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Does stress depend upon strain?


Date: 15 Mar 2016    Group: Education    Category: Exam Questions   

I am completely confused with stress and strain. Whenever I plot a graph between stress and strain I am confused about which one lies on x axis and which one lies on y axis. which one is dependent on the other? According to the relation of stress and strain both are proportional to each other but one is completely dependent on other. I think that stress is applied on the material and then strain is produced. But according to the book it is not correct.
Awaiting clarification from experts.


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Author: Navneet    17 Mar 2016      Member Level: Gold     Points : 5  (Rs 5)    Voting Score: 0

Stress and strain contains the different different properties in different different sections. First of all I want to tell you about strain. STRAIN : When a load acts on the material, it will go under deformation. And the measurement of deformation is known as strain. In case of tensile force, the member elongate. And in case of compressive force, the member shortens in its length. It is measured as the ratio of the change in length to the original length. STRESS:: When load act on a body , the body undergoes deformation. It is also called the change in dimension or in the shape of the body or both. STRESS STRAIN DIG FOR MILD STELL :: The most common method of investigating the mechanical properties of metal is by the tension test. The test is carried out on a bar of uniform cross-section. The straining unit of the testing machine has the necessary arrangement to grip the specimen and to required the axial load. If you have any problem then feel free to ask on ISC.


Author: Madan Lal Mahato    17 Mar 2016      Member Level: Gold     Points : 2  (Rs 2)    Voting Score: 0

Hi Navneet
Here you explain only about the stress and strain that do not give the explanation about the relation between both. My question is that " Does stress depend upon strain" . If not then what is the answer please give explanation on this and like in graph when I draw graph between that both quantity then how will I know that which quantity is a lie on x and y axis .


Author: Adarsh kumar    19 Mar 2016      Member Level: Silver     Points : 4  (Rs 4)    Voting Score: 0

Let me give you the correct relation between stress and strain.
Given below are set of relations that might help you.
1. Stress is directly propotional to strain.
2. This relation gives us young's modulus.
3.The strain usually never occurs untill and unless we stretch it to a point after which strain starts taking place.
4.There is a point called breaking point at which no more strain can be produced and the string breaks.

Hope these points help you derive the relation between stress and strain. Just try to concentrate on young's modulus and you will get the whole concept. You can refer about it in your NCERT textbook.


Author: [Anonymous]    19 Mar 2016      Member Level: Gold     Points : 5  (Rs 5)    Voting Score: 0

I explained it with the help of flow diagram. Please check carefully Mr. MADAN LAL MAHATO. But if you are not satesafied with this then here is the relation between them.

In the Hooke's law ( Young' modulus ) ::

Strain (is directly proportion) Stress.

It has been experimentally established that in many structural materials, up to a certain limit, the strain is directly proportional to the stress producing it. It is usual practice to write that stress is proportional to strain.


Stress/strain= constant=E

Where the constant of proportionality E is known as the modulus of elasticity or Young's modulus.

I hope you are now satisfied with my answer. Following diagram will explain more.
Fell free to ask your questions on India study channels.



Author: Madan Lal Mahato    21 Mar 2016      Member Level: Gold     Points : 0    Voting Score: 0

You explain the whole function but not explaining what is my question. So please explain only my question not whole graph.

Author: Hardik Joshi    05 Apr 2016      Member Level: Silver     Points : 2  (Rs 2)    Voting Score: 0

For the first question:
Stress is proportional to strain and proportionality will change point to point. Up to a limit (called proportionality limit) stress is directly proportional to strain. Beyond that point proportionality is changed.
Now for the second question consider following explanation:
As we used to write function Y = f(X) and plot this function on graph with f(X) on X-axis. Now simply compare Stress – Strain with Y = f(X)
Stress = (Young Modulus) * (Strain)
So stress (Y) is a function of Strain (f(X)) and young Modulus is constant.


Author: [Anonymous]    28 Apr 2016      Member Level: Bronze     Points : 5  (Rs 5)    Voting Score: 0

Q No 1. Whenever I plot a graph between stress and strain I am confused about which one lies on x axis and which one lies on y axis. which one is dependent on the other?
Answer:-
When we draw a stress-strain graph, we normally take Stress along X-axis and Strain along Y-axis. This is only for convenience. (Where do you use your wrist watch ? in left hand or right hand ?).

Q No 2. I think that stress is applied on the material and then strain is produced. But according to the book it is not correct.
Answer :- Nobody can "apply" stress on a material. It seems you do not have a correct idea about stress. We can deform a body. We can apply load on a body, but we cannot apply stress .
Stress is something that is "induced'' in a body. If a 50 kg load is put on your head, you feel pain in your head. (This pain is the result of load applied on your head, but nobody can put ''pain" upon your head.). Note that stress is an invisible feature.
Now, coming back to explanation, when a body is loaded two things happen SIMULTANEOSLY,
1. stress is induced
2. body gets deformed (or strains).
These two things are two aftereffects of loading. Quite interestingly, magnitude of these two things are one-to-one related. This relationship is shown by a stress-strain graph.

Note that, the cause of stain is NOT stress and vice versa. When stress occurs, strain also occurs thats all.



Author: Ganesh    06 Jun 2016      Member Level: Silver     Points : 2  (Rs 2)    Voting Score: 0

Yes, Stress is depends upon strain. This relation is easily explained through Hooke's law. This law states that "the strain in a solid is proportional to the applied stress within the elastic limit of that solid". After elastic limit the body start to deform.

Strain is the cause and stress is the effect. When a force is applied to a body, after elastic limit the body starts to deform. These deformations or change in dimensions known as strain. But stress is the internal resisting force per unit area of the cross section.






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