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Cyclic Plastic Dissipation Calcualtion in UMAT

Submitted by Mehdi Naderi on

During Fatigue temperaure of materials increases due to plastic deformation.  I am trying to calcualte plastic dissipation in UMAT and use it as heat source in HETVAl to get temperature rise.  I do not know how to add plastic dissipation calculation in UMAt.  I am wondering if some body  give me an example which is done close to what I want to do.

WhatDifference:same stress-strain curve for linear elastic material with nonlinear young's modulus and hyperelastic material

Submitted by Xiaogai Li on

Hi everyone,

Now I am trying to implement Ogden model in Comsol Multiphysics, but I had some problem.

Then I realized that in Comsol, it's possible to implement a nonlinear young's modulus.

But I am a little confused.

If you have a nonlinear Young's modulus, in the stress-strain curve, E is the tangent of this curve.

For hyperelastic material, let's say Ogden material. It's usually a nonlinear stress-strain curve as well.

combining UMAT and UEL

Submitted by hadi on

I am trying to combine UMAT and UEL in my Abaqus calculation to simulate crack propagation by using a damage criterion. My UMAT calculates the damage variable in each time increment and whenever the damage variable violates the damage criterion in one or more elements, I should seperate the damaged element(s) via XFEM theory which can be implemented into a UEL code; therefore, I should use both UMAT and UEL in my calculation. Is there any way to combine these two codes together?

Finite Element Discretization in Time Direction

Submitted by Jayadeep U. B. on

In the finite element analysis of a transient problem, the usual procedure is to discretize the space (domain) using finite elements, while in the time direction, a time-stepping scheme based on finite differences is used. Is it possible to use a finite element type discretization in time also?  Is there any work done in this manner?