Your question have no clear response

you need to implement the jacobian matrix in abaqus (DDSDDE) which is : d-stress/d-Strain. Therefore, the jacobian will depend on the stress-strain relation you want implement.

you can download the abaqus umat file in the link which give some examples

http://webcache.googleusercontent.com/search?q=cache:9n4Ko4d5T4sJ:www.researchgate.net/file.PostFileLoader.html%3Fid%3D54fdbf46ef9713e3798b4567%26assetKey%3DAS%253A273727718133779%25401442273181845+&cd=1&hl=fr&ct=clnk&gl=fr

Dear Ridha Hambli

Thanks for your reply.

I am already having the abaqus umat file for which you have provided the link. In this file their is a formulation and umat program for Isotropic Hardening under cyclic loading. My problem is I want to understand the derivation of the formulation given in this file. Please have a look at this formulation and see if you can help me in deriving the jacobian for isotropic hardening under cyclic loading.

With warm regards

Rajwinder Singh

You need to study any book on Nonlinear finite element method, if you want to learn detailed derivation. One of the reference is NONLINEAR CONTINUUM MECHANICS FOR FINITE ELEMENT ANALYSIS by Javier Bonet and Richard D. Wood.

Apart from it, Mr. Ribha has already shared the link for UMAT.

In addition to the book by Bonet and Wood, please see another excellent book by Dunne and Petrinic.  This one has some example problems with software.

MR. Reddy I have already solved the problem using the same book that you are referring. Its indeed a very good book. By the way thanks for your reply.

Dear all

The link of abaqus umat file is not working, can anybody provide working link please?

Many thanks,