Hello,
I am a new user of Abaqus and its libaray UMAT. Since I need to perform some CPFEM simulations, I used Huangs's UMAT code. I tried to execute the example input file and to replicate the copper case study repoterted in: "A USER-MATERIAL SUBROUTINE INCORPORATING SINGLE CRYSTAL PLASTICITY IN THE ABAQUS FINITE ELEMENT PROGRAM". The simulation exits with error when using the example input file due to numerical singularities and when I create my own input file I'm not able to obtain plastic strain and I only have elastic response for any displacement and pressure value. Something is wrong but i can not figure it out.
Has someone encoutered this problem?
Does anyone have any idea what the problem might be?
Thanks in advance for your help.
Dear Paolo Antonioni,
You may want to review the data presented below:
I wanted to use Huang's UMAT to model crystal plasticity. I tried the code with the copper example in the article " A USER-MATERIAL SUBROUTINE INCORPORATING SINGLE CRYSTAL PLASTICITY IN THE ABAQUS FINITE ELEMENT PROGRAM ". ... But I think there is something I did wrong because when I run the simulation for any pressure or displacement on the copper bar, I only have an elastic response. Can anyone tell me what can be the problem or help me with a good input file I can then use? Thanks in advance for your help. Abaqus. Crystal Plasticity.
https://www.researchgate.net/post/Can_anyone_help_me_to_implement_properly_Huangs_UMAT_for_single_crystal_plasticity_on_Abaqus
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User Material Subroutine for Single Crystal Plasticity
A User Material (UMAT) subroutine that models the deformation of single crystals which undergo plastic deformation can be downloaded. It is suitable for use with the commercial finite element code ABAQUS. The UMAT was originally written in 1991 by Dr. Yonggang Huang, now a professor at Northwestern University, and was modified in 1997 by Jeffrey W. Kysar, now a professor at Columbia University in New York City. Both were in the research group of Professor James R. Rice at Harvard University at the time of their contributions to the code.
The authors assume no responsibility for errors or omissions in the software or documentation available from this web site. Unfortunately due to time constraints, the authors are not able to respond to requests for assistance on using the software.
Electronic copies of the documentation for the UMAT along with appropriate bibliographic citations are found below:
Huang, Y. (1991). "A user-material subroutine incorporating single crystal plasticity in the ABAQUS finite element program, Mech Report 178", Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts.
Kysar, J. W. (1997). "Addendum to 'A user-material subroutine incorporating single crystal plasticity in the ABAQUS finite element program, Mech Report 178'", Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts.
Click here to download a sample ABAQUS input file for the UMAT. It is suitable for ABAQUS v5.6, however recent versions of ABAQUS have routines which will automatically update the input file to be suitable for the current version.
Click here to download only the UMAT Fortran code.
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Error when trying to run simulation with Huang's UMAT using a single element:
https://stackoverflow.com/questions/70161888/error-when-trying-to-run-simulation-with-huangs-umat-using-a-single-element
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Simplified Finite Elements
Tutorial: Write a simple UMAT in ABAQUS Introduction UMAT stands for User Material.
https://simplifiedfem.wordpress.com/about/tutorial-write-a-simple-umat-in-abaqus/
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1.1.31 UMAT User subroutine to define a material's mechanical behavior.
Product: ABAQUS/Standard
Warning: The use of this subroutine generally requires considerable expertise. You are cautioned that the implementation of any realistic constitutive model requires extensive development and testing. Initial testing on a single-element model with prescribed traction loading is strongly recommended.
References
- “User-defined mechanical material behavior,” Section 20.8.1 of the ABAQUS Analysis User's Manual
- “User-defined thermal material behavior,” Section 20.8.2 of the ABAQUS Analysis User's Manual
- *USER MATERIAL
Overview
https://classes.engineering.wustl.edu/2009/spring/mase5513/abaqus/docs/v6.6/books/sub/default.htm?startat=ch01s01asb31.html
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Thanks for your answer Len Leonid Mizrah and the helpful sources.
I had already consulted the post in the link: https://www.researchgate.net/post/Can_anyone_help_me_to_implement_properly_Huangs_UMAT_for_single_crystal_plasticity_on_Abaqus without solving my problem. I also tested the files present in on of answers but when I run the input file I have numerical problems in some of the nodes and I think it due to the boundary conditions. The same thing happens when I use the original input file.
Hi Paolo Antonioni,
I think your code might have some errors, and you need to recheck it. I can recommend you some packages that will help you in modeling the plasticity of isotropic materials and composite materials with the UMAT subroutine:
https://www.youtube.com/watch?v=96sfwnvLHkA
https://caeassistant.com/product/umat-subroutine-vumat-subroutine/#1576702296965-155e826a-9aae
https://www.youtube.com/watch?v=Go8entmePiQ
https://caeassistant.com/product/advanced-umat-subroutine/
Also, if you need any example files, visit this website; you just need to search your keywords:
https://caeassistant.com/example-bank/
Best wishes.
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