basic Stress Strain ?
basic Stress Strain ?
(OP)
Hi,
This is a very basic question on stress strain so I am hoping that I will find the answer.
I have conducted a tensile test and have the load values in Newtons.
I want to plot the results in stress/ strain graph
I have calculated the different engineering stresses with the formula:S= load/ cross sectional area.
Then I have calculated the strain- e= change in length/original length.
The issue that I have( and I maybe missing the point here)is that I have various values for stress but only 1 value for strain ie 0.3. So how do I plot the different values for stress against 1 value for strain.
Do I have to carry out a calculation which includes the elasticity modulus to get different strain values?
I then have to calculate the true stress/ strain when I have carried this out.
This is a very basic question on stress strain so I am hoping that I will find the answer.
I have conducted a tensile test and have the load values in Newtons.
I want to plot the results in stress/ strain graph
I have calculated the different engineering stresses with the formula:S= load/ cross sectional area.
Then I have calculated the strain- e= change in length/original length.
The issue that I have( and I maybe missing the point here)is that I have various values for stress but only 1 value for strain ie 0.3. So how do I plot the different values for stress against 1 value for strain.
Do I have to carry out a calculation which includes the elasticity modulus to get different strain values?
I then have to calculate the true stress/ strain when I have carried this out.





RE: basic Stress Strain ?
Then do you have the curve of load vs displacement from you tensile test? If yes, plot of engineering stress/strain is very straightforward, just use original cross section and length.
Based on engineering stress/strain curve, in theory, you can Plot out true stress/strain, at least until necking happens. After necking, it is not correct any more because loading is not axial, but a tri-state stress.
RE: basic Stress Strain ?
If I understand your post correctly, you have many stress measurements, but only 1 strain measurement, i.e. the strain to failure which is 0.3? You have to continuously measure the strain during the test in order to create a stress-strain plot. Strain is measured using an extensometer, or by using the cross-head displacement.
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RE: basic Stress Strain ?
http://www.keytometals.com/Articles/Art43.htm