research

My name is hexu,a graduate, my major is solid mechanics,eapecially micromechanics,also study finite element method.

Dear all!

For quite a long time (not full time though)  I've been trying to get a multi-surface plasticity model running, without finally successing. Yet.

I am coding the algorithm Simo & Hughes give in "Computational Inelasticity" in Box 5.2a-c  into an Abaqus-umat written in fortran. I apply it for perfect plasticity (at the moment), therefore it is simplified from the original.

I am working on reinforced fiber composites, after modelling the unit cell(R.V.E) of the composite various boundary conditions are applied. After this result is obtained. The results are element(elements produced after meshing)-oriented. I want the stress as a whole on the whole unit cell. I have tried measuring the forces on the faces by taking the cumalative of nodal forces on each face. However, the common edges creates a problem. Can you suggest any other methos of calculating the stress on whole body.

The assignment:Determination of crack propogation direction for CT specimen using different theories such as MTS,MTPS,Del-criteria,T-criteria,Ip theory

using ansys multiphysics

1) What are the boundry condition to be used for above criteria

2) How to take care of mixed mode loading

Shannon-type expected information gain can be used to evaluate the
relevance of a proposed experiment subjected to uncertainty. The
estimation of such gain, however, relies on a double-loop integration.
Moreover, its numerical integration in multi-dimensional cases, e.g.,
when using Monte Carlo sampling methods, is therefore computationally
too expensive for realistic physical models, especially for those
involving the solution of partial differential equations. In this work,
we present a new methodology, based on the Laplace approximation for the
integration of the posterior probability density function (pdf), to
accelerate the estimation of the expected information gains in the model
parameters and predictive quantities of interest. We obtain a

Hi

I used coupled temperature displacement analysis in Abaqus for simulation hot forming sheet but obtain negative temperature in coupled temperature displacement analysis in Abaqus.

I think maybe my contact or mesh is not correct.

my step type: Dynamic, Temp-disp, Explicit 

mesh type: S4RT

contact type: surface to surface(Explicit) Penalty method contact  with termal conductance

Please help me to solve this problem.