My Exam Notes
  • Home
  • CURRENT AFFAIRS
  • GENERAL AWARENESS
    • Child Category 1
  • BIHAR PSC
  • Home
  • CURRENT AFFAIRS
  • GENERAL AWARENESS
  • BIHAR GK
  • RAJASTHAN GK
  • MECHANICAL NOTES

Monday, August 18, 2014

STRENGTH OF MATERIAL(STRESS AND STRAIN)

 My Exam Notes     9:24 PM     STRENGTH OF MATERIAL     No comments   


                                 STRENGTH OF MATERIAL


STRESS

FORCE PER UNIT AREA OR INTENSITY OF THE FORCE DISTRIBUTED OVER A GIVEN SECTION IS CALLED THE STRESS ON THAT SECTION AND IS DENOTED BY SIGMA.THE STRESS IN A MEMBER OF CROSS SECTIONAL AREA "A" SUBJECTED TO THE AXIAL LOAD"P" IS OBTAINED BY DIVIDING THE MAGNITUDE "P" OF THE LOAD BY THE AREA "A".THE UNIT OF STRESS IS PASCAL OR N/mm^2.



STRESS



The figure above shows the force "P" on the section having cross section area "A". The body will set internal resistance to oppose this force to avoid deformation. The formula for stress is given by Stress=Force/Area.

 In general we come across some different types of stress based on nature of application of force that are discussed below:-


TYPES OF STRESS

COMPRESSIVE STRESS (a)


Opposite of tensile stress is compressive stress. In this force is applied in direction of specimen. Under compressive stress the material's length decreases and its diameter or thickness increases. The compressive stress can be calculated in the similar way as tensile stress is calculated.


Compressive stress=Force/Area.


TENSILE STRESS (b)

The nature of force in tensile stress is away from the body. As in the figure a specimen is subjected to force F across the area A. At any instant the stress induced in the body. Due to tensile stress body suffers elongation in length and subsequently decreases in the diameter.

SHEAR STRESS (c)

It is surface phenomenon. When stress is applied along the surface of body (say in tangential direction along the line of action) the body is said to have shear stress. The figure shows the tangential stress or shear stress along the upper surface.



VOLUMETRIC STRESS


VOLUMETRIC STRESS


When a body is given force from all the directions such that the forces are acting perpendicular to the surface in equal magnitude then the body is said to be under volumetric stress.


Consider a cube as shown in figure, compressive force from all direction is applied and in equal magnitude. This type of stress results in change in volume of body and at the same time retaining the shape of body.



STRAIN IN MECHANICS



When a body is stressed or force is applied on it then the shape of body changes due to stress. The strain in simple words can be explained as changes in shape of body from original shape. The ratio of changed shape to the original shape is called strain. It is unit less quantity. The type of strain depends on the mode of application of force on the body and noticeably deformation or change occurring in the body.

The three types of strains that we study in mechanics are:-
1) Longitudinal strain occurring due to change in length
2) Volumetric strain occurring due to change in overall volume of body.


3) Shear strain which occurs due to deformation of surface.

LONGITUDINAL STRAIN:-


When the body is subjected to change in length by application of external force then it is said to develop longitudinal strain. Let L be the original length and ΔL be the increase in the length by small amount Δ. Then final length developed in the body is L+ΔL on application of force. When there is elongation in the length of specimen after application of force it is called tensile strain. Similarly when the length of specimen decreases it is called compressive strain.

 LONGITUDINAL STRAIN= 
Change in length/Original length = L+ΔL/ L


 VOLUMETRIC STRAIN:-



When a body is deformed from all direction or in other words when the volume of body changes with respect to its original volume then the body is said to be subjected to volumetric strain. Let the initial volume of body be V and let ΔV be change in the volume of body then volumetric strain can be estimated by dividing change in volume to original volume.



VOLUMETRIC STRAIN=
Change in volume/original volume= V+ΔV/ΔV.

SHEAR STRAIN:-



When force acting on the surface of the body then shear strain develops. The shear strain tries to move the upper surface of the body along the direction of force. The magnitude of applied force is responsible for the deformation caused.

Objective questions:-


1) Consider P be the load and A be the area, stress is expressed as


1) A/P

2) A*P
3) P/A
4) P-A

2) Who discovered that stress is directly proportional to strain within elastic limit?


1) Robert hook

2) Mech huge
3) Alferd Nobel
4) None

3) The point at whole weight of body  is assumed to act is called?


1) Moment of inertia

2) Center of buoyancy
3) Center of gravity
4) Center of velocity

4) The ratio of change of volume to original volume is called ?


1) Tensile strain
2) Shear strain
3) Volumetric strain
4) Shear strain

5) Ratio of shear stress to shear strain is called?


1) Poisson's ratio

2) Young modulus
3) Modulus of rigidity
4) None

  • Share This:  
  •  Facebook
  •  Twitter
  •  Google+
  •  Stumble
  •  Digg
Email ThisBlogThis!Share to TwitterShare to Facebook
Newer Post Home

0 comments:

Post a Comment

MY TRAVEL VLOG-Being Tourist

Popular Posts

  • Environment Current Affairs 2019 PDF download | Important Questions |
    Watch video on EXAM FOCUS YOUTUBE CHANNEL. Which city of china in only one with all electric taxis? Taiyuan Shenzhen Jingia...
  • TURBOMACHINES
                    TURBOMACHINE DEFINATIONAND  EXPLANATION A turbo-machine is a device in which energy transfer takes place between ro...
  • #MOST IMPORTANT AUGUST CURRENT AFFAIRS 2018 #PDF link #NOTES #अगस्त करें...
    PDF IS BELOW NOTES - Go Down Notes of August Current Affairs- Navlekha a new platform launched by Google .Google has announced pr...
  • MAY (1-15th) CURRENT AFFAIRS 2019 | MCQ's | EXPLAINED | FREE PDF |
    PDF WILL BE UPLOADED ON 24/05/2019 The newly elected prime minister of Israel is? Benjamin Netanyahu What is the theme of Internati...
  • #SPACE CURRENT AFFAIRS last 6 months #स्पेस/अंतरिक्ष विज्ञान करेंट अफेयर...
    Indian national committee for space research was established in the year 1962 Indian Space Research Organisation was founded in year 19...
  • BANKING CURRENT AFFAIRS | MD, CEO, CHAIRMAN Of BANKS (UPDATED 2019)| MCQ's | static gk
    This POST is on Banking Awareness 2019 with all important National Banks and its MD/CEO/CHAIRMAN with important points to remember for all...
  • ENERGY LOSS IN PIPES, Darcy- weicbach formula, Chezy's formula, minor losses in pipe
    MECHANICAL TIPS AND STUDY MATERIAL When ever there is flow of fluid in pipes there will be resistance which add to energy loss. For our stud...
  • METAL INERT GAS WELDING AND TUNGSTEN INERT GAS WELDING
            TUNGSTEN INERT GAS WELDING (TIG) CHARACTERISTICS IN  BRIEF It is known as GAS TUNGSTEN ARC WELDING (GTAW). Also called Argon arc wel...
  • ECONOMICS CURRENT AFFAIRS (इकोनॉमिक्स) 2019 | JANUARY- JULY (PART 1)
    PLAY VIDEO AND ENJOY LEARNING PDF AT BOTTOM Which among the following company tied up up with India to issue PAN card? MasterCard Vi...
  • ABRASIVE JET MACHINING, WATER JET MACHINING AND ULTRASONIC MACHINING
        ABRASIVE JET MACHINING(AJM) As explained non traditional machining process involves machining action by indirect contact between tool an...

Categories

AUTOMOBILE BASICS BHIHAR PSC BIHAR PSC biology quiz CURRENT AFFAIRS economics FASTEST MACHINES FLUID MECHANICS GEARS GENERAL AWARENESS HEAT AND MASS TRANSFER I C ENGINE JET ENGINES JOB OPENING IN USA MACHINING PROCESSES MANUFACTURING PROCESS MATERIAL SCIENCE mechanical engineering MECHANICAL JOB VACANCY IN INDIA MECHANICAL VIBRATION MISSILES POLITY QUIZ POWER PLANT ENGINEERING RAJASTHAN GK sports STRENGTH OF MATERIAL THERMODYNAMICS TOP COLLEGES TOP SPEED TURBINES WELDING

Pages

  • QUIZ

Featured post

SCIENCE & TECHNOLOGY CURRENT AFFAIRS 2018 (JANUARY - JUNE)विज्ञान प्रौद्...

CBSE (Central Board of indirect taxes) launched which app to check person collecting GST? GST verify National science day was celebrate...

ad code

Copyright © My Exam Notes | Powered by Blogger
Design by Hardeep Asrani | Blogger Theme by NewBloggerThemes.com | Distributed By blogger Templates