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Usermat: Linear viscoelastic model with geometric nonlinearity

Submitted by augustus on
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ansys; viscoelasticity;

Hello,

I have implemented a linear viscoelastic model using the user subroutine Usermat in Ansys.
I have used the classical paper: "Formulation and implementation of three-dimensional viscoelasticity at small and finite strains" of Kaliske & Rothert (Simo's approach) and it works fine for small deformations.

It is written in the documentation that in the case of a simulation with large strain (geometric nonlinearity), one must rotate the state variables.

Linking Fortran with LS-DYNA

Submitted by fff10000 on
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Hello everyone:

As I was combining my ls-dyna K file with Fortran code (user_defined_mat and user_defined_shell....), when I compile using Intel Parallel Studio, it always shows the error: fatal error LNK1181: cannot open input file 'libguide.lib'.

Anyone knows how to solve this problem? I am using WIN7 64bit, LS-DYNA 64bit, Intel Parallel Studio XE 2015. Really got messed up, thank you very much~

Best regrads 

Localized compliance with Castigliano's theorem

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fracture mechanics

I'm attempting to compile a local compliance matrix using Castigliano's theorem as described here. I'm having trouble with it and attempted to do a simple example by hand and picked the double cantilever beam specimen and analyzed it with Euler-Bernoulli beam theory (attached). Despite my best efforts, I can't reproduce the correct answer using the theorem as is but only if I modify the limits of integration.

Error messages when I import an Abaqus example file in Abaqus CAE

Submitted by Flik on
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Hi, 

I have problems with running a file in Abaqus, it gives me this error message:

 

WARNING: The following keywords/parameters are not yet supported by the input file reader:

------------------------------------------------------------------

*ELPRINT

*FILEFORMAT

*NODEPRINT

*NSET,UNSORTED

*SYMMETRICMODELGENERATION

*SYMMETRICRESULTSTRANSFER

The model "tiretransfer_symmetric" has been imported from an input file.

Please scroll up to check for error and warning messages.

Modelling cyclic behaviour of soil using UMAT

Submitted by Prashanthi on
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Geotechnical engineering
cam clay
ABAQUS
UMAT
finite element modelling

I have been trying to model the cyclic behaviour of soil. I got a UMAT. But when I'm using UMAT, it is creating lot many errors (like numerical singularity and excessive distortion). I have constrained it properly. I tried running my model with an inbuilt material (clay plasticity) and I'm getting results. Here I'm not even able to move from the initial geostatic step. Can anyone please help

using absorbing layer to reduce the model size

Submitted by Manal Hussin on
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Hi all,

Im using ABAQUS to simulate the ultrasonic wave propegation in the Prestressed concrete beam, however indorder to get a results I have to use very small mesh around 1mm and it is iompossible to run the simulation with this small mesh .just wondering if any can help me to reduce the model size such as using the basorbing layer or  any other technique can reduce the model size without affecting the results?

your help is really appreciated

manal 

Poster Abstracts - accepted until Feb 19th for Nanobrücken 2016

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conference

 Nanobrücken 2016: A Nanomechanical Testing Workshop & Hysitron User Meeting will take place March 2nd - 4th, 2016 at the INM - Leibniz Institute for New Materials in Saarbrücken, Germany. This will be the 6th edition of the now-annual Nanobrücken workshop series. 

As in the past, the workshop is open to all aspects of nanomechanical and nanotribological testing, including biomechanical, in-situ experimentation and theory/simulation.

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