Bilinear Isptropic Hardening ? Please Help.

[Fhdak88]

Dear All,

I am running a Impact (Dynamic/ Explicit) Simulation, A Modeling of Charpy Impact Test; A striker hitting a specimen. However, I am kind of having problem in setting the material Properties.

The Material Properties should be :

Steel Alloy 4140 with Young’s modulus of elasticity 207 GPa, yield strength of 655 MPa, Possions ratio of 0.3 and ultimate tensile strength 1020 MPa at room conditions (25 °C). USE bilinear isotropic hardening (a piecewise linear plasticity model).

Now, I know how to insert simple properties such as Density, Elasticity and Plasticity. But i am blank about 'Bilinear Isotrpoic Hardening'..

My question is a simple one:

Can someone tell me how and where should i insert these properties in the Material Properties (Step by Step)?

Thank you,
Fhd

 

[pirs]

Hello Fhd.

Let me see if I can help you out here.

If I understand correctly, you want to add a second linear branch to your material constitutive relation, which would correspond to hardening.

I think the answer is to simply add a second line to the *Plastic command, where you introduce the ultimate strength and strain (which you don't mention in your question, i'll name it eu).

Example:
*Plastic
655, 0
1020, eu

Further, maybe you should consider using true stress and strain definition, which I am not sure you considered so far.

Good luck,
Pirs

 

[pirs]

Adding to my previous answer, eu is defined as the plastic strain, so you should subtract your yield strain from the ultimate strain.

Pirs