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I have a question about deformation gradient in VUMAT.

When I use one element, Vumat works well and there is no any problem. Initially, only the diagonal part of deformation gradient is one, the others are zero. However, the problem is when several elements are considered, all the components of deformaiton gradient are equal to one at very beginning.

Hello everyone,

Here is the problem I have: I'm modeling the geometry of a simple straight edge crack in a 2D elastic medium using Abaqus. I assume plain stress conditions. The crack makes an angle with the horizontal, is small enough to be considered as embedded in an infinite domain (ratio crack length/size of domain < 1/10) and I apply a vertical compressive load on top of my domain. I fixed one point in displacement at the bottom of it and the whole bottom edge is constrained not to move vertically.

hi, i want yield stress and plastic strain data for aluminium and epoxy resin.actually i m doing project on composites.....

Hi, Matlab experts !

Did someone work with Prof. Houck's paper (A genetic algorithm for function optimization: A Matlab implementation, 1995) on the genetic algorithm ?.

In his paper he proposes 3 online tutorials (gademo1.m; gademo2.m; gademo3.m) for working with the function "ga" in Matlab but it's all for Matlab 5. This function syntax has changed considerabily in Matlab 7. The key point is that we cannot define "bounds" which is a matrix of upper and lower bounds on the variables with Matlab 7.

So how Matlab 7 deals with this problem ?

The Computational Physics group in the Atmospheric, Earth, and Energy Division at the Lawrence Livermore National Laboratory (LLNL) is solicitating applications for three postdoctoral appointments in the following areas. To access the full description and application instructions, please visit http://jobs.llnl.gov and search for the job numbers below:

008351: geomechanics of fluid-induced fault activation

008374: dynamic impacts into granular materials

008375: mechanics of dynamic impact and penetration into ceramics

*This issue of the Journal Club has been prepared as a group by Ankush Aggarwal, Mo Bai, Mainak Sarkar, and Jee E Rim, and with comments and suggestions from Bill Klug .