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UMAT subroutine in ABAQUS for elasto-plastic cyclic loadings

Submitted by bojan on

I want to implement the elasto-plastic model for cyclic loadings (I suppose
something like chaboche) into the UMAT subroutine in my ABAQUS  model ,
but I haven't enough knowldge for do this. I read some book like mechanichs of solid materials but i don't understand how to implement my constitutive law into the subroutine. until the load is static i don't have many problems, but when i work with cyclic load I'm non able to generate a cyclic increments of plastic behaviou.

Modelling Hyper-elastic Plate Using ABAQUS

Submitted by J Mahmud on

Dear All,

For months, I have tried to model a plate with circular hole which has the properties of hyper-elastic material (Ogden) but the results are still not promising compared to literature (Y Basar 1998).  The main problems are:

1. The maximum load I succeeded to apply was q=26, while literature had applied load up to 90. For q > 26, the analysis will terminate with errors such as too many attempt, excessive distortion etc.

2. The results I get for q<26 are not the same as literature. 

I attach my best result for your viewing.

Abaqus implicit, rigid body-deformable body contact, negative dot product

Submitted by Andreas Burger on

Hello,



I am running a simulation where I have a rigid body (shell elements) pushing into a deformable part.  Unfortunately, the simulation aborts with the following error:



The dot product -0.19758 cannot be negative for element 30050 instance xzy with record ID 844 at step 2 inc 1 kitgen 5.



This element (C3D4H) belongs to the deformable part and is within the body, so no not close to the contact at all.  At the point where the simulation aborts, this element is not deformed and the stress is basically 0 (E-6).

process simulation using abaqus

Submitted by rahimso on

Hello eeryone here.I am very new user here but before signing up here i saw a numbers of interestig post .Here i have a problem .I am asked to simulate a cutting process with abaqus.A cutting tool cuttong through a work piece .The objective is to check the variation of the work piece profile based on the change on tool change.

Paul Germain passed away

Submitted by Frederic Dias on

The present and past officers of the International Union for Theoretical and Applied Mechanics, the present and past presidents of the French National Committee for Mechanics, sadly announce the death of




Professor Paul Germain,


Honorary Secretary of the French Academy of Sciences


President of IUTAM 1988-1992


Vice-President of IUTAM 1992-1996


Leading scientist in the mechanical sciences




in Paris on 26 February 2009