly moisture loss for all the three agricultural products in the drying chamber and open sun drying was also compared and the percentage of moisture loss in the drying chamber was found to be higher compared to open sun drying for all the products. The mass of water removed for all the three products in the drying chamber was also found to be higher than the open sun drying. Results of the study showed that forced convection indirect solar dryer is better than the open sun drying method for drying the agricultural products more efficiently.
The Problems of Constructing Optimal Onboard Colored RGB Depicting UAV SystemsIRJESJOURNAL
Abstract:-The problems of constructing optimal adaptive onboard color RGB depictingUAV systems have been analyzed. The problem of optimal formation of color signals of RGB color system has been formulated and solved by implementing the adaptive flight mode of UAVs containing an onboard imaging system. An adaptive UAV mode with an imaging system on board is proposed, which consists of adaptive changes in flight altitude depending on the wavelength of the received color signal. As a result of the optimization of the proposed operating mode of the UAV imaging system, an analytic formula for adaptive device control has been obtained. Recommendations have been given on the practical implementation of the proposed method.
Flexible Design Processes to Reduce the Early Obsolescence of BuildingsIRJESJOURNAL
Abstract:- This work intends to analyze the processes of flexibility to improve the adaptability to the users and to define some strategies to delay building obsolescence. Some approaches that address the architectural flexibility processes are studied to understand the rapid transformation of user lifestyles and changes in needs and performance building requirements. Obsolescence is often characterized by the lack of flexibility in the structure and walls, as well as services that change rapidly according to the different uses of buildings. This poses a threat to the built environment, since a large number of buildings are demolished having still years of useful life. In this way, different types of obsolescence are analyzed, focusing on some structural, economic, functional and social aspects of the construction and the use of buildings, seeking the capacity to design and produce adaptive buildings that are more resilient to obsolescence. Thus, some concepts of flexibility and flexible process are presented to promote adaptability in buildings. However, flexibility is a complex process, a long way to achieve adaptability to the built environment and the changing needs of users. The method used in this analysis takes into account the diversity of the design process, making some considerations about the interrelation of the social, functional and technical aspects. Finally, some conclusions about the design methods faced by a flexible approach process can lead to more useful and adaptable spaces for future transformations in order to extend the life cycle and prevent early obsolescence of buildings.
Study on Performance Enhancement of Solar Ejector Cooling SystemIRJESJOURNAL
Abstract: Cooling sector is dominating by vapor compression cooling sector which uses refrigerant which are harmful to environment. The solar ejector cooling system is alternative for vapor compression cycle which uses solar energy to give heat to the generator, which is a viable method for heat generation. The solar ejector cooling system not only fulfills cooling requirement but also helps in energy conservation and protection of environment. It reduces the generator work and decrease the throttling losses. Maintenance requirement and cost is low for ejector cooling system .In this paper, theoretically study is done on enhancement of the performance of solar ejector cooling system. Various system configuration are presented with detailed design. This system still needed a lot of research work to make it alternative for vapor compression cycle based cooling system completely.
Flight Safety Case Study: Adi Sucipto Airport Jogjakarta - IndonesiaIRJESJOURNAL
Abstract: Adi Sucipto Airport-Jogyakarta is an airport with enclave civil status or as TNI-AU airbase (civilian airport within the military area) has limited infrastructure with Azimuth Runway 09-27, has no RESA (Runway End Safety Area). The calculation results using Acceptable Safety Level (ASL) standard 1 x 10-7 shows that the probability of accident risk at wet runway condition is greater than in dry condition. Runway Excursion occurs at the airport, especially when the runway is wet and overrun due to hydroplaning and the plane deviates from the center of runway as well as the aircraft wheels are in contact with ground or obstacle surface outside the runway. It means the thicker layer of water above the runway will cause increased risk of accidents on the runway. This is why standing water should be immediately removed from the runway as quickly as possible. Mitigation efforts need to be done simultaneously with recovery by adding RESA and other preventive efforts in order to water patch and standing water does not exceed 2 mm and apply the mandatory of SOP consistently at the airport.
A Review of Severe Plastic DeformationIRJESJOURNAL
ABSTRACT: This article reviews about Ultrafine grained (UFG) materials processed by Severe Plastic
Deformation. From the period of 1950’s, the researchers made a fountain stone for this technique. Over the last
decades, this SPD technique experienced an enormous growth among the research field. There was a
development of different methods of SPD, production of various materials by SPD with improved and
interesting results based on our requirement. Moreover, different post processing techniques will also help to
enhance the property of the SPD processed material. This paper reviews the overall development of this
technique, various methods of SPD, discussed about the enhancement of the properties and finally concluded
with some specific challenges and issues faced by the modern researchers. It may be helpful to those who wants
specialise in bulk nanomaterials produced by SPD.
Annealing Response of Aluminum Alloy AA6014 Processed By Severe Plastic Defor...IRJESJOURNAL
Abstract: In this paper the study of micro structural stability during annealing with respect to time of conventionally grains (CG) and ultrafine-grained (UFG) of Aluminum AA6014 i s carried out. It has been observed that, the effect of the second phase magnesium-silicon particles in the CG and UFG AA6014 samples leads to a rapid hardness which increases from 40HV10 to 70HV10 within 7 days. Artificial aging shows that the material hardness even increased after 20 hours of annealing at 180°C. In total 30 hours of annealing, the hardness arrives at its maximum and then reduces due to the formation of Mg2Si precipitates, which rise in size and change their coherency. The precipitates cannot efficiently pin the dislocations and act as barriers to the dislocation motion which indicate an overall decrease in the hardness. It also has been found that the ultrafinegrained AA6014 alloy loses its thermal stability at approximately 200°C and recrystallized at 300°C. Thermal stability is strongly dependent on the material purity, second phase particles and/or oxide particles which may break up during rolling and lead to some dispersion strengthening.
Evaluation of Thresholding Based Noncontact Respiration Rate Monitoring using...IRJESJOURNAL
Abstract: - A noncontact method for respiration rate monitoring using thermal imaging was developed and evaluated. Algorithms to capture images, detect the location of the face, locate the corners of the eyes from the detected face and thereafter locate the tip of the nose in each image were developed. The amount of emitted infrared radiation was then determined from the detected tip of the nose. Signal processing techniques were then utilised to obtain the respiration rate in real-time. The method was evaluated on 6 enrolled subjects after obtaining all ethical approvals. The evaluations were conducted against two existing contact based methods; thoracic and abdominal bands. Results showed a correlation coefficient of 0.9974 to 0.9999 depending on the location of the ROI relative to the detected tip of the nose. The main contributions of the work was the successful development and evaluation of the facial features tracking algorithms in thermal imagining, the evaluation of thermal imaging as a technology for respiration monitoring in a hospital environment against existing respiration monitoring systems as well as the real time nature of the method where the frame processing time was 40 ms from capture to respiration feature plotting.
Correlation of True Boiling Point of Crude OilIRJESJOURNAL
Abstract :- The knowledge of the crude boiling point is very important for the refining process design and optimization. In this project the aim is to find the correlation of true boiling points. The study will be very useful in crude transportation and downstream operations. Correlation is tried to obtain by testing a number of crude oil samples from heavy to light. The comparisons of boiling point of different crude samples obtained is tried to compare with already existing correlations. Framol, Destmol and Riazi’s, these three correlation models have taken. The result showed that comparison of three correlation models and which is more accurate.
Combined Geophysical And Geotechnical Techniques For Assessment Of Foundation...IRJESJOURNAL
Abstract: This study was carried out to assess the subsurface conditions around the school of technology complex in Lagos State Polytechnic, Ikorodu, using integrated geophysical and geotechnical techniques. The site lies within the Sedimentary terrain of southwestern Nigeria. Allied Ohmega Resistivity meter was used for data collection of 1-D and 2-D resistivitymeasurement while WinResist software and Dipro software were used for the processing respectively.The results of the vertical electrical sounding indicate that the depth to basement values ranges between 27.6 and 39.5m. The 2D resistivitysurvey has provided valuable information on the lateral and vertical variation of the layer competent for erecting foundation of engineering structures. The CPT probed an average depth of 4.8m and has identified material of very high shear strength associated with dense sand materials. The correlation of the three techniques used revealed similar soil layering consisting of topsoilsandy clay, coarse sand and sand.A mechanically stable coarse sand material was discovered as weathered layer which indicates high load bearing capacity suitable for foundation in the area and can support massive structures.
Abstract:- research stands out because it is provided by the model of Al-Mobaideen (2009) critics to analyze for the governance of information and communications technology (ICT) at the National University of Chimborazo factors which raises the factors such as: strategies and policies, infrastructure and networks, financing and sustainability, and institutional culture that should be taken into account if desired govern the successful integration of ICT in the school. The study is exploratory, the almost total lack of previous studies on Governance of ICT integration at the University. It is concluded that there is a set of organizations with addresses IT markedly different roles in their duties with regard to its orientation to administrative, academic and research. The University has failed to define the strategic role of ICT in their academic, because there is no objective referred to IT academia in 2013-2016 pedi, but also because there is not a pedi-oriented IT the formation. The limited effectiveness of IT organizations in academic activities is provided by the low rate of use of educationalplatformsb_learning.
Gobernanzade las TIC en la Educacion SuperiorIRJESJOURNAL
Abstract:-Se destaca la investigación debido a que se da a conocer mediante el modelo de Al-Mobaideen (2009) los factores críticos a analizar para la gobernanza de las Tecnologías de la información y la Comunicación (TIC) en la Universidad Nacional de Chimborazo donde plantea los factores como:estrategias y políticas, infraestructura y redes, financiación y sostenibilidad, y cultura institucional, que se debe tomar en cuenta si se desea gobernar la integración exitosa de las TIC en la institución educativa. El estudio es exploratoria, por la poca presencia de estudios previos sobre Gobernanza de la integración de las TIC en la Universidad. Se concluye que existe un conjunto de organismos con direcciones de TI con roles notoriamente diferenciados en sus funciones con respecto a su orientación a procesos administrativos, académicos y de investigación. La Universidad no ha logrado definir el rol estratégico de las TIC en su desarrollo académico, porque no existe ningún objetivo referido a TI para el ámbito académico en el PEDI 2013-2016, sino porque además, no se cuenta con un PEDI de TI orientado a la formación. La poca eficacia de los organismos de TI en actividades académicas se da a conocer por la baja tasa de uso de plataformas educativas b_learning.
The Analysis and Perspective on Development of Chinese Automotive Heavy-duty ...IRJESJOURNAL
Abstract: In recent years, under the influence of both China's domestic market demand and emissions standard improvement, Chinese manufacturers put great effort on the research and design of automotive heavy-duty diesel engine. This paper analyzes the technical parameters of heavy duty diesel engine in 11 / 13L displacement section and introduces its performance. At the same time, combined with the development of foreign heavy-duty diesel engine, the future development direction of Chinese heavy-duty diesel engine is forecasted.
Research on The Bottom Software of Electronic Control System In Automobile El...IRJESJOURNAL
Abstract: With the development of science and technology, car replacement faster and faster. The development of the automotive industry has a contradiction, on the one hand, the speed of upgrading the car technology can not keep up with the speed of the performance requirements of the car, on the other hand, the country's automobile exhaust emission standards become more stringent. In addition, the depletion of oil resources led to the rise in gasoline prices, the traditional car is facing a crisis. Considering the situation of gas fuel resource structure and supply situation in China, it is feasible to promote gas fuel engine[1].However, the pollution caused by the car has become one of the major pollution sources in the urban environment and the atmospheric environment, and this trend continues to deteriorate[2].Therefore, alternative energy vehicles and hybrid cars is the main direction of development, and any improvement in the car will be car electronics and software replacement for the premise. On the one hand, natural gas as an alternative to gasoline, with its low prices, excellent combustion emissions, the relative sustainable development and other characteristics of more and more car manufacturers favor;On the other hand, the mainstream of the automotive electronic control unit ECU software development to AUTOSAR structure, low power consumption, functional safety for the development direction. Based on the actual development of natural gas engine control unit, the structure and function of ECU software are studied with reference to AUTOSAR software design standard. This paper studies the structure of the application of the software layer of the electronic control system and the main control strategy under the various conditions of the structure, and puts forward the underlying software resources needed by the application layer software. This paper analyzes the internal and peripheral resources of Infineon XC2785x microcontroller and designs hardware abstraction layer software and ECU abstraction layer software. The current characteristics of the jet valve driven by the natural gas multi-point injection engine were investigated. Automotive electronics technology has been widely used in modern vehicles which, and gradually become the development of new models, improve the performance of the key technical factors[3] .
Evaluation of Specialized Virtual Health Libraries in Scholar Education Evalu...IRJESJOURNAL
Abstract:- The aim is to evaluate the impact on academic training with specialized virtual health libraries (databases and catalogs) available in Institutions of Scholar Education, because there is uncertainty about the appropriate use of these libraries. The research was conducted on the databases available on 2 universities during the academic period August 2015 - February 2016. Using criteria and indicators for evaluating virtual libraries, model quality of university libraries based on fuzzy techniques, Bibliometric and criteria for virtual libraries in health. The study had the participation of 188 students from two universities or groups. The research reveals that for the first group and the second group almost always (60.45%) find the information, the (57.2%) have relevance to the topic, access (45.8%) once a month, and Elseiver and BiblioMedica are the most commonly used, however, mostly ie (78.55%) use traditional libraries versus (58.2%) which are virtual. Descriptive analysis was performed using the software SPSSv20. This experience allows us to confirm that the use of libraries contributes discreetly in academic education, therefore, it requires training plans, reference guides, strengthen the socialization of this resource, free access from anywhere.
Linking Ab Initio-Calphad for the Assessment of the AluminiumLutetium SystemIRJESJOURNAL
Abstract: First-principles calculations within density functional theory (DFT) were used to investigate intermetallics in the Al-Lu system at 0 K. The five compounds of the system were investigated in their observed experimental structures. Thermodynamic modelling of the Au–Lu system was carried out by means of the CALPHAD (calculation of phase diagrams) method. The liquid phase and the intermetallic compounds Al3Lu, Al2Lu, AlLu, Al2Lu3 and AlLu2 are taken into consideration in this optimization. The substitutional solution model was used to describe the liquid phase. The five compounds are treated as stoichiometric phases. The enthalpies of formation of the compounds were found by the ab initio calculations and used in the optimization of the phase diagram.
Thermodynamic Assessment (Suggestions) Of the Gold-Rubidium SystemIRJESJOURNAL
Abstract: Thermodynamic modellings of the Au–Rb system was carried out by means of the CALPHAD (calculation of phase diagrams) method. The liquid phase and the intermetallic compounds Au5Rb, Au2Rb, AuRb and Au7Rb3 and Au3Rb2 (new compounds) in addition to the compound AuRb2 (suspected compound) are taken into consideration in this optimization. The substitutional solution model was used to describe the liquid phase. The six compounds are treated as stoichiometric phases. The enthalpies of formation used in these optimizations were calculated within ab-initio method in precedent work
Elisa Test for Determination of Grapevine Viral Infection in Rahovec, KosovoIRJESJOURNAL
Abstract: Vineyard in Kosovo is estimated to have a great economic potential. There are thousands of hectares of vineyards that contribute to the economic potential of Rahovec by expanding the cultivation area year by year. The vines are affected by a number of viral diseases or pathologies similar to them, which significantly have an impact against the plant life and their production. Therefore, this study was conducted in several farms in Rahovec to determine whether there is a presence of viral infection in the vines. Application of Das-Elisa, Protein A-DAS and Antigen Direct Binding - DASI verified the final identification of viral infection in the collected material. The yellow colour reaction shown on the plate showed the positive result of the Elisa assay for viruses GFLV, ArMV, GLRaV-1, GLRaV-2, GLRaV-3, GVA and GVB in varieties Vranac, Smederevka, Prokup, Afuzali, Grocaka, Demir Kapi, Plovdina, Melika, Zhillavka. The use of specific antibodies will enable the examination of viral diseases in plant materials collected from vineyards and will be oriented to their phytosanitary status.
Abstract. Ensuring of permanent and continuous working process of oil-gas and field equipment alongside with the other factors, depends also on reliability of sealing units. A problem of deterioration modeling of a sealing element of a packer including into an oil field equipment complex is considered in this paper.
Determining Loss of Liquid from Different Types of Mud by Various Addictives ...IRJESJOURNAL
Abstract :- Filtration is used in many industries to separate water from the solid. It is important to find fluid loss in drilling, cementing, fracturing, and almost every other type of downhole treatment design. The filter cake characterization is very essential for well selection of drilling fluid problems and formation damage. Therefore this study is taken up to experimentally investigate the effect of different concentrations of CMC, Starch, Wood fibers, Soda ash, Caustic soda, Bentonite and Barite on filtration loss and formation damages. Three different samples are used in this study at different concentration and a comparison is made. Although the discussion presented here is confined to fluid loss during drilling. Water-based drilling mud’s including Bentonite is wellknown and is being widely used in the petroleum industry. Among the important functions of water-based drilling fluid were to form filter cake on the wall of the well bore, prevent water leakage, and maintain the stability of the well wall. The properties of the water-based drilling fluid, such as the rheology and filtration loss, are affected by the fluid loss additive. Polymers, which are nontoxic, degradable, and environment friendly, are the best choice to be used as drilling fluids additives.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
artificial intelligence and data science contents.pptxGauravCar
What is artificial intelligence? Artificial intelligence is the ability of a computer or computer-controlled robot to perform tasks that are commonly associated with the intellectual processes characteristic of humans, such as the ability to reason.
› ...
Artificial intelligence (AI) | Definitio
Applications of artificial Intelligence in Mechanical Engineering.pdfAtif Razi
Historically, mechanical engineering has relied heavily on human expertise and empirical methods to solve complex problems. With the introduction of computer-aided design (CAD) and finite element analysis (FEA), the field took its first steps towards digitization. These tools allowed engineers to simulate and analyze mechanical systems with greater accuracy and efficiency. However, the sheer volume of data generated by modern engineering systems and the increasing complexity of these systems have necessitated more advanced analytical tools, paving the way for AI.
AI offers the capability to process vast amounts of data, identify patterns, and make predictions with a level of speed and accuracy unattainable by traditional methods. This has profound implications for mechanical engineering, enabling more efficient design processes, predictive maintenance strategies, and optimized manufacturing operations. AI-driven tools can learn from historical data, adapt to new information, and continuously improve their performance, making them invaluable in tackling the multifaceted challenges of modern mechanical engineering.
An improved modulation technique suitable for a three level flying capacitor ...IJECEIAES
This research paper introduces an innovative modulation technique for controlling a 3-level flying capacitor multilevel inverter (FCMLI), aiming to streamline the modulation process in contrast to conventional methods. The proposed
simplified modulation technique paves the way for more straightforward and
efficient control of multilevel inverters, enabling their widespread adoption and
integration into modern power electronic systems. Through the amalgamation of
sinusoidal pulse width modulation (SPWM) with a high-frequency square wave
pulse, this controlling technique attains energy equilibrium across the coupling
capacitor. The modulation scheme incorporates a simplified switching pattern
and a decreased count of voltage references, thereby simplifying the control
algorithm.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Software Engineering and Project Management - Introduction, Modeling Concepts...Prakhyath Rai
Introduction, Modeling Concepts and Class Modeling: What is Object orientation? What is OO development? OO Themes; Evidence for usefulness of OO development; OO modeling history. Modeling
as Design technique: Modeling, abstraction, The Three models. Class Modeling: Object and Class Concept, Link and associations concepts, Generalization and Inheritance, A sample class model, Navigation of class models, and UML diagrams
Building the Analysis Models: Requirement Analysis, Analysis Model Approaches, Data modeling Concepts, Object Oriented Analysis, Scenario-Based Modeling, Flow-Oriented Modeling, class Based Modeling, Creating a Behavioral Model.
Software Engineering and Project Management - Introduction, Modeling Concepts...
Shock Isolation for Shelters
1. International Refereed Journal of Engineering and Science (IRJES)
ISSN (Online) 2319-183X, (Print) 2319-1821
Volume 6, Issue 6 (June 2017), PP.48-57
www.irjes.com 48 | Page
Shock Isolation for Shelters
Subash T Ra
, Sujinkumar L b
, Vijayalaxmi S b
, Kamalakannan Pb
a Chief Engineering Manager, Underground Design, L&T Construction, Chennai, India
b Engineering Manager, Underground Design, L&T Construction, Chennai, India
Abstract: In recent years, wide studies are carried out in usage of isolators in structures and equipment, for the
reduction of vibrations transmitted due to earthquakes, machine vibrations and any other minor disturbances.
But providing protection against vibrations caused due to blasts still remains challenging due to its high
amplitude and very short duration. In this paper, an effort has been put for providing shock isolation for
protective structure against dynamic load caused due to Blast, using mechanical springs devoid of damping.
Here an analytical study is made to understand the reduction of 10g acceleration to tolerable limit of 0.5g
acceleration. Simulations are carried out using ANSYS software to understand the behavior of the spring under
varying static and dynamic loads. Transmissibility of the shock from base to top of the spring is also studied
using software and results are found to be comparable with the theoretical approach. The results evident that
desired transmissibility can be achieved using mechanical springs
Keywords: Ground shock, mechanical springs, shock isolation, transmissibility
I. Introduction
When a blast explosion occurs, pressure waves with tremendous intensity are transmitted into air and
into ground as shock vibration. These waves which propagate radially outward from the vicinity of the
explosion will decrease its peak intensity with increase in duration. These waves when imposed on the ground
and on structures buried within the earth or on the surface will cause the motions termed as "ground shock".
Personnel and equipment housed in structures subjected to these ground shock, require protection against
possible injuries or damage which may result from impact forces. Such protection can be achieved by providing
energy absorbing system (shock isolation) between the structure and ground which is subjected to vibration.
The purpose of this article is to discuss on the design of mechanical springs as isolators for protection
of personnel and equipment against the effects of ground shock caused due to blast explosion.
II. Types Of Ground Vibrations
Ground vibrations generally are of different types depending upon the source which causes the
vibration. The common sources of vibration are machines, earthquake, winds, water waves, traffic, construction
works and explosions. The nature of vibrations caused by these sources is classified [7] as shown in the Fig. 1,
Figure 1: Types and Sources of vibrations
2. Shock Isolation for Shelters
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In case of earthquake, maximum amplitude generally occurs after sometime from the onset of the
earthquake and persists for certain duration of time. In contrast, Shock wave due to blast causes vibrations
which has very high amplitudes with very short time durations. The peak occurs immediately after the onset of
the shock on the structure. The vibration patterns produced by machines, earthquake and blast are as shown in
the following Fig. 2,
Figure 2: Vibration pattern
III. Effect Of Dampers On Vibrations
In case of Harmonic vibrations, dampers are very effective and useful in controlling the amplitude of
vibration as it doesn’t die out. Thus here a combination of spring and dampers shall be effective as isolator.
Dampers have reasonable contribution in case of vibrations caused due to earthquake, as the vibrations are not
constant and continuous over a longer period of time. The concept of damping does not have much significance
in case of Impulse loading [8]. This is because, the load with maximum amplitude acts for very short time
duration within which the dampers cannot absorb the energy, but it may help to reduce the vibrations caused due
to the impact of maximum wave. This study is undertaken ignoring the effect of external dampers and inherent
damping in the isolation.
IV. Ground Shock Phenomena
Air burst, surface burst and underground burst are the three major phenomena that causes vibrations on
the ground [2]. These phenomena are described for basic insight with pictorial representations,
4.1 Air burst
In Air burst, explosions occurs above ground and the pressure waves directly hits the ground before it
hits the structure. This causes shock vibrations in the ground. Fig. 3 gives the representation of air burst.
Figure 3: Air burst
4.2 Surface burst
This type of burst transfers the shock directly to the ground as it occurs on the surface of the ground.
This type of blast forms crater at the point of detonation. The intensity of shock vibration transferred in this type
will be higher when compared with the air burst. Fig. 4 represents surface burst.
Figure 4: Surface burst
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4.3 Underground burst
This type of burst occurs in the underground and has very high impact in creating vibration in the
ground. This will cause crater at that location. The vibration transferred to the ground in this type of blast will be
very high. Fig. 5 denotes Underground burst.
Figure 5: Underground burst
V. Effects Of Ground Shocks
The vibrations has various ill effects on the structure, equipment [2] and personnel [1] as discussed below,
5.1 On Structures
Vibrations when acting on the structures causes oscillations in vertical and horizontal directions. This
causes larger magnitude of shear force at the base of the structure and other secondary effects which may be
very much destructive. The concept of Resonance is unlikely as the natural frequency of the structure and the
blast will never match.
5.2 On Personnel
The effect of vibrations on persons depends upon magnitude, duration, frequency, rise time, body
positions and restrains. While experiencing the vibration, human body undergoes longitudinal effect where the
acceleration acts on the entire body parallel to the spine, transverse effect where the acceleration acts normal to
the spine and whiplash effect where the head moves with respect to shoulders either forward and backward or
sidewise. An indicative representation of bodily motions under horizontal acceleration is represented in Fig. 6.
Figure 6: Effect of vibrations on personnel
5.3 On Equipment
Equipment may undergo temporary or permanent failures due to the effect of external vibrations acting
on them. Temporary failures shall include malfunctions of the equipment for either short or long time depending
upon the extent of damage. Permanent failure includes breakage of the equipment and its dis-ability to serve.
Equipment which has to be in operating mode during emergency needs mandatory shock isolation for its un-
interrupted operation.
VI. Intensity Of Vibration
The intensity of vibrations caused due to blast explosion is very much greater than the accelerations felt
due to earthquakes. To highlight the multi-fold severity of blast vibration, a comparison of vibration intensity of
earthquake and blast vibration intensity is presented in figure 7. The earthquake parameters adopted are, Zones-
II to V, Importance factor of 1.5, Sa/g factor of 2.5 and response reduction factor of 2.5. Blast vibration
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parameters are 1000 pounder TNT at a distance of10m and 15m from the structure. It can be observed that
earthquake induced vibration is 0.27g and blast induced vibration is 9.61g, which is around 35 times higher than
the earthquake induced.
Figure 7: Intensity of vibration
It is evident that the vibrations caused due to blast explosions are manifold times the vibrations caused
by earthquake and this makes the isolation more challenging and complicated.
VII. Concept Of Shock Isolation
Shock is a condition where a single impulse of energy produced by a force is transferred to a system in
a short period of time and with large amplitude. The purpose of shock isolation is to limit the forces transmitted
to tolerable levels of the system to be protected. The systems that can be protected are structures, personnel and
equipment. The tolerance level in case of protecting the structure will be the maximum tolerable limit for
personnel and for equipment, the tolerable limit of most sensitive equipment will be considered. The Isolators
reduces the shock by undergoing deflection and releasing the energy over a longer period of time. The tolerance
level for human beings, at various postures, as-listed in TM-858-4 is tabulated in Table 1,
Table 1: Tolerance limits for human
Unrestrained
standing
A
B
10g
0.75g
-
0.5g
*
0.5g
Unrestrained
sitting
A
B
15g
0.75g
-
1g
*
1g
Restrained
sitting
A 15g 15g 15g
Restrained
Prone
A 40g 40g 15g
*
0.75g
CriteiaPosture
40g
0.75g
*
1g
Shock Direction
Unrestrained
prone
A
B
* Displacement must be limited, i.e attenuated to less than the distance between operator and nearest solid object
A = Limited g value to prevent internal Injury
B = Limited g to prevent possible impact injury
The mentioned tolerance levels shall be ensured through the concept of Transmissibility.
In this study, mechanical springs are used as isolators to control and reduce the vibrations to tolerable
limits.
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7.1 Mechanical Springs
These types of isolators can be used for isolation purpose as it has the capability of restoring back to its
original position once the applied load is removed. Both axial and lateral loads can be resisted by these types of
springs, but comparatively lateral capacity of these kind of spring is much lesser than that of vertical capacity.
Mechanical springs are adopted for this study, as it also has higher temperature resistance as compared to
elastomeric isolators.
7.2 Effect of Spring Material
7.2.1 Carbon steel
Carbon steel springs are most commonly used when compared to other types as they are less expensive
and readily available. These types of springs shall be used in the case of structures with less weight and for low
intensity blast loads.
7.2.2 Chromium steel
The alloy steel springs are generally used under conditions involving high stress and for shock
applications where impact loading occurs. Alloy steels can withstand higher and lower temperatures than the
high-carbon steels and are available in either the annealed or pre tempered conditions.
VIII. System Of Isolation
An Isolation system shall be coupled system or uncoupled system [2]. In case of coupled system,
transition or rotation along one orthogonal axis causes response along other axes. In case of uncoupled system,
transition or rotation along one axis causes response in the same axis. If the principal elastic axis and inertial
axis coincides at the center of gravity of the mass, then such system is called a balanced system which is most
preferred. The Fig. 8 explains the concept of coupled and uncoupled system. At point A, elastic center (EC) of
spring system and the center of gravity (CG) of mass coincides forming an uncoupled or balanced system. If the
CG of the building lies at point B, then the motions parallel to X axis alone is uncoupled. If the EC of spring
system and CG of the building lies at point C, then the motions in any directions are coupled.
Figure 8: System of Isolation
The basic spring parameters required for the design of spring isolators are described as follows,
IX. Spring Design Parameters
9.1 Shock Transmissibility, Ts
Transmissibility is the ratio between the vibrations experienced by the structure to the disturbing
vibration. With this concept, the acceptable tolerance limits shall be obtained. It is represented using (1),
Ts = go/gd - - - - - - - - - - - - - - - - - - (1)
Where, Ts = Shock transmissibility
go = Allowable limit of vibration
gd = Disturbing vibration
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Here in this study, the allowable limit of vibration is 0.5g and the disturbing vibration is 10g. Thus the
transmissibility will be 0.05 in this case.
9.2 Shock Natural Frequency, fn
The Natural frequency of shock is calculated from transmissibility relations established based on the shape
of the shock pulse. The transmissibility equations for various pulse shape is given below [3],
Pulse shape Transmissibility Equation
Blast or Ramp Ts≡3.2 fn to
Square wave Ts≡6 fn to
Half sine wave Ts≡4 fn to
Triangular wave Ts≡3.1 fn to
Here, the relation corresponding to blast pulse is taken for the calculation of shock natural frequency, i.e
Ts ≡ 3.2 fn to - - - - - - - - - - - - - - - (2)
Where, Ts = Shock transmissibility
fn = shock natural frequency
t0 = shock pulse length (seconds)
Indian Standards does not provide sufficient guideline for the calculation of duration of ground shock.
Also, limited literatures are available for the calculation of the same. UFC codes provide guidelines for the
calculation of shock pulse length in case of Air shock but not for Ground shock. In reality, the duration of shock
pulse in air will be more when compared to the duration in ground. Ground shock has lesser duration due to the
particle density of ground. Here, the shock pulse length is calculated considering Air shock, i.e. a value which
will be more than the actual pulse duration in ground, thus Shock natural frequency is calculated using (3),
which is obtained by rewriting (2),
fn = Ts/(3.2*t0) - - - - - - - - - - - - - (3)
9.3 Dynamic Deflection
In addition to the static deflection, spring also has to undergo dynamic deflection when the structure is
subjected to 10g acceleration. The dynamic deflection that the spring has to undergo for the protection of the
structure from the shock is derived using (4),
Δdyn = - - - - - - - - - - -(4)
9.4 Dynamic Spring Rate
The dynamic spring rate required for the spring to undergo the dynamic deflection is calculated using
force to deflection relation given by (5),
Kd = W / Δdyn - - - - - - - - - - - - - (5)
The above equation is re-written as follows by substituting (4)
Kd = - - - - - - - - - - - - (6)
Where, Kd = Dynamic stiffness of the spring
W = Weight of the structure
fn = Shock natural frequency
9.5 Static Spring Rate
The static stiffness required by the spring to withstand the static deflection is calculated using the
following empirical relation,
ks= kd/ 1.4 - - - - - - - - - - - - - - - -(7)
9.6 Static Deflection
The deflection of the spring under static condition is derived from the total weight of the structure and
the static stiffness calculated using the above empirical relation as follows,
∆sta= W/ ks - - - - - - - - - - - - - - -
(8)
Where, W = Weight of the structure
Ks = Static stiffness of the spring
Having calculated the spring parameters like Static stiffness, Dynamic stiffness, Static deflection and
Dynamic deflection, the design of the spring incorporating the same has to be done. Study of behavior of the
spring under static and dynamic loads contributes to precise arrangement of the system.
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X. Behavior Of Spring Under Static And Dynamic Load
The core design of the shock isolation system relay upon the layout of springs. This requires a detailed
study on the behavior of springs under static and dynamic loads. In the design life of structure, it may be
exposed to higher super imposed dead loads and live loads which plays a vital role in the behavior of springs for
isolation.
An analysis on a single spring is done using ANSYS to study the behavior of stiffness, transmissibility
and deflection under static and dynamic loading. A spring model of 500mm diameter and 50mm wire diameter
is modeled and placed between steel plates of size 0.7m x 0.7m. This study is done by varying vertical and
horizontal load both dynamically and statically.
BEAM188 element, which connects two nodes and has six degrees of freedom at each node is used for
modeling the coil and SHELL181 element, which is a four nodded element, with six degrees of freedom at each
node, is used for modeling the top and bottom plates. Bonded contact is used to make both elements to act as
single unit. The load acting on the spring is applied as lumped mass over the plate. In static analysis, base of
spring is considered as fixed to estimate static deformation. In case of transient analysis, velocity-time relation
corresponding to 10g acceleration is applied as boundary condition at base.
10.1 Static Studies
10.1.1 Varying Vertical load
In this case, the spring is acted upon by varying vertical load and exposed to a constant horizontal load
of 1000N. The Fig. 9 represents the vertical and horizontal stiffness behavior of spring under varying vertical
load. It shows that the vertical stiffness increases with the increase in vertical load. This load acts as a constraint
for the deflection in horizontal direction of the spring under horizontal load, thus decreasing the horizontal
stiffness.
Figure 9: Stiffness Variation-Horizontal Load Constant
10.1.2 Varying Horizontal Load
The Fig. 10 represents the variation of vertical and horizontal stiffness under constant vertical load of
1000N and varying horizontal load. It is observed that both horizontal and vertical stiffness decreases with
increase in lateral load. Vertical stiffness is found to decrease as the spring becomes weaker in vertical direction
due to P - ∆ effects. Reduction in horizontal stiffness can also be attributed to the same reason, but the reduction
is not so significant.
Figure10: Stiffness Variation-Vertical Load Constant
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10.2 Dynamic Studies
This study gives us an insight about the transmission of the ground vibration into the above supported
structure through the springs. This can be done only through dynamic analysis as this is time dependent. In this
case, the analysis is done for a varying vertical load of 900kg and 1000kg on the spring, subjected to
acceleration in vertical direction with varying duration. Ansys analysis showing the reduction in acceleration
experienced at the spring top against the acceleration applied at the spring bottom is represented in the Fig.11.
The Fig. 12 shows the behavior of transmissibility under two loads, 900kg and 1000kg for different duration of
impulse.
Figure 11: Analysis result for spring
subjected to 10g acceleration Figure 12: Transmissibility achieved for 900kg and1000kg
loading
10.3 Inference
10.3.1 From static Studies
1. Under varying vertical load and constant horizontal load, it is inferred that the vertical stiffness increases
with the increase in the vertical load and constant horizontal load. The increased vertical stiffness acts as a
constraint for the horizontal deflection under horizontal load.
2. Under varying horizontal load and constant vertical load, the horizontal stiffness of the spring decreases
with increase in horizontal load. This is due to the P-∆ effect and decreased stability of the spring.
10.3.2 From dynamic studies
1. The behavior of the spring under dynamic load is entirely different. As the load on the spring is increased
for an amplitude of vertical acceleration and certain duration, the vibration transmitted is found to decrease.
This reduction in transmissibility is due to the mass on the isolator which resists the acceleration acting for
short duration. The vibration transmitted (transmissibility) is found to increase only with the increase in the
duration of acceleration acting. As the duration of force (acceleration) pushing the mass above increases,
the transmissibility increases. Thus, the successful usage of the mechanical spring, depends upon the study
of its complex behavior under static loads, dynamic loads, and direction of the dynamic load.
XI. Spring Design
The Isolator can be designed as helical coil with the spring parameters mentioned
11.1. Spring stiffness
The axial spring rate of helical coil spring is given by following relation,
K = - - - - - - - - - - - - - - -(9)
Where, d = Spring bar diameter
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D = Nominal spring diameter
G = Shear modulus for spring material
N = Number of active coils
From the above equation it is clear that combinations of coil diameter, spring diameter and number of active
coils will satisfy the required spring rate. Active coils are those coils which are responsible for spring’s reaction
to loads or displacements and Inactive coils are those that helps to provide attachment.
11.2. Total deflection
Spring undergoes bottoming out condition when it is fully compressed without any space in between
them. In such a condition a factor of safety against bottoming has to be considered with the total deflection
calculated. Total deflection is calculated using (10),
∆t = Cf (∆st + ∆dyn) - - - - - - - - - - - - - - - - (10)
Where, ∆t = Total deflection
Cf = Factor of safety against bottoming
∆st = Static deflection of spring
∆dyn = Dynamic deflection of spring
11.3. Shear stress check
The main property of the spring is that it has to regain back to its original position once the externally
applied load is removed, that is it shouldn’t undergo inelastic deformation. In order to prevent inelastic
deformation of the spring, the coils of the spring are designed such that the elastic shear strength is not exceeded
under full compression. The maximum compressive load is given as below,
P* = k ∆t - - - - - - - - - - - - - - - - -- (11)
Where, k = Stiffness of spring
∆t = Total deflection of spring
The maximum shear stress under the compressive load is defined by following (12),
τmax = K - - - - - - - - - - - - - - -(12)
Where, K = Wahl’s correction factor which accounts for direct shear and curvature effect of spring given as
+
C = Spring Index
P* = Maximum compressive force
D = Spring diameter
d = Coil diameter
The maximum shear stress calculated should be lower than the shear strength of the spring material.
11.4. Lateral Stiffness
Every helical spring possess certain amount of lateral stiffness. Assessing the lateral stiffness of the
spring provides an insight about the requirement of spring in lateral direction. For compression springs under
vertical and lateral loads with Young’s modulus E=30000000PSI (2.07 X 1011 N/m2) and G = 11500000PSI
(7.93 X 1010 N/m2), Harris –Crede has given the following relation for lateral spring rate
Kh = = - - - - - - - - (13)
Where, kh = Lateral stiffness
Fh = Lateral Force
∆h = Lateral deflection due to horizontal force
Ch = Factor depending on ∆st / H and H/D
Hs = Compressed height of spring (h - ∆st)
The factor Ch can be obtained from figure 8-10 of TM 5-858-4
** (The above equation is applicable only for the specified Young’s modulus and Bulk modulus)
11.5. Spring Surge check
When there are impact loads on the springs, the stress propagates along the spring wire. The end coil of
the spring in contact with the applied load takes up whole of the deflection and then it transmits a large part of
its deflection to the adjacent coils. This wave of compression travels along the spring indefinitely. Resonance
might occur depending upon time traveled. This results in very large deflections and correspondingly very high
stresses. Under these conditions, it is possible that the spring may fail. This phenomenon is called surge. It is
important that the springs used for isolation be checked for the occurrence of Surge. It can be avoided by
keeping the natural frequency of the spring 15 – 20 times away from frequency of the shock acting on it. The
natural frequency of spring can be calculated using the below relation,
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fn = - - - - - - - - - - -(16)
Where, d = Coil diameter
D = Spring diameter
n = Number of active coils
G = Rigidity Modulus
g = Disturbing vibration
ρ = Density of material used
11.6. Rattle Space Requirements
It becomes necessary to calculate the rattle space requirements in order to plan space for the spring
arrangement. This value shall be obtained from maximum vertical and horizontal displacement.
XII.Conclusions
The following points are discussed and inferred from the study made
Mechanical springs are preferred to be a suitable option for the isolation of protective structure from shocks
due to blasts.
Analytical study on the behavior of the springs is made under static and dynamic loads.
From static analysis, the increase of vertical load under constant horizontal load, increases the vertical
stiffness of the spring making the system rigid. The increase in load in horizontal direction under constant
vertical load, decreases the horizontal stiffness of the spring and makes the system instable.
In case of dynamic loading with vertical acceleration, the increase in vertical load reduces the vibration
transmitted to the structure from the ground, as the increased load acts like a constraint for movement of the
spring. The increase in the duration of the impulse, increases the vibration transmitted into the structure.
Though the behavior of the spring under horizontal acceleration is not covered in this paper, it is suggested
to provide horizontal springs as they help in reducing the transmissibility in horizontal direction.
Efficient isolation system using Mechanical springs can be achieved by fully understanding the behavior in
all the three orthogonal axes under static and dynamic loads.
XIII. Scope For Future Work
Combined action of vertical and horizontal springs further reduces the transmissibility into the
structure. This combined effect shall be studied both analytical and numerically. Contribution of the effect of
external and internal damping in reducing the after effects of the impulse load on the structure can be studied.
Strain hardening might reduce the efficiency of the spring due to plastic deformation. A detailed study
incorporating the effect of strain hardening shall be done to verify the effectiveness of the spring.
References
[1]. TM 5-858-4 Technical Manual – Design Facilities to Resist Nuclear Weapon Effects – Shock Isolation
Systems
[2]. UFC 3-3403-02 Unified Facilities Criteria – Structures to Resist the Effects of Accidental Explosion
[3]. Theory of Vibration Isolators –RPM Mechanical Inc. – www.rpmmech.com
[4]. Analysis and Design of Reinforced Concrete Structures with Spring Base Isolation – Tun Myint Aung,
Tin Tin Win, Nyan Myint Kyaw
[5]. Full Base Isolation for Earthquake protection by Helical Springs and Visco dampers – Neeraj Kumar
Dubey
[6]. Seismic Isolation in buildings to be a practical reality: Behavior of structure and installation technique –
A.B.M. Saiful Islam, Mohammad Jameel, Mohd Zamin Jumaat
[7]. Earthquake Resistant Design of Structures – Pankaj Agarwal, Manish Shrikhande
[8]. Basics of Structural Dynamics and Aseismic Design – S. R. Damodarasamy, S. Kavitha.