This document contains 18 problems related to dynamics of machines including vibration of systems, critical speeds of shafts, torsional vibrations, and damping characteristics. The problems involve calculating properties like natural frequency, damping ratio, logarithmic decrement, and critical speeds for systems with masses, springs, dampers, and shafts experiencing bending and torsional vibrations. Solutions require applying concepts of free, forced, and damped vibrations as well as mechanics of materials equations for stress, strain, and deflection of shafts.
Dynamic Analysis of Rotating stepped Shaft with Transverse CrackIJERA Editor
This study describes dynamic analysis of stepped shaft with single crack of EN8 material. The objective is to compare results of healthy stepped shaft and single cracked stepped shaft for different crack depth ratios at variable rpm .The dynamic analysis is carried out by using finite element method. Obtained results from analysis are benchmarked from literature. It is observed that there is 84.80% increase in amplitude of acceleration of cracked shaft. Also modal analysis of shaft has been carried out to know effect on natural frequencies of healthy shaft and cracked shaft. The effects of crack depth, crack length & RPM on amplitude of acceleration are obtained.
Study on Vibration Reduction Effect of the Rail Vehicle with Axle Dynamic Vib...IJRES Journal
To reduce the vertical vibration of the vehicle, the vehicle model including the axle dynamic
vibration absorber is established, and the vertical vibration acceleration spectrum of the wheel, the steering
frame and the body is obtained by numerical simulation. The vibration reduction effect of the dynamic vibration
absorber is analyzed. The results show that the axle dynamic vibration absorber not only has a good vibration
reduction effect on the wheel, but also has an important effect on the vertical vibration of the bogie and the
vehicle body.
Dynamic Analysis of Rotating stepped Shaft with Transverse CrackIJERA Editor
This study describes dynamic analysis of stepped shaft with single crack of EN8 material. The objective is to compare results of healthy stepped shaft and single cracked stepped shaft for different crack depth ratios at variable rpm .The dynamic analysis is carried out by using finite element method. Obtained results from analysis are benchmarked from literature. It is observed that there is 84.80% increase in amplitude of acceleration of cracked shaft. Also modal analysis of shaft has been carried out to know effect on natural frequencies of healthy shaft and cracked shaft. The effects of crack depth, crack length & RPM on amplitude of acceleration are obtained.
Study on Vibration Reduction Effect of the Rail Vehicle with Axle Dynamic Vib...IJRES Journal
To reduce the vertical vibration of the vehicle, the vehicle model including the axle dynamic
vibration absorber is established, and the vertical vibration acceleration spectrum of the wheel, the steering
frame and the body is obtained by numerical simulation. The vibration reduction effect of the dynamic vibration
absorber is analyzed. The results show that the axle dynamic vibration absorber not only has a good vibration
reduction effect on the wheel, but also has an important effect on the vertical vibration of the bogie and the
vehicle body.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
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Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
1. ME8594 - DYNAMICS OF MACHINES
UNIT –III (Part –B)
Prepared By: N. E. Godwin Pithalis Page 1
1. The mass of single degree damped vibrating system 7.5 kg and makes 24 free oscillations in 14
seconds when disturbed from its equilibrium position. The amplitude decreases to 0.25 of its initial
value after 5 oscillations. Determine (i) the spring stiffness (ii) logarithmic decrement (iii) damping
factor (DEC-2012)
2. (i) Derive an expression for the frequency of free torsional vibrations for a shaft fixed at one end
and carrying a load on the free end. (DEC-2012)
(ii) What is meant by torsionally equivalent length of a shaft as referred to a stepped shaft? Derive the
expression for the equivalent length of a shaft which has several steps. (DEC-2012)
3. A vibrating system consists of a 5 kg mass, a spring with constant of 3.5 N/mm and a dashpot with
damping coefficient of 100 N.sec/m. Determine, (i)Damping factor (ii)Damped Natural Frequency
(iii)Logarithmic decrement (iv)Ratio of two successive amplitudes. (MAY2008)
4. The following data refer to a shaft mounted in long bearings:
Length of the shaft = 1.2 m, Diameter of the shaft =14 mm, Mass of a rotor at midpoint of the shaft
=16 Kg, Eccentricity of the center of mass of rotor from the center of rotor =0.4 mm
Modulus of elasticity of shaft material =200 GN/m 2
, Permissible stress value of shaft material =70 X
10 6
N/m 2
,Determine the critical speed of the shaft and the range of speed over which is unsafe to run
the shaft .Assume the shaft to be mass less. (MAY2008)
5. A shaft 1.5m long supported in flexible bearings at the ends carries two wheels each of 50 kg mass. One
wheel is situated at the center of the shaft and the other at distance of 375 mm from the center towards left. The
shaft is hollow of external diameter 75 mm and internal diameter 40 mm. The density of the material is 7700
kg/m3
and its modulus of elasticity is 200 GN/m2
. Find the lowest whirling speed of the shaft, taking into
account the mass of the shaft.
6. A steel shaft ABCD 1.5 m long has flywheel at the ends A and D the mass of the flywheel A is 600 kg and
has a radius of gyration of 0.6m the mass of the flywheel D is 800 kg and has a radius of gyration of 0.9 m the
connecting shaft has a diameter of 50 mm for the portion AB which is 0.4 m long and has a diameter of 60mm
for the portion BC which is 0.5 m long and has a diameter of d mm for the portion CD which is 0.6 m long.
Determine (i) The diameter ‘d’ of the portion CD so that the nodes of the torsional vibration of the system will
be at the centre of the length BC and (ii) The natural frequency of the torsional vibration , The modulus of
rigidity for the shaft material is 80 GN/m2
(MAY-2014)
2. ME6505 - DYNAMICS OF MACHINES
UNIT –III (Part –B)
Prepared By: N. E. Godwin Pithalis Page 2
7. Determine: (i) the critical damping co-efficient, (ii) the damping factor, (iii) the natural frequency of damped
vibrations, (iv) the logarithmic decrement and (v) the ratio of two consecutive amplitudes of a vibrating system
which consists of a mass of 25 kg, a spring of stiffness 15 KN/m and a damper. The damping provided is only
15% of the critical value. (DEC-2010)
8. A shaft of length 1.25 m is 75 mm in diameter for the first 275 mm of length, 125 mm in diameter for the
next 500 mm length, 87.5 mm in diameter for the next 375 mm length and 175 mm in diameter for the
remaining 100 mm of its length. The shaft carries two rotors at two ends. The mass moment of inertia of the
first rotor is 75 kgm2
whereas of the second rotor is 50 kgm2
. Find the frequency of natural torsional vibrations
of the system. The modulus of the rigidity of the shaft material may be taken as 80 GN/m2
.
(DEC-2010)
9. (i) A machine weighs 18 kg and is supported on springs and dashpots. The total stiffness of the springs is 12
N/mm and damping is 0.2 N/mm/s the system is initially at rest and a velocity of 120 mm/s is imparted to
the mass. Determine (i) the displacement and velocity of mass as a function of time. (ii) The
displacement and velocity after 0.4s. (DEC-2009) (DEC-2013) 12
(ii) Describe the types of vibration with simple sketch (DEC-2013) 4
10. A torsional system is shown in fig. find the frequencies of torsional vibrations and the positions of
the nodes also find the amplitudes of vibrations. Take G = 84 x 109
N/m2
.
(DEC-2013)
11. The flywheel of an engine driving a dynamo has a mass of 180 kg and a radius of gyration of 30 mm. The
shaft at the flywheel end has an effective length of 250 mm and is 50 mm in diameter. The armature mass is 120
kg and its radius of gyration is 22.5 mm. The dynamo shaft is 43 mm diameter and has 220 mm of effective
length. Calculate the position of node frequency of torsional vibration. (MAY -2011)
12. A vibrating system consists of a mass of 20 kg, a spring of stiffness 20 KN/m and a damper. The damping
provided is only 30% of the critical value. Determine the damping factor, critical damping co-efficient, natural
frequency of damped vibrations, logarithmic decrement and the ratio of the consecutive amplitudes.
(MAY -2011)
3. ME6505 - DYNAMICS OF MACHINES
UNIT –III (Part –B)
Prepared By: N. E. Godwin Pithalis Page 3
13. A shaft 50 mm diameter and 3 meters long is simply supported at the ends and carries three point loads of
1000 N, 1500 n and 750 N at 1 m, 2 m and 2.5 m respectively from the left support. The young’s modulus for
the shaft material is 200 GN/m2
. Find the frequency of transverse vibration. (DEC-2011)
14. A vertical shaft of 5 mm diameter is 200 mm long and is supported in long bearings at its ends. A disc of
mass 50 kg is attached to the centre of the shaft. Neglecting any increase in stiffness due to the attachment and
the disc to the shaft, find the critical speed of rotation and the maximum bending stress when the shaft rotating
at 75% of the critical speed. The centre of the disc is 0.25 mm from the geometric axis of the shaft. Take E =
200 GN/m2
. (DEC-2011, MAY-2013, DEC-2014)
15. A shaft is simply supported at its ends and is of 40mm in diameter and 2.5 m in length. The shaft carries
three point loads of masses 30kg, 70 kg and 45 kg, at 0.5m, 1m, 1.7m respectively from the left support. The
weight of the shaft per meter length is given as 73.575N. The young’s modulus for the material of the shaft is
200 GN/m2
. Find the critical speed of the shaft. (DEC -2009)
16. (i) A 5 kg mass attached to the lower end of a spring, whose upper end is fixed, vibrates with a natural
period of 0.45 sec. Determine the natural period when 2.5 kg mass is attached to the midpoint of the same
spring with the upper and lower ends fixed. (6)
(ii) A vibrating system is defined by the following parameters m =3kg, k = 100 N/m, C = 3 N-sec/m. Determine
the damping factor, the natural frequency of damped vibration, logarithmic decrement, the ratio of two
consecutive amplitudes and the number of cycles after which the original amplitude is reduced to 20 percent.
(10) (MAY-2012)
17. A machine of mass 75 kg is mounted on springs and is fitted with a dashpot to damp out vibrations. There
are three springs each of stiffness 10 N/mm and it is found that the amplitude of vibration diminishes from
38.4mm to 6.4 mm in two complete oscillations. Assuming that the damping force varies as the velocity,
determine(i) The resistance of the dashpot at unit velocity (ii) The ratio of the frequency of the damped
vibration to the frequency of the undamped vibration and (iii) The periodic time of the damped vibration.
(MAY-2013)
18. A vertical steel shaft 15mm diameter is held in long bearings 1m apart and carries at its middle a disc of
mass 15kg. The eccentricity of the centre of gravity of the disc from the centre of the rotor is 0.3 mm. The
modulus of elasticity for the shaft material is 200 GN/m2
and the permissible stress is 70MN/m2
. Determine (i)
The critical speed of the shaft and (ii) The range of speed over which it is unsafe to run the shaft. Neglect the
mass of the shaft. (DEC-2014)