Ask iMechanica

Hi all,

I do know that we can get 1-st PK stress P from taking derivative of the strain energy function W with respect to deformation gradient F. However, would there be any way to back the W out from integrating P with F, or something similar?

Thanks in advance,

Shawn

Hello,

I have modelled a geostatic step in an undrained clay in ABAQUS. This step finishes very quickly and correctly. But the geostatic step is not converging when I have a circular steel plate inside the soil mass (tangential behaviour is through coulomb friction and normal behaviour is hard). Does any body know the reason behind this divergence? 

Regards,

Cyrus

Hi everyone,
I want to build a sequentially coupled analysis of crack growth due to hydrogen diffusion under stress.
It includes two models which have different element types but share the same nodes.
First, the elasto-plastic stress and strain are calculated around a crack tip in one model, the material follows Ramberg-Osgood plasticity model;
then the stress of the previous model is used in a mass diffusion model, once the crack  tip concentration has passed a criterion, the crack grows and a new crack length is set in the stress model and the cycle is repeated.

Hi,

i have a problem with the periodic boundary conditions. I want to implement the boundary condition for example

which i found it in the internet. The first equotion is u_facebuttom - u_facetop=0

So i know that we can do this with creating Constraint and selecting Equotion.

At first i define Sets FaceButtom and FaceTop which includes all nodes on bottom and top. Here is a picture for the Set Face Top

Anyone help me,please. I am new user of Abaqus on Ubuntu ( I have to run UMAT on Abaqus, if I use window platform I could not find the compatible compilers ). When I finished to set up Abaqus ver6.10 on my Ubuntu, and edit the .bashrc file like this:

#abaqus
alias abaqus=/home/mrha/SIMULA/abaqus/6.10-1/exec/abq6101.exe
export LM_LICENSE_FILE=27011@MrHa
alias abacae=/home/mrha/SIMULA/abaqus/6.10-1/exec/abq6101.exe\ cae\ -mesa
alias abalic=/home/mrha/SIMULA/License/lmgrd\ -c\ /home/mrha/SIMULA/License/abq6101.dat\ -l\ +/home/mrha/SIMULA/License/licserver_debug.log

Hello,

I have noticed that if an abaqus analysis is run through abaqus.cae/submit, the analysis might be stopped for a couple of hours to check the licence, end up increases the analysis time. Could you please advise whether this problem could be overcome if I run the analysis through command prompt?

Cheers,

Cyrus

Dear everyone,

  I am new to Abaqus and I have been struggling for the past 3 months about this issues I am facing on my modelling...

hello,

I am trying to extract mass and stifness matrices of a simple beam using abaqus. The stiffness matrix works fine but when i requested the mass matrix to be exctraced the section in the ASCII related to mass matrix is empty. here my script:

*HEADING

Fixed Beam

ELEMENT: B21

*NODE

1, 0., 0.

11, 1000., 0.

*NGEN,NSET=allnodes

1,11

*ELEMENT,TYPE=B21

1,1,2

*ELGEN,ELSET=elset

1,10

*BEAM SECTION,SECTION=RECT,ELSET=elset,MATERIAL=Concrete

200., 300.,

Hello everyone,

I made simple cantilever model in Abaqus/Explicit. For concrete I have used Concrete damaged plasticity model and for reinforcement I have tried two models (one with Truss and second with Beam elements). I have assigned displacement as BC (Smooth amplitude) in Reference Point at the end of the beam, and I have coupled RP with the end of the beam. For concrete beam I have used C3D8R elements.

For history output I have requested Reaction force in RP and energies for whole model.

But results I am getting aren't expected.