
Re: Tangent Modulus
Bill McEachern Aug 13, 2015 8:49 AM (in response to Thulani Sobekwa)as a first approximation.....plastic strain/(ultimate stressyield stress)

Re: Tangent Modulus
Janko Stellaard Aug 13, 2015 9:03 AM (in response to Thulani Sobekwa)indeed, it is a simplified linearized representation of the stressstrain curve behind the yield point.
I see in the literature that the bulkmodule (K) is often used to calculate the tangent module.
On the bottom of the next wikipage (see table), you can find how to calculate the bulkmodule (K) from the Youngsmodule (E) and poissons ration (nu): K = E / 3*(1  2*nu)
Young's modulus  Wikipedia, the free encyclopedia
Janko Stellaard
Cadmes BV
The Netherlands

Re: Tangent Modulus
Thulani Sobekwa Aug 17, 2015 2:18 AM (in response to Janko Stellaard)Thanks,
It seems doable. I will give it a try.

Re: Tangent Modulus
Thulani Sobekwa Aug 20, 2015 4:20 AM (in response to Janko Stellaard)Hi Janko,
I did perform a nonlinear study with Tangent Modulus defined on the material properties. I duplicated the same study, but I removed Tangent Modulus on material properties. When I run the study without the Tangent Modulus I still get the same results. Does this mean the Tangent Modulus is useless on nonlinear study?

Re: Tangent Modulus
Janko Stellaard Aug 20, 2015 4:35 AM (in response to Thulani Sobekwa)The tangent modulus is only necessary if the material yields. So if no yielding occurs, the results will be the same.
Janko Stellaard
Cadmes BV
The Netherlands


Re: Tangent Modulus
Janko Stellaard Aug 20, 2015 5:58 AM (in response to Thulani Sobekwa)If the stressstrain curve is defined, it will automatically select the curve instead of the tangent modulus. The tangent modulus can only be used in Nonlinear studies, so it can never be useless, unless a SScurve is defined.
The stressstrain curve that you need to define is only the part after yielding.
Go to the strain plot, and select 'plastic strain' under the advanced options, there you should see differences then.
Janko Stellaard
Cadmes BV
The Netherlands



