Hi,
We are using the user subroutine UMAT in ABAQUS for varying the material properties in a thin plate. For any static analysis this subroutine is working perfectly fine. However, while using UMAT during natural frequency extraction, ABAQUS is not completing the analysis and is giving a very vague following error message in the log file:
I have funding for software development to provide a UMAT interface in the parallel versions of the code from Smith I.M. and Griffiths D.V. "Programming the Finite Element Method", 4th Edition, Wiley, 2004.
I would be interested to hear about any open source UMATs available for download. I'd also like to hear from anyone who might like to use their closed source UMATs in a parallel environment.
The funding has been awarded by the UK National HPC Service HECToR to encourage the greater use of HECToR for Structural Engineering.
Dear all,
I have several questions about how to use existing constitutive law of material to code UMAT in Abaqus. I have carried out experiment for several powder materials, including metal, ceramic, polymer powders. The powder aggregate is compacted in a cylindrical die. After the compaction, relationships between axial stress and axial strain, radial stress and axial strain are obtained. The material under such condition is always treated as elastic plastic material.
Hi
***ERROR: THE SOLUTION-DEPENDENT STATE VARIABLE INDEX MUST BE AN INTEGER",
this is a error which pops out when i try to run Huang's single crystal UMAT. Do anybody have experienced the same kind of error
Karthic
Dear All,
I think that many students are looking for some tutorials about writing a UMAT in ABAQUS.
You can find a comprehensive tutorial for elastic problems.
This file contains:
• Motivation
• Steps Required in Writing a UMAT or VUMAT
• UMAT Interface
• Examples
Example 1: UMAT for Isotropic Isothermal Elasticity
Example 2: UMAT for Non-Isothermal Elasticity
Example 3: UMAT for Neo-Hookean Hyperelasticity
Here is a UMAT using an elastic viscoplastic model for soil
Modifed Cam-clay model coupled with viscosity.
A user-defined subroutine in ABAQUS for viscous soils.
Introduction:
The ABAQUS subroutine is for viscous soils, which
usually have the following characteristics.
Hi, friends,
Now, I am implementing the non-local continuum theory in ABAQUS through UMAT programming.
Unfortunately, I have been obstacled by the following question:
On one hand, in non-local continuum theory, the non-local strain of every particular integration point is determined by the global strain field all over the specimen.
Hello,
Now I want to simulate the change Young's modulus due to the mechanical stimulus in soft tissue. In our soft tissue(scaffold) we have seeded living cells and these cells produce the collagen fiber type-II which could be interpreted as change of Young's modulus. The Young's modulus of neighbour elements of the cells have to change depending on the Young's modulus of former elements like domino.
I have two constitutitve equations programmed in UMAT i. e. for scaffold and for fibers and they run good.
I am working with shape memory alloys (nitinol), and am in that respect investigating fracture behaviour of NiTi, using, among other things, simulations in ABAQUS. ABAQUS doesn't have a material model that include plasticity unless you pay for it. I am wondering if anyone have implemented either of the following models as a UMAT, and if you are willing to share the code with me.
The models I am interested in are:
