Hello everyone,

 I am implementing a uel user subroutine in ABAQUS. This uel is for modeling contact in X-FEM framework. Thus, it's a nonlinear problem and I need to store some solution dependent variables during each iteration. I know I can store SDVs in SVARS. But this vector will update at the end of each step, and not during iterations. Anybody knows about this problem?

 I really appreciate if anybody can help me with this.

    Thanks

    Ehsan 

Hello there!

 I am fairly new to ABAQUS but I have been trying to model several experimental set-ups on cold-formed steel beams. I intend to obtain both the elastic buckling critical modes (*buckle analysis), as well as the load parameter corresponding to failure, which i first modelled through a NLGEOM analysis (*STEP, NLGEOM, INC=xxx/*STATIC, RIKS).

 I have realized that using ABAQUS/Standard and applying distributed loads, often leads to poor results. Thus, I have decided to move to a quasi-static model (ABAQUS/explicit) where displacement is applied instead of force, through the *boundary , amplitude command. In this context,I have found some trouble answering the following doubts:

Hi all,

I have a problem with periodic boundary conditions using contact elements with a cohesive zone law in Ansys.

In my micromechanical simulations of an RVE with periodic boundary conditions I would like to have a predefined fracture path. My aim is to realize the fracture path with voronoi cells. There I get problems at the boundary of the periodic domain.

A picture of the simplified problem is attached here:

http://dl.dropbox.com/u/4920002/PBC_CZM.png

The domain here is periodic and square. The red lines symbolize the cohesive zone law which connects the coincident nodes.  I have no problem with the red nodes.

hi all,

I have some problems with contact elements in ANSYS.

My model is a cube of matrx containing two fibres with periodic boundary conditions. The interface between Matrix and Fibre is modeled with contact elements and cohesive zone law. 

In 2-D everything works out just fine when bringing up displacement in x-direction. Here is a movie I made of the Contact Status over the loadsteps:

http://dl.dropbox.com/u/4920002/2D_contactmovie_ContaStat_0.4.avi

Doing the same in 3D brings up some problems. The Contact status is not behaving as expected.

Hi there,

I'm using SPH in LS-DYNA as my tool to simulate the projectile penetrate the box. Both projectile and box are modeled as sph. 

I'm having problem to determine the suitable contact of these two entity.

Could someone please help me... any tips that will help me to tackle this problem is highly appreciated!

Thanks... 

Dear all,
In my FE model (pin on disc), I would like to define a contact property between pin and disc with a friction defination available in ABAQUS. I have assumed that friction coefficient depends on parameters like slip rate, pressure and temperature only. When i used friction coefficients with slip rate and pressure, model works without any error but if i use friction coefficients with slip rate, pressure and temperature, the model doesn't work and come up with following errors;

"Error in job Job-1: Internal error in look-up table generation.  Check that dataline entries are sufficient to describe the dependence in all independent variables"

Can anyone please help me to get rid of error?

Dear All,

I am running an axisymmetric model of a parabola tip on rigid surface contact under external load controlled by CLOAD. However, the CPRESS value outputed integraded over the annular areadoesnot equal to theexternal load inputed. The reaction force from the system does though.

I am suspecting that there is shaer component in the numbers given by CPRESS, but CSHEAR are all zero. Could anyone give me a hint on this problem.

Thanks a lot,

Jingjing

Hello, I am modeling the spherical indentation of a poroelastic layer. I am modeling the indenter as a rigid analytical surface. As you know, the total pressure in a porous medium at each point is the sum of the elastic stresses from the matrix, and the pore pressure caused by fluid pressurization. Abaqus provides both the pore pressure and of course the rest of the stress quantities.

Treating volumetric inequality constraint in a continuum media with a coupled X-FEM/Level-Set strategy

N. Bonfils, N. Chevaugeon, N. Moës

(accepted for publication in computer Methods in applied mechanics and engineering).

Hello all,

This is my first post here. This seems be an informative and helpful forum.

I am trying to model the rotation of a "hard" shaft as a result of motion of 2 strips of soft materials (please see attached figure).

The strips are deformed due to external forces and as a result, contact pressures are applied on the shaft. The forces are then varied on the strips leading to net rotational forces on the shaft.

I am interested in the torque applied on the surface of the shaft and the angle of rotation (from some abituary changes in forces). I am not interested in the kinematics of the problem.

I have set up the model as follow in ABAQUS/Standard:

Dear all,

I'm using LS-Dyna and I would like to model the interaction between a viscous fluid  and metallic substrates.

If everything is working in 3D, it's not the same with the 2D...

Indeed I've used each contact algorithm (I think) in LS-Dyna and each time the contact between my 2D elements and the sph is not initiated.

Does anyone has an explanation to this curious problem ?

Maybe I'm not using the good contact setting.

Or contact between sph and 2D elements is not available in LS-Dyna.

Can you help me ? 

Thanks in advance

 Best regards

 David 

I'm simulating the interface between a steel plate and the fire proof coatings covering the steel plate. The elements i use in the simulation is contact 173 with a material property of debonding,which is defined as cohesive zone model.(CZM)

 CZM in ansys provides  TBDATA such as maximum contact stress,contact at the completion of debonding, but what's the problem is that I failed to set the initial contact stiffness. it's true that ansys provides FKN to define the contact stiffness, but it's just a stiffness factor.

Dear all,

           I did a 3 pt bending impact simulation with an elasto plastic model. But the slope of contact force vs time curve is too steep at the beginning of the impact. One trivial way of reducing the slope is by reducing the young's modulus of elements in the vicinity of contact or the impactor. Also reducing the mass of the impactor and the impact velocity did not help in reducing the slope.

Is there any other non-trivial parameters that controls the slope of contact force vs time plot? Thanks ina dvance.

Hi,

Initially, I asked this question to the Yahoo Group COMSOL
(FE package for multi physics simulation) because I thought, that there I
can find someone who is familiar with both COMSOL and Abaqus.
Unfortunately, among the experts of COMSOL I did not find an expert in
Abaqus.

i am new to Abaqus and i am unsing Abaqus 6.10

i planned to solve a contact problem by taking a bearing for example problem. i modelled the bearing section in pro-e and inmported it to Abaqus.

*i gave the material properties of steel for both ball and races

* in interferance i defined ball as master and the surfaces in the reces in the bearing as slave. frictionless.

* i gave pressure on the top race and arresteed the bottom race.

* the sides were given symentric with respect to y axis.

when solved i get the job is aborted.

the error i get is

=>displacement increment is too large.

=>the increment value is too low

1. We present an interesting application of ADINA FSI in the study of carpal tunnel syndrome. The analyses involve large deformations and contact of multiple flexible bodies which are immersed in a fluid:

http://www.adina.com/newsgH71.shtml

2. Please recall that we offer a very attractive academic package, for research and teaching, for university users. For more information see

http://www.adina.com/educ.shtml

This studentship has now been filled, but there may be further similar studentships to follow.

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

I am fairly new to ANSYS and have been trying to model the interaction between glass micro-spheres and silicone polymer micro-structures for my dissertation research.  I've been working through the online manual, but have been getting very odd results when running the simulation.  Any help at all would be appreciated.  The summary of my problem is as follows:

 Modelling:

It may help to first refernce the first two images at : http://bdml.stanford.edu/twiki/bin/view/Main/AnsysModelling

We present an application of ADINA in the thermo-mechanical analysis of friction welding. Please see: 

http://www.adina.com/newsgH61.shtml

You can find many other examples of applications of ADINA in the analysis of multiphysics problems here:   

http://www.adina.com/multiphysics.shtml

Hello everybody,

I'm trying to add friction in my model.Now I have a body that is simply supported in a direction (vertical) and free to move in another one (horizontal). I want to use Coulomb friction in the horizontal direction in order to reduce displacements in that direction.

I read Abaqus User's Manual vol5 30.1.5 (frictional behavior) and I followed commands written there, but I think that works only with multiple bodies and not with a single body. I'm using Abaqus 6.7-1.

Could Someone help me?

Many many many thanks

Nicholas

Hi.

I have an issue related to recent change in ABAQUS new version.

 I've recently found a problem related to cotact data in ABAQUS new version, 6.8. I use fil files, but I've heard from a Simulia engineer that data file also has the same problem (I have not checked it out yet.)

Tuesday, June 9 – 4:00 PM, EDT

Thursday, June 11 – 9:00 AM EDT

We welcome applications for a 4 year PhD positon in the field of computational mechanics and materials science. Further details in the attachment.

I recently encountered the research of Phil Attard and others, in which the contact problem is solved, relaxing the restrictions of the traditional contact models (Hertz, JKR, DMT) and solving based on a formulation where the governing equations are derived using finite-range surface forces and calculated numerically, self-consistently.

I have enjoyed learning about such models and believe they may have practical application in nanomechanics. However, I find my breadth of my knowledge challenged when it comes to understanding the model's derivation.

A post-doc position on multiscale simulation of cell contact and adhesion shall be available this coming Fall at UC Berkeley. We are seeking for a person who has experience and background on finite element computations, especially in cell contact/adhesion modeling and simulation or finite deformation simulations.

Anyone who is interested in the position please send an email, resume, and reference to li@ce.berkeley.edu