Learning Forum

[zzang3132]

Hi. I study mechanical engineering.

I’m trying to analysis nonlinear structure.

I have a yield strength and tensile strength value.

But, when i use bilinear, i need a tangent modulus.

how can i get the tangent modulus?

is there a equation or formula?

please share your skill and information.

[peteroznewman]

Set the Tangent Modulus to 0.0 for a conservative analysis.
Once you use Plasticity in the material model, you need to know another material property: Elongation (at Break).
Elongation is the value of Strain when failure occurs in a simple tensile test.
Without Plasticity, you may have used Ultimate Tensile Strength to calculate a Safety Factor for the design.
With Plasticity, and a zero Tangent Modulus, the stress will not go above Yield, so you need a new Safety Factor.
Safety Factor = Elongation/(Equivalent Total Strain)
A Safety Factor < 1.0 predicts failure.