Creep rahul dhibar
•Download as PPTX, PDF•
0 likes•67 views
This document discusses creep in materials. Creep is the slow deformation of a material under stress over time, especially at high temperatures. It occurs due to mechanisms like bulk diffusion, grain boundary diffusion, and dislocation movement. Creep testing involves applying a constant load to a sample and measuring the strain over time until failure. The three stages of creep are primary, secondary, and tertiary. Creep can be reduced by choosing materials resistant to it, like alloys, and optimizing properties like grain size and vacancies. Creep is an important consideration in designing structures and components that operate at high temperatures, such as those found in power plants.
Report
Share
Report
Share
Recommended
creep
Creep is a time-dependent deformation that occurs under an applied load, usually at high temperatures. It results in a material increasing in length over time. A classical creep curve shows three stages - primary, secondary, and tertiary creep. Primary creep has a rapid initial rate that slows over time, secondary creep has a relatively uniform rate, and tertiary creep accelerates until failure. Creep rate is affected by temperature and stress level, with higher temperatures and stresses increasing creep. Different materials exhibit different creep mechanisms depending on factors like their crystal structure and grain size.
Creep
Creep is the time-dependent deformation of a material under constant stress at high temperatures. It occurs due to the movement of vacancies and dislocations within a material's microstructure. The critical temperature for creep to occur is 40% of the material's melting temperature. Different creep mechanisms dominate depending on the material, stress levels, and temperatures. Creep testing involves applying a constant load to a sample and measuring the strain over time until failure. The three stages of creep are primary, secondary, and tertiary creep. Creep can lead to failure of components in applications like turbines and nuclear reactors where high stresses and temperatures are present.
Creep
This document discusses creep, which is the time-dependent plastic deformation of materials under constant stress that is below their yield strength. It occurs more at higher temperatures, especially above 35% of the melting point for metals. Creep testing involves applying a constant stress and measuring strain over time. The resulting creep curve shows three stages: primary, secondary, and tertiary creep. Creep is influenced by mechanisms like dislocation climb, vacancy diffusion, and grain boundary sliding. Creep can be reduced by using high-melting point alloys, coarse grains, precipitation hardening, and dispersion strengthening. Creep is an important consideration in designing components that operate at high temperatures, such as turbine blades and steam pipes.
Creep of metals
Creep is the time-dependent deformation of a material under stresses below its yield strength and at elevated temperatures. It occurs as the applied load causes the gradual distortion of the material's internal structure over time. Creep is an important consideration for components that operate at high temperatures, such as those found in oil refineries and steam turbines, as excessive creep deformation can lead to failure if adjacent parts come into contact. The temperature at which different metals will experience creep depends on their melting points, with creep typically occurring above 0.5 times the absolute melting temperature of the metal. The creep rate of a material is characterized by an initial rapid decrease in strain rate, followed by a steady minimum rate, and then an acceleration until failure.
Creep Failure
This document discusses creep failure, which is the slow, time-dependent deformation of materials under constant stress, especially at high temperatures. It defines key creep terms and concepts, including the classic creep curve with primary, secondary, and tertiary creep stages. The main creep mechanisms are described as bulk diffusion, grain boundary diffusion, and dislocation climb/creep. Creep failure occurs through the nucleation and growth of cracks and cavities. Methods to prevent creep failure include using single crystal materials, solid solution strengthening, high melting temperature alloys, and consulting creep test data for lifetime expectations under loading conditions.
creep deformation of the Materials
This document discusses creep deformation, which is the time-dependent plastic deformation of materials under constant stress, especially at elevated temperatures. It defines creep and identifies the primary mechanisms as bulk diffusion, grain boundary diffusion, and dislocation climb/creep. The document details experimental creep tests to determine creep rates and parameters, which provide prediction of life expectancy. It also discusses design considerations like reducing grain boundaries and employing high melting temperature materials to minimize creep deformation.
Creep testing machines
The document discusses creep testing machines and the creep testing process. It defines creep as time-dependent deformation under constant load at high temperatures. Creep is important for three types of high temperature applications: displacement-limited, rupture-limited, and stress-relaxation-limited. The creep testing machine allows specimens to be subjected to constant load inside a furnace at elevated and controlled temperatures to measure performance over time. A typical creep curve shows three stages: primary creep with decreasing creep rate, steady-state creep with linear strain increase, and tertiary creep with rapid strain increase until failure or rupture.
Creep Testing
This document outlines the process for creep testing. It discusses the mechanism of creep, specimen preparation, testing machines, procedures, results including creep curves, and the effect of temperature. It also covers rupture strength measurement using the Larson-Miller parameter and precautions for the testing process. Applications of creep testing in industry include displacement-limited components like turbine rotors, rupture-limited parts like steam pipes, and stress-relaxation-limited uses such as suspended cables.
Recommended
creep
Creep is a time-dependent deformation that occurs under an applied load, usually at high temperatures. It results in a material increasing in length over time. A classical creep curve shows three stages - primary, secondary, and tertiary creep. Primary creep has a rapid initial rate that slows over time, secondary creep has a relatively uniform rate, and tertiary creep accelerates until failure. Creep rate is affected by temperature and stress level, with higher temperatures and stresses increasing creep. Different materials exhibit different creep mechanisms depending on factors like their crystal structure and grain size.
Creep
Creep is the time-dependent deformation of a material under constant stress at high temperatures. It occurs due to the movement of vacancies and dislocations within a material's microstructure. The critical temperature for creep to occur is 40% of the material's melting temperature. Different creep mechanisms dominate depending on the material, stress levels, and temperatures. Creep testing involves applying a constant load to a sample and measuring the strain over time until failure. The three stages of creep are primary, secondary, and tertiary creep. Creep can lead to failure of components in applications like turbines and nuclear reactors where high stresses and temperatures are present.
Creep
This document discusses creep, which is the time-dependent plastic deformation of materials under constant stress that is below their yield strength. It occurs more at higher temperatures, especially above 35% of the melting point for metals. Creep testing involves applying a constant stress and measuring strain over time. The resulting creep curve shows three stages: primary, secondary, and tertiary creep. Creep is influenced by mechanisms like dislocation climb, vacancy diffusion, and grain boundary sliding. Creep can be reduced by using high-melting point alloys, coarse grains, precipitation hardening, and dispersion strengthening. Creep is an important consideration in designing components that operate at high temperatures, such as turbine blades and steam pipes.
Creep of metals
Creep is the time-dependent deformation of a material under stresses below its yield strength and at elevated temperatures. It occurs as the applied load causes the gradual distortion of the material's internal structure over time. Creep is an important consideration for components that operate at high temperatures, such as those found in oil refineries and steam turbines, as excessive creep deformation can lead to failure if adjacent parts come into contact. The temperature at which different metals will experience creep depends on their melting points, with creep typically occurring above 0.5 times the absolute melting temperature of the metal. The creep rate of a material is characterized by an initial rapid decrease in strain rate, followed by a steady minimum rate, and then an acceleration until failure.
Creep Failure
This document discusses creep failure, which is the slow, time-dependent deformation of materials under constant stress, especially at high temperatures. It defines key creep terms and concepts, including the classic creep curve with primary, secondary, and tertiary creep stages. The main creep mechanisms are described as bulk diffusion, grain boundary diffusion, and dislocation climb/creep. Creep failure occurs through the nucleation and growth of cracks and cavities. Methods to prevent creep failure include using single crystal materials, solid solution strengthening, high melting temperature alloys, and consulting creep test data for lifetime expectations under loading conditions.
creep deformation of the Materials
This document discusses creep deformation, which is the time-dependent plastic deformation of materials under constant stress, especially at elevated temperatures. It defines creep and identifies the primary mechanisms as bulk diffusion, grain boundary diffusion, and dislocation climb/creep. The document details experimental creep tests to determine creep rates and parameters, which provide prediction of life expectancy. It also discusses design considerations like reducing grain boundaries and employing high melting temperature materials to minimize creep deformation.
Creep testing machines
The document discusses creep testing machines and the creep testing process. It defines creep as time-dependent deformation under constant load at high temperatures. Creep is important for three types of high temperature applications: displacement-limited, rupture-limited, and stress-relaxation-limited. The creep testing machine allows specimens to be subjected to constant load inside a furnace at elevated and controlled temperatures to measure performance over time. A typical creep curve shows three stages: primary creep with decreasing creep rate, steady-state creep with linear strain increase, and tertiary creep with rapid strain increase until failure or rupture.
Creep Testing
This document outlines the process for creep testing. It discusses the mechanism of creep, specimen preparation, testing machines, procedures, results including creep curves, and the effect of temperature. It also covers rupture strength measurement using the Larson-Miller parameter and precautions for the testing process. Applications of creep testing in industry include displacement-limited components like turbine rotors, rupture-limited parts like steam pipes, and stress-relaxation-limited uses such as suspended cables.
3814931 creep resistance
The document discusses materials at high temperatures and creep. It describes how microstructure and mechanical properties change at high temperatures, including grain growth, vacancy formation, and increased mobility of dislocations and atoms. It then focuses on creep, which is the time-dependent deformation of materials under constant load at high temperatures. The typical creep curve is presented, showing the stages of instantaneous deformation, primary creep, secondary creep, and tertiary creep. Parameters that characterize creep behavior like steady-state creep rate and time to rupture are discussed. The effects of stress and temperature on creep are described. Models for predicting creep behavior like the Larson-Miller relation are presented. Creep damage mechanisms involving void formation and linkage are described. The document concludes
Introduction of creep
This document discusses creep, which is the time-dependent permanent deformation of materials under constant stress, especially at high temperatures. It identifies the primary mechanisms of creep as diffusion and dislocation climb, which are significant at grain boundaries and in the bulk. Creep tests are described where strain over time is measured under a constant load. Classical creep curves are analyzed to determine steady state creep rates and model parameters. Stress rupture curves map time to failure at different stresses and temperatures. The threshold for creep in an alloy is given as 40% of its melting temperature. An example calculates if lead would creep at room temperature. Creep of ice is also discussed.
Lesson 62 and 63 rupture test
This document discusses stress-rupture tests and compares them to creep tests. Stress-rupture tests are carried out at higher stress levels than creep tests and are always conducted until material failure. The time to failure at a given stress and temperature is the key data obtained. Structural changes during creep are also reviewed, including deformation by slip, sub-grain formation, and grain boundary sliding. Differences between creep tests and stress-rupture tests include higher loads, higher creep rates, and tests being terminated at 1000 hours for stress-rupture tests versus up to 10,000 hours for creep tests.
Creep & fatigue
Creep and fatigue are long-term mechanical properties that determine how materials perform under constant mechanical stress or repeated loading over time. Creep is the slow deformation of a material under a constant load, while fatigue is the failure of mechanical properties from repeated stress or strain. Testing these properties provides critical data for designing plastic components used in applications with long-term or cyclic loading, such as those subjected to constant stress, fluctuating temperatures, or repeated flexing. Standard tests measure things like creep strain over time under tension or flexure and fatigue life through the number of cycles before failure under various stress levels and conditions. The test data can be used to characterize materials and ensure dimensional stability and lifespan of parts in their intended applications.
Creep
The document discusses the concept of creep, which is the slow plastic deformation of a material under a constant load below its proportional limit. Creep can continue until fracture and usually occurs at high temperatures. It is an important property to consider in designing engines, boilers, and turbines. Creep occurs in three stages - primary, secondary, and tertiary. The secondary stage where creep occurs at a constant rate is used to estimate service life. Creep resistance depends on factors like heat treatment, grain size, strain hardening, and alloying elements. Theories describe creep rate increasing with stress and temperature according to specific equations.
Creep
Creep is defined as time-dependent inelastic strain under sustained load and elevated temperature. Creep testing involves subjecting metal specimens to high stress and temperature to produce time-dependent inelastic strain. The creep curve exhibits three stages: primary, secondary, and tertiary. Creep is affected by stress, temperature, and time based on empirical formulas. Creep behavior is more complex for nonmetals like concrete and wood due to additional factors like aging, moisture content, and anisotropy. Creep testing and modeling helps understand material deformation over long periods under load.
CREEP
Creep is the slow, progressive deformation of a material under constant stress over time. It is dependent on both time and temperature. During a creep test, a constant stress is applied to a specimen and its deformation is measured over time. Typically, a creep curve will show an initial instantaneous elastic deformation followed by primary, secondary, and tertiary creep stages. The addition of nanoparticles like carbon nanotubes or clay to polymers can improve their creep resistance by acting as barriers to hinder molecular chain movement and reorientation under stress. Creep tests are used to characterize a material's creep performance by measuring its creep compliance over time under an applied load.
Failure mechanism: CREEP
Mumbai University.
Mechanical Engineering
SEM III
Material Technology
Module 2.3
Creep:
Definition and significance of creep, Effect of temperature and creep on mechanical behaviours of materials, Creep testing and data presentation and analysis, Mechanism and types of creep, Analysis of classical creep curve and use of creep rate in designing of products for load-bearing applications, Creep Resistant materials
Analysis of Ductile-to-Brittle Transition Temperature of Mild Steel
The Ductile-to-Brittle Transition Temperature (DBTT) is a phe nomenon that is widely observed in metals. Below critical temperature (DBTT),the material suddenly loss ductil ity and becomes brittle. The controlling mechanism of this transition still remains unclear despite of la rge efforts made in experimental and theoretical investigation. All ferrous materials (except the a ustenitic grades) exhibit a transition from ductile to brittle when tested above and below a certain temperature,calle d as Transition Temperature. The paper deals with the determination of the �Ductile to Brittle Trans ition Temperature of stainless steel. Work carried out in this is purchasing the material followed by test s pecimen preparation. The specimens then keep in the liquid nitrogen for cooling for soaking time of 15 min. Then th e actual charpy impact testing of the specimens at variable temperature ranging are carried out in controlled atmosphere. The readings taken are the impact energy (joules) of specimen at specific temper ature. The graph of energy absorbed vs temperature is plotted to get the range of transition temperature.
Fatigue and creep rapture
The document discusses three main types of material failure: fatigue failure, failure under fluctuating stress, and creep failure. Fatigue failure occurs when a material breaks under cyclic stresses that are lower than the material's static load capacity. Creep failure happens at high temperatures over long periods of time due to constant stresses. The key factors that influence fatigue life and creep behavior include stress levels, temperature, surface quality, microstructure, and environment. Crack initiation and propagation play an important role in fatigue failure. Different creep mechanisms dominate depending on the material, stress levels, and temperature.
Ductile to brittle transition
Causes of Ductile to Brittle transition, Ductile to brittle transition temperature, Types of Impact tests
Fatigue and creep
Fatigue and creep are fundamental mechanical properties of materials. Fatigue is the failure of a material caused by repeated application of cyclic stresses, even if the stresses are below the yield strength of the material. It can lead to loss of strength, ductility, and uncertainty in service life. Creep is the slow deformation of materials under a constant load at high temperatures. Creep deformation occurs in three stages - primary, secondary, and tertiary. Factors like temperature, grain size, heat treatment, and alloying elements affect the fatigue and creep properties of materials. Mechanisms like dislocation climb, vacancy diffusion, and grain boundary sliding contribute to creep deformation at high temperatures.
Fatigue consideration in design
Fatigue is the weakening of a material caused by repeatedly applied loads. It leads to premature failure under cyclic stresses or strains, similar to how humans experience fatigue from repetitive tasks. There are three stages of fatigue failure: crack initiation, crack propagation, and fracture. Many factors influence fatigue life, including surface condition, size, load type, temperature, and manufacturing variables. Empirical models incorporate factors like surface finish, size, load type, and temperature to adjust the expected fatigue life of a component based on these influential characteristics.
Failure of materials
This document defines and describes various failure modes including fracture, fatigue, creep, and corrosion. It discusses how fracture occurs through crack initiation and propagation, and is influenced by temperature, strain rate, and material properties. Fatigue refers to failure from repeated or fluctuating stresses. Creep is time-dependent plastic deformation that occurs under high or low temperatures depending on the material. Corrosion is the destructive interaction of a material with its environment through chemical or electrochemical reactions.
Failure Due to overloading
The failure or fracture of a product or component as a result of a single event is known as mechanical overload. It is a common failure mode, and may be contrasted with fatigue, creep, rupture, or stress relaxation.
BRITTLE FAILURE
In a brittle overload failure, separation of the two halves isn’t quite instantaneous, but proceeds at a tremendous rate, nearly at the speed of sound in the material. The crack begins at the point of maximum stress, then grows across by cleavage of the individual material grains. One of the results of this is that the direction of the fracture path is frequently indicated by chevron marks that point toward the origin of the failure.
Fm fatigue
This document summarizes key concepts regarding fatigue crack propagation. It discusses three stages of crack growth: (1) crack initiation, where microcracks form due to cyclic stresses; (2) crack propagation, where cracks grow according to Paris' law and form fatigue striations; and (3) final failure, where cracks rapidly grow unstable until catastrophic fracture. Critical factors like stress levels, number of cycles, and material properties are outlined. Paris' law and sigmoidal crack growth curves are also summarized.
Fractue fatigue and creep
This document discusses different failure mechanisms in materials including fracture, fatigue, and creep. It defines fracture as breaking into two or more pieces due to an external load. There are two main steps in the fracture process: crack initiation and crack propagation. Fracture can be brittle, exhibiting little plastic deformation before failure, or ductile. Creep is the permanent deformation of materials over time when under a constant load at high temperatures. Creep curves show the relationship between creep strain and time. Factors like temperature, grain size, and alloy composition affect a material's susceptibility to creep.
Fracture Mechanics & Failure Analysis:Lecture DBTT
During World War II, some welded transport ships suddenly fractured at around 40 degrees Celsius, despite room-temperature tests showing adequate ductility. Toughness tests determine if a material exhibits a ductile-to-brittle transition with decreasing temperature, represented by a curve showing decreasing impact energy absorption and increasing percentage of shear fracture over a temperature range. The ductile-to-brittle transition occurs as temperature decreases, with ductile fracture at high temperatures and brittle fracture below a certain temperature.
Fracture
This document discusses different types of material fractures: brittle, ductile, fatigue, and creep. Brittle fractures occur with little plastic deformation, while ductile fractures involve significant plastic deformation. Fatigue fractures result from repeated cyclic stresses below the material's tensile strength. Creep fractures happen due to excessive deformation over time under steady loads. The mechanisms of each type are also described, such as Griffith's theory of stress concentrations leading to brittle fractures or dislocation movement causing creep fractures.
Fractures
This document discusses different types of fractures including brittle, ductile, fatigue, and creep fractures. It focuses on explaining brittle fracture in more detail. Brittle fracture occurs with minimal plastic deformation and when the broken pieces are fitted back together, the original shape and dimensions are restored. It is defined as fracture occurring at or below the material's elastic limit. The document then describes Griffith's theory of brittle fracture, which postulates that microcracks are always present in brittle materials and concentrate stress at their tips, leading to crack growth and fracture when the applied energy exceeds the strain energy of the cracks.
HIGH TEMEPRATURE CREEP OF CERAMICS AND ITS MECHANISM
This presentation gives us the idea about high temperature creep and its mechanism in ceramics
Fracture Mechanics & Failure Analysis: creep and stress rupture
Fracture Mechanics & Failure Analysis: creep and stress ruptureNED University of Engineering and Technology
The document discusses creep and stress rupture behavior of materials at high temperatures. It provides an introduction to creep and stress rupture tests, describing the three stages of creep curves and how applied stress and temperature affect creep behavior. Different deformation mechanisms at high temperatures are discussed, including dislocation glide/creep, diffusion creep, and grain boundary sliding. The document also covers topics such as structural changes during creep, superplasticity, and fracture modes at elevated temperatures.More Related Content
What's hot
3814931 creep resistance
The document discusses materials at high temperatures and creep. It describes how microstructure and mechanical properties change at high temperatures, including grain growth, vacancy formation, and increased mobility of dislocations and atoms. It then focuses on creep, which is the time-dependent deformation of materials under constant load at high temperatures. The typical creep curve is presented, showing the stages of instantaneous deformation, primary creep, secondary creep, and tertiary creep. Parameters that characterize creep behavior like steady-state creep rate and time to rupture are discussed. The effects of stress and temperature on creep are described. Models for predicting creep behavior like the Larson-Miller relation are presented. Creep damage mechanisms involving void formation and linkage are described. The document concludes
Introduction of creep
This document discusses creep, which is the time-dependent permanent deformation of materials under constant stress, especially at high temperatures. It identifies the primary mechanisms of creep as diffusion and dislocation climb, which are significant at grain boundaries and in the bulk. Creep tests are described where strain over time is measured under a constant load. Classical creep curves are analyzed to determine steady state creep rates and model parameters. Stress rupture curves map time to failure at different stresses and temperatures. The threshold for creep in an alloy is given as 40% of its melting temperature. An example calculates if lead would creep at room temperature. Creep of ice is also discussed.
Lesson 62 and 63 rupture test
This document discusses stress-rupture tests and compares them to creep tests. Stress-rupture tests are carried out at higher stress levels than creep tests and are always conducted until material failure. The time to failure at a given stress and temperature is the key data obtained. Structural changes during creep are also reviewed, including deformation by slip, sub-grain formation, and grain boundary sliding. Differences between creep tests and stress-rupture tests include higher loads, higher creep rates, and tests being terminated at 1000 hours for stress-rupture tests versus up to 10,000 hours for creep tests.
Creep & fatigue
Creep and fatigue are long-term mechanical properties that determine how materials perform under constant mechanical stress or repeated loading over time. Creep is the slow deformation of a material under a constant load, while fatigue is the failure of mechanical properties from repeated stress or strain. Testing these properties provides critical data for designing plastic components used in applications with long-term or cyclic loading, such as those subjected to constant stress, fluctuating temperatures, or repeated flexing. Standard tests measure things like creep strain over time under tension or flexure and fatigue life through the number of cycles before failure under various stress levels and conditions. The test data can be used to characterize materials and ensure dimensional stability and lifespan of parts in their intended applications.
Creep
The document discusses the concept of creep, which is the slow plastic deformation of a material under a constant load below its proportional limit. Creep can continue until fracture and usually occurs at high temperatures. It is an important property to consider in designing engines, boilers, and turbines. Creep occurs in three stages - primary, secondary, and tertiary. The secondary stage where creep occurs at a constant rate is used to estimate service life. Creep resistance depends on factors like heat treatment, grain size, strain hardening, and alloying elements. Theories describe creep rate increasing with stress and temperature according to specific equations.
Creep
Creep is defined as time-dependent inelastic strain under sustained load and elevated temperature. Creep testing involves subjecting metal specimens to high stress and temperature to produce time-dependent inelastic strain. The creep curve exhibits three stages: primary, secondary, and tertiary. Creep is affected by stress, temperature, and time based on empirical formulas. Creep behavior is more complex for nonmetals like concrete and wood due to additional factors like aging, moisture content, and anisotropy. Creep testing and modeling helps understand material deformation over long periods under load.
CREEP
Creep is the slow, progressive deformation of a material under constant stress over time. It is dependent on both time and temperature. During a creep test, a constant stress is applied to a specimen and its deformation is measured over time. Typically, a creep curve will show an initial instantaneous elastic deformation followed by primary, secondary, and tertiary creep stages. The addition of nanoparticles like carbon nanotubes or clay to polymers can improve their creep resistance by acting as barriers to hinder molecular chain movement and reorientation under stress. Creep tests are used to characterize a material's creep performance by measuring its creep compliance over time under an applied load.
Failure mechanism: CREEP
Mumbai University.
Mechanical Engineering
SEM III
Material Technology
Module 2.3
Creep:
Definition and significance of creep, Effect of temperature and creep on mechanical behaviours of materials, Creep testing and data presentation and analysis, Mechanism and types of creep, Analysis of classical creep curve and use of creep rate in designing of products for load-bearing applications, Creep Resistant materials
Analysis of Ductile-to-Brittle Transition Temperature of Mild Steel
The Ductile-to-Brittle Transition Temperature (DBTT) is a phe nomenon that is widely observed in metals. Below critical temperature (DBTT),the material suddenly loss ductil ity and becomes brittle. The controlling mechanism of this transition still remains unclear despite of la rge efforts made in experimental and theoretical investigation. All ferrous materials (except the a ustenitic grades) exhibit a transition from ductile to brittle when tested above and below a certain temperature,calle d as Transition Temperature. The paper deals with the determination of the �Ductile to Brittle Trans ition Temperature of stainless steel. Work carried out in this is purchasing the material followed by test s pecimen preparation. The specimens then keep in the liquid nitrogen for cooling for soaking time of 15 min. Then th e actual charpy impact testing of the specimens at variable temperature ranging are carried out in controlled atmosphere. The readings taken are the impact energy (joules) of specimen at specific temper ature. The graph of energy absorbed vs temperature is plotted to get the range of transition temperature.
Fatigue and creep rapture
The document discusses three main types of material failure: fatigue failure, failure under fluctuating stress, and creep failure. Fatigue failure occurs when a material breaks under cyclic stresses that are lower than the material's static load capacity. Creep failure happens at high temperatures over long periods of time due to constant stresses. The key factors that influence fatigue life and creep behavior include stress levels, temperature, surface quality, microstructure, and environment. Crack initiation and propagation play an important role in fatigue failure. Different creep mechanisms dominate depending on the material, stress levels, and temperature.
Ductile to brittle transition
Causes of Ductile to Brittle transition, Ductile to brittle transition temperature, Types of Impact tests
Fatigue and creep
Fatigue and creep are fundamental mechanical properties of materials. Fatigue is the failure of a material caused by repeated application of cyclic stresses, even if the stresses are below the yield strength of the material. It can lead to loss of strength, ductility, and uncertainty in service life. Creep is the slow deformation of materials under a constant load at high temperatures. Creep deformation occurs in three stages - primary, secondary, and tertiary. Factors like temperature, grain size, heat treatment, and alloying elements affect the fatigue and creep properties of materials. Mechanisms like dislocation climb, vacancy diffusion, and grain boundary sliding contribute to creep deformation at high temperatures.
Fatigue consideration in design
Fatigue is the weakening of a material caused by repeatedly applied loads. It leads to premature failure under cyclic stresses or strains, similar to how humans experience fatigue from repetitive tasks. There are three stages of fatigue failure: crack initiation, crack propagation, and fracture. Many factors influence fatigue life, including surface condition, size, load type, temperature, and manufacturing variables. Empirical models incorporate factors like surface finish, size, load type, and temperature to adjust the expected fatigue life of a component based on these influential characteristics.
Failure of materials
This document defines and describes various failure modes including fracture, fatigue, creep, and corrosion. It discusses how fracture occurs through crack initiation and propagation, and is influenced by temperature, strain rate, and material properties. Fatigue refers to failure from repeated or fluctuating stresses. Creep is time-dependent plastic deformation that occurs under high or low temperatures depending on the material. Corrosion is the destructive interaction of a material with its environment through chemical or electrochemical reactions.
Failure Due to overloading
The failure or fracture of a product or component as a result of a single event is known as mechanical overload. It is a common failure mode, and may be contrasted with fatigue, creep, rupture, or stress relaxation.
BRITTLE FAILURE
In a brittle overload failure, separation of the two halves isn’t quite instantaneous, but proceeds at a tremendous rate, nearly at the speed of sound in the material. The crack begins at the point of maximum stress, then grows across by cleavage of the individual material grains. One of the results of this is that the direction of the fracture path is frequently indicated by chevron marks that point toward the origin of the failure.
Fm fatigue
This document summarizes key concepts regarding fatigue crack propagation. It discusses three stages of crack growth: (1) crack initiation, where microcracks form due to cyclic stresses; (2) crack propagation, where cracks grow according to Paris' law and form fatigue striations; and (3) final failure, where cracks rapidly grow unstable until catastrophic fracture. Critical factors like stress levels, number of cycles, and material properties are outlined. Paris' law and sigmoidal crack growth curves are also summarized.
Fractue fatigue and creep
This document discusses different failure mechanisms in materials including fracture, fatigue, and creep. It defines fracture as breaking into two or more pieces due to an external load. There are two main steps in the fracture process: crack initiation and crack propagation. Fracture can be brittle, exhibiting little plastic deformation before failure, or ductile. Creep is the permanent deformation of materials over time when under a constant load at high temperatures. Creep curves show the relationship between creep strain and time. Factors like temperature, grain size, and alloy composition affect a material's susceptibility to creep.
Fracture Mechanics & Failure Analysis:Lecture DBTT
During World War II, some welded transport ships suddenly fractured at around 40 degrees Celsius, despite room-temperature tests showing adequate ductility. Toughness tests determine if a material exhibits a ductile-to-brittle transition with decreasing temperature, represented by a curve showing decreasing impact energy absorption and increasing percentage of shear fracture over a temperature range. The ductile-to-brittle transition occurs as temperature decreases, with ductile fracture at high temperatures and brittle fracture below a certain temperature.
Fracture
This document discusses different types of material fractures: brittle, ductile, fatigue, and creep. Brittle fractures occur with little plastic deformation, while ductile fractures involve significant plastic deformation. Fatigue fractures result from repeated cyclic stresses below the material's tensile strength. Creep fractures happen due to excessive deformation over time under steady loads. The mechanisms of each type are also described, such as Griffith's theory of stress concentrations leading to brittle fractures or dislocation movement causing creep fractures.
Fractures
This document discusses different types of fractures including brittle, ductile, fatigue, and creep fractures. It focuses on explaining brittle fracture in more detail. Brittle fracture occurs with minimal plastic deformation and when the broken pieces are fitted back together, the original shape and dimensions are restored. It is defined as fracture occurring at or below the material's elastic limit. The document then describes Griffith's theory of brittle fracture, which postulates that microcracks are always present in brittle materials and concentrate stress at their tips, leading to crack growth and fracture when the applied energy exceeds the strain energy of the cracks.
What's hot (20)
Analysis of Ductile-to-Brittle Transition Temperature of Mild Steel
Analysis of Ductile-to-Brittle Transition Temperature of Mild Steel
Fracture Mechanics & Failure Analysis:Lecture DBTT
Fracture Mechanics & Failure Analysis:Lecture DBTT
Similar to Creep rahul dhibar
HIGH TEMEPRATURE CREEP OF CERAMICS AND ITS MECHANISM
This presentation gives us the idea about high temperature creep and its mechanism in ceramics
Fracture Mechanics & Failure Analysis: creep and stress rupture
Fracture Mechanics & Failure Analysis: creep and stress ruptureNED University of Engineering and Technology
The document discusses creep and stress rupture behavior of materials at high temperatures. It provides an introduction to creep and stress rupture tests, describing the three stages of creep curves and how applied stress and temperature affect creep behavior. Different deformation mechanisms at high temperatures are discussed, including dislocation glide/creep, diffusion creep, and grain boundary sliding. The document also covers topics such as structural changes during creep, superplasticity, and fracture modes at elevated temperatures.Deformation mechanism.pptx
The document discusses two main mechanisms of plastic deformation: slip and twinning. Slip occurs when one part of a crystal moves over another along specific crystallographic planes and directions. Twinning results when a portion of a crystal takes on a symmetrical orientation to the rest of the crystal, dividing it into two mirrored regions. Factors like external loads, crystal structure, and orientation influence whether slip or twinning occurs. The document also covers different types of material failure like ductile fracture, brittle fracture, creep, and fatigue.
Materials creep
This document discusses creep deformation in materials. It defines creep as time-dependent deformation under an applied load, typically occurring at high temperatures. The main mechanisms of creep are described as bulk diffusion, grain boundary diffusion, and dislocation climb. Classical creep curves consist of primary, secondary, and tertiary creep stages. Factors that influence creep include temperature, stress, grain size, and dislocation movement. Common tests to characterize creep properties are described, such as constant-load tests and stress rupture tests. Design considerations to minimize creep include reducing grain boundaries, using high melting temperature materials, and employing creep data for material selection and inspection intervals.
K.Srinivasulureddy-SNIST-Metallurgy & Material Science-UNIT-2
Metallurgy & Material science, UNIT-2, Sreenidhi, SNIST,K.srinivasulureddy, ductile & brittle fracture, creep,fatigue
Damage tolerance and fracture mechanics
fracture mechanics and damage tolerance .Why do high strain rate, low temperature and triaxial state of stress promote brittle fracture?Method of Crack/Crack Like Defect Analysis
FRACTURE BEHAVIOUR
Griffith proposed that brittle materials contain fine cracks that concentrate stress below the theoretical strength, causing fracture. When a crack propagates, the new surface area requires energy from the released elastic strain energy of the material. Griffith established that a crack will propagate when the decrease in elastic strain energy is equal to or greater than the energy required to create the new surface. The stress intensity factor describes the stress near a crack tip and is used to predict crack propagation. Fracture toughness is the material property describing a material's resistance to crack propagation.
UNIT- V ---TESTING OF MECHANICAL PROPERTIES.pptx
The document discusses various mechanical properties and tests used to evaluate them. It describes the different types of strength materials can exhibit including elastic strength and plastic strength. Factors that can influence mechanical properties are then outlined such as grain size, heat treatment, and temperature. Common deformation mechanisms like slip and twinning are also defined. Different types of mechanical tests are classified as either destructive or non-destructive and specific tests are detailed including hardness, impact, fatigue, compression, and creep tests.
TESTING OF MECHANICAL PROPERTIES
This document provides information on various mechanical tests conducted to evaluate properties of materials, including:
- Plastic deformation testing which evaluates a material's ability to deform permanently under load.
- Hardness testing methods like Brinell, Vickers, and Rockwell which indent materials with an indenter to assess hardness.
- Impact testing like Izod and Charpy tests which determine a material's resistance to sudden load by measuring how much energy is absorbed during fracture.
- Fatigue and creep testing which apply repeated or sustained loads to examine how materials withstand cyclic stresses or deformation over time.
A variety of destructive and non-destructive tests are described that are used industrially and for research to
UNIT- V.pptx
Mechanisms of plastic deformation, dislocation, slip and twinning – Types of fracture – Testing of materials under tension, compression and shear loads – Hardness tests: Brinell, Vickers and Rockwell – Impact test: Izod and Charpy, fatigue and creep test.
CREEP of METALS
Creep is the time-dependent deformation of a material under constant load at high temperatures. It occurs when a material is loaded below its yield strength and the load is maintained for an extended period of time, resulting in plastic deformation that increases over time. Creep can cause failure through rupture or excessive plastic deformation beyond a certain limit. The rate of creep deformation and time to rupture depend on factors like temperature, stress, and material microstructure. Creep becomes significant engineering issue at temperatures over 40% of the material's melting point.
DJJ3213 MATERIAL SCIENCE CHAPTER 3 NOTE.ppt
This document summarizes various mechanical properties and failure modes of materials. It defines physical, thermal, and mechanical properties. Thermal properties describe a material's response to heat, such as heat capacity and thermal expansion. Mechanical properties describe how a material reacts to forces and include properties like toughness, hardness, and elasticity. Failure modes like fracture, fatigue, and creep are also discussed. The document contrasts ductile and brittle failure, and describes how properties vary with temperature for different materials. It provides examples of different fracture surfaces and discusses fracture mechanics concepts.
Component failure in road traffic accident by ayoub el amri
This document discusses various failure modes in materials including brittle versus ductile fracture, fatigue, creep, and stress concentration effects. It explains that brittle materials fracture with little deformation while ductile materials undergo extensive plastic deformation before fracturing. Fatigue failure can occur with fluctuating stresses and involves crack initiation and propagation. Creep is time-dependent deformation that increases with stress and temperature. Stress concentrators like defects and notches reduce a material's strength significantly and can initiate cracks. The document provides examples and diagrams to illustrate different failure mechanisms.
VISCOELASTICITY 1
This document summarizes seminar material on creep and oscillatory testing.
[1] Creep is the slow deformation of a material under constant stress over time and can be divided into primary, secondary, and tertiary stages based on the creep curve. Creep is caused by various mechanisms including dislocation movement and diffusion.
[2] Oscillatory testing involves applying a sinusoidal strain and measuring the stress response to characterize a material's viscoelastic properties like storage and loss moduli.
Impact test
The document reports on an impact test to determine the ductile to brittle transition temperature of steel samples. It describes using Charpy impact testing machines to test samples at different temperatures achieved with boiling water, ice, and room temperature. The results show absorbed energy decreases with lower temperatures, indicating more brittle behavior. The document provides background on fracture types and theories, details the Charpy V-notch impact test procedure and calculations, and lists factors that affect transition temperature.
impact test 10-4
This document discusses impact testing techniques used to evaluate the fracture behavior of materials. It provides background on impact testing and describes the Charpy and Izod impact tests. These tests involve fracturing a notched specimen using a swinging pendulum. The absorbed energy is measured and used to determine the ductile to brittle transition temperature (DBTT) of the material. The DBTT curve shows how absorbed energy and fracture surface morphology change with temperature. Factors that influence the DBTT, such as chemical composition, grain size, and heat treatment are also reviewed. Experimental procedures for conducting impact tests at different temperatures are outlined.
Cracks in-buildings-3568
Cracks in buildings can be either structural or non-structural. Structural cracks indicate failure or overloading of the building, while non-structural cracks do not compromise safety but can allow water penetration. Cracks are classified based on their width as thin, medium, or wide. Their appearance can take different forms like vertical, horizontal, diagonal, or irregular patterns. Cracks have various causes including moisture changes, thermal effects, material issues, foundation movement, or vegetation. The document provides details on specific crack types like plastic shrinkage cracks, settlement cracks, bleeding cracks, and those due to delayed curing or constructional defects. It also discusses cracks in concrete in more depth and suggests measures to prevent or minimize cracking in
5_2018_03_27!12_18_20_PM.pptx
A creep test subjects a specimen to a constant load and temperature over time to measure deformation. There are three creep stages: primary creep where the rate is rapid and decreases over time, secondary creep where the rate is relatively uniform, and tertiary creep where the rate accelerates until rupture. Creep tests are used to determine design parameters like steady-state creep rate and rupture lifetime. Stress rupture tests are similar but impose higher stresses to measure time to fracture. Data from creep tests are used to extrapolate lifetimes at different conditions using methods like the Larson-Miller parameter.
Mechanical Properties.pptx
Ceramics fracture before plastic deformation can occur when subjected to tensile loads. Crack growth in ceramics occurs transgranularly through the grains or intergranularly along grain boundaries. A fractographic study examines the crack propagation path and fracture surface features using various microscopy techniques.
Deformation.pptx
Plastic deformation can occur through two main mechanisms in metals: slip and twinning. Slip occurs when one plane of atoms slides over another within the crystal structure. Twinning involves mirroring part of the atomic lattice next to the undeformed part. Cold working increases the strength and hardness of metals by obstructing the movement of dislocations through mechanisms like strain hardening. Annealing can be used to relieve stresses from cold working and modify mechanical properties by allowing recovery, recrystallization and grain growth processes. Hot working deforms metals above the recrystallization temperature to avoid strain hardening.
Similar to Creep rahul dhibar (20)
HIGH TEMEPRATURE CREEP OF CERAMICS AND ITS MECHANISM
HIGH TEMEPRATURE CREEP OF CERAMICS AND ITS MECHANISM
Fracture Mechanics & Failure Analysis: creep and stress rupture
Fracture Mechanics & Failure Analysis: creep and stress rupture
K.Srinivasulureddy-SNIST-Metallurgy & Material Science-UNIT-2
K.Srinivasulureddy-SNIST-Metallurgy & Material Science-UNIT-2
Component failure in road traffic accident by ayoub el amri
Component failure in road traffic accident by ayoub el amri
Recently uploaded
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, SerbiaTIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEM
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
官方认证美国密歇根州立大学毕业证学位证书原版一模一样
原版一模一样【微信：741003700 】【美国密歇根州立大学毕业证学位证书】【微信：741003700 】学位证，留信认证（真实可查，永久存档）offer、雅思、外壳等材料/诚信可靠,可直接看成品样本，帮您解决无法毕业带来的各种难题！外壳，原版制作，诚信可靠，可直接看成品样本。行业标杆！精益求精，诚心合作，真诚制作！多年品质 ,按需精细制作，24小时接单,全套进口原装设备。十五年致力于帮助留学生解决难题，包您满意。
本公司拥有海外各大学样板无数，能完美还原海外各大学 Bachelor Diploma degree, Master Degree Diploma
1:1完美还原海外各大学毕业材料上的工艺：水印，阴影底纹，钢印LOGO烫金烫银，LOGO烫金烫银复合重叠。文字图案浮雕、激光镭射、紫外荧光、温感、复印防伪等防伪工艺。材料咨询办理、认证咨询办理请加学历顾问Q/微741003700
留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
22CYT12-Unit-V-E Waste and its Management.ppt
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.
Modelagem de um CSTR com reação endotermica.pdf
Modelagem em função de transferencia. CSTR não-linear.
学校原版美国波士顿大学毕业证学历学位证书原版一模一样
原版一模一样【微信：741003700 】【美国波士顿大学毕业证学历学位证书】【微信：741003700 】学位证，留信认证（真实可查，永久存档）offer、雅思、外壳等材料/诚信可靠,可直接看成品样本，帮您解决无法毕业带来的各种难题！外壳，原版制作，诚信可靠，可直接看成品样本。行业标杆！精益求精，诚心合作，真诚制作！多年品质 ,按需精细制作，24小时接单,全套进口原装设备。十五年致力于帮助留学生解决难题，包您满意。
本公司拥有海外各大学样板无数，能完美还原海外各大学 Bachelor Diploma degree, Master Degree Diploma
1:1完美还原海外各大学毕业材料上的工艺：水印，阴影底纹，钢印LOGO烫金烫银，LOGO烫金烫银复合重叠。文字图案浮雕、激光镭射、紫外荧光、温感、复印防伪等防伪工艺。材料咨询办理、认证咨询办理请加学历顾问Q/微741003700
留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECT
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
ACEP Magazine edition 4th launched on 05.06.2024
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Casting-Defect-inSlab continuous casting.pdf
Casting-Defect-inSlab continuous casting. Casting-Defect-inSlab continuous casting. Casting-Defect-inSlab continuous casting. Casting-Defect-inSlab continuous casting. Casting-Defect-inSlab continuous casting. Casting-Defect-inSlab continuous casting. Casting-Defect-inSlab continuous casting. Casting-Defect-inSlab continuous casting
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
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
Computational Engineering IITH Presentation
This Presentation will give you a brief idea about what Computational Engineering at IIT Hyderabad has to offer.
Recently uploaded (20)
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024
Generative AI leverages algorithms to create various forms of content
Generative AI leverages algorithms to create various forms of content
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEM
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEM
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECT
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECT
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
Creep rahul dhibar
- 2. CONTENTS Creep Mechanisms of Creep Effect of High Temperature on Metals Creep Test & After Creep Test Stress Rupture Creep Failure Prevention of creep failure
- 3. • CREEP Creep is a time-dependent process where a material under an applied stress exhibits a dimensional change at high temperature. High temperature progressive deformation of a material at constant stress is called creep. The process is also temperature-dependent. Creep always increases with temperature.
- 4. How Does Creep Occur In materials science, creep is the tendency of a solid material to move slowly or deform permanently under the influence of mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are below the yield strength of the material. Creep can be occur due to different Mechanisms.
- 5. Mechanisms of Creep Different mechanisms are responsible for creep in different materials and under different loading and temperature conditions. The mechanisms include – 1. Bulk diffusion (Nabarro- Herring Creep) 2. Grain boundary diffusion (Coble creep) 3. Grain boundary sliding 4. Dislocation Glide 5. Dislocation creep
- 6. Bulk Diffusion (Nabarro-Herring) Grain Boundary Diffusion (Coble creep) Dislocation climb/creep Diagram:
- 7. Effect of High Temperature on Metals • Lower strength. • Greater atomic and dislocation mobility, assisting dislocation climb and diffusion. • Higher equilibrium concentration of vacancies. • New deformation mechanisms, such as new slip systems or grain boundary sliding. • Recrystallisation and grain growth.
- 8. Creep Test • Usually tensile bar • Dead load applied • Strain is plotted with time • Test usually ends with rapture (creep failure)
- 9. After Creep Test Primary Creep: slope (creep rate) decreases with time. Secondary Creep: steady- state i.e., constant slope. Tertiary Creep: slope (creep rate) increases with time.
- 10. Creep: stress and temperature effects • Time to rupture decreases as imposed stress or temperature increases. • Steady creep rate increases with increase of stress and temperature
- 11. Stress Rupture Stress rupture testing is similar to creep testing except that the stresses used are higher than in a creep test. Stress rupture testing is always done until failure of the material or fracture. Cracking that precedes the rupture of the material can be either transgranular or intergranular.
- 12. Transgranular Creep Fracture (b) More Cleavage
- 13. Intergranular Creep fracture (a) (b)
- 14. Creep Failure (a) (b) (c) (d)
- 15. Creep Failure (Contd.) Power plant pipe creep failure Steam line Turbines in jet engines
- 16. Creep failures are characterized by: • Bulging or blisters in the tube. • Thick-edged fractures often with very little obvious ductility. • Intergranular voids and cracks in the microstructure.
- 17. Prevention of creep failure Reduce the effect of grain boundaries: - • Use single crystal material with large grains. • Addition of solid solutions to eliminate vacancies. Consult Creep Test Data during materials Selection Using materials which are specially resistant to creep: - • Stainless steels • Refractory metals (containing elements like Nb, Mo, W, Ta) • “Super Alloys“ – Co, Ni based (solid solution hardening and secondary phases).
- 18. References • https://www.researchgate.net/profile/Chinedum_Mgbemena3/publication/29201595 3/figure/fig1/AS:497904341454849@1495721053959/A-Typical-Creep-Curve-1.png • Lectures of teacher Dr. Bijay Kumar Show , Department of MME, NIT Durgapur • https://www.ibertest.es/wp-content/uploads/2015/09/IMG_4978_edt.jpg • creep/creepfailurematejjanega1-161206105055.pdf • Mechanical Metallurgy book, GEORGE E. DIETER, JR, McGraw-Hill Book Company • http://glastonburyli.weebly.com/uploads/1/2/7/3/1273419/12_fatigue_of_metals.pdf • https://in.search.yahoo.com/search?fr=mcafee&type=E211IN885G91429&p=stress+ra pture • https://www.slideserve.com/arella/fracture-toughness-fatigue-and-creep