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CONTACT in ABAQUS: HARD and SOFT contact techniques

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I am using Abaqus for nonlinear FEA of contact between material1 (soft foam like) and material2 (hard plastic type) in vertebrae for my thesis. I have encountered many problems during this exercise, because I have to include the results of various contact conditions in this situation with friction. I am trying to get results for 

Fatigue crack propagation


I try to do fatigue crack simulation in general FE code (ANSYS) for 3D formulations. I face very hard to get mesh with crack tip elements (for 2D it s quite easy to use KCON options). Any idea how to perform for the 3D crack tip mesh.





Gouse's picture

Probelm with Abaqus/Explicit


I am using cohesive elements to model the interface around a
circular inclusion. First I used Abaqus/standard I got proper results
but when I used same values with an amplitude curve (tabular, linearly
applied) to apply load quasi-statically in Abaqus/Explicit, I could not get a converged
solution. Field variables are oscillating and elements getting
distorted excessively. In Abaqus/Explicit I am applying load very
slowly but even though same problem persists.




I am doing analysis in ANSYS which requires the contact pair to be defined. I am unable to select an appropriate value of Pinball region, Penetration Tolerance and normal penalty stiffness. Does any body have an idea how to select the good values for better solution? If you have anykind of material related to contact pair kindly email me at


Model of three layer Pavement in ANSYS

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Hi everyone,

I am new in IMECHANICA. I am a MS student, doing my research on pavement overlay.

I want to model a three layer pavement in ANSYS and apply moving load. There will beinterface between the layers. How can I apply the load? If I marge and compress after meshing; is this the correct way to do that?

Thanks and regards


GOPALAERO2000's picture

From the Ph.D Student

Hi Every one


 I am a new entrant to this site. This site seems to be very good towards technical aspect.

First of all I would like to introduce myself. I am a Ph.D student working in the area of fatigue.

- Is there anyone to support and share the knowledge in the domain of fatigue?

- Can anyone guide towards the websites that provides very good information about fatigue and related literatures.


Thanks and Regards

Gopalakrishnan Mohanam


Marina Trajkovic's picture


Dear all,

do you know does any entry stored is STATEV, used in UMAT subroutine,
should remain unchanged for the next increment for the case of finite
I know that STRESS and STRAN  will be rotated by ABAQUS but what about the STATEV?

I want to protect STATEV from any rotation by ABAQUS in order to rotate
it in UMAT by my rotation matrix but I am experiencing that it is
different value at the beginning of new increment in comparison the one
as output from previous increment.

Thanks in advance,


Knee Bone IGES file

I am working finite element modeling and analysis of knee bone implants. I am in need of knee bone iges file for analysis. Anybody working in this area kindly send me the iges file

Model of Pavement for moving load


I want to model a pavemnt of three layer and apply moving loads on it by ANSYS. There will be interface between the layers. How can I apply the load? If I merge and compress all after meshing; Is it the correct way to do that?



Optimal structural design against elastic instability

In the classical Euler buckling problem, the critical buckling load can be increased by a factor of four if the first mode is suppressed by placing an additional simple support at the mid-point.

If we solve the more general problem where the additional support is placed at some different point z=a in 0<z<L, the critical load will be found to increase above that for the unspported first mode, but the maximum increase is achieved when the support is at the mid-point and buckling then occurs of course in what would have been the second mode of the unsupported beam.

modelling of axisymmetric cold extrusion die by abaqus

 my problem is simulation of axisymmetric cold extrusion die. the die is conical, i have to determine die pressure, ram force and temprature in billet as well in die, plz see attached file and see simulation figure, my problem is same as in file,i have facing interaction problem in abaqus while solving this problem. plz help me


Hi friends,

I need to transfer stiffness and mass matrices from ABAQUS to Matlab. ABAQUS does generate matrices but those can be re-used by ABAQUS only. Is there a way to use these matrices in matlab. I know about SDT toolbox for matlab and I-MAT but they are costly.


ground water table with no flow

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Dear all


How can I model the static ground water table (no flow) in soil using 3d ABAQUS ?

How to change the Navier equations for non-uniform Lame's constants

Hi Everyone,

                 I have to confess here that I do not have a mechanics background but I am currently working on a problem where i have to solve the Navier equation with non-uniform Lame constants of an object. If anyonme could guide me towards the necessary literature or  any other resource it would be very helpful. Sorry for any inconvenience.

cdeng's picture

A new paper on the nanoscale plasticity in twinned gold nanowires

A new paper titled "Enabling Ultrahigh Plastic Flow and Work Hardening in Twinned Gold Nanowires " from Dr. Sansoz's group just came out on the latest issue of NanoLetters. Attached below is the abstract and the full paper can be found at: We welcome any comment about this paper as well as our research.

Chaboche elasto-viscoplastic model with plastic strain memorization and time-recovery in ANSYS

Hi, I am a reserach fellow of mechanical engineering in Italy. I need to implement the elasto-viscoplastic model of Chaboche in a user subroutine in ANSYS accounting also for the plastic strain memorization and for the static and dynamic recovery. In a next step I sould also need to incorporate the damage variable of this model.

Phase Field Modelling of Fracture Mechanics

Hello To one and All,


I am currently working on my Master's thesis in Computational Mechanics and as the Title suggests, I am working on using phase field theories to model fracture mechanics. The whole idea /concept of phase field modelling in itself has been a very complex topic for me, as it originates in superconductivity theories of which I have but a superficial understanding. I am ok with fracture mechanics terminology as I have worked on it before.


Julien Yvonnet's picture

An XFEM/level-set method to model nanostructures

In the attached paper, we propose a procedure combining an XFEM/level-set technique and Gurtin-Murdoch surface elasticity to model nanostructures with arbitrary geometries. The effects of free surface which are dominant at small scales are easily captured in this framework.

Exact solutions for elastic half-space problems

Hi all

I am looking for exact solutions of deflection & stresses for the following problems:

1.    Elastic half-space loaded by a circular uniformly distributed load
2.    Elastic half-space subjected to a concentrated ring load

I found few journal papers, where reference was given to Timoshenko & Goodier.  But I could not trace the explicit equations for exact solutions of deflection & stresses for the above problems.

Calculation of natural frequency of beam

1. How to Compute the first three natural frequencies of vibration of cantilever beam?

2. How to Compute the first three natural frequencies of vibration of simple support beam?

3. What is Euler column formula?

fethi ABBASSI's picture

Composite thermoforming-ABAQUS

I need to modeling  an example of thermoforming of composite (woven PPS/ Carbone) on ABAQUS, which can help me (if possible to give me a tutorial)
thank you

Difference in vibrational characteristic of CNT in Thermal Environment

Can anybody suggets, (especially working in experimental field on CNTs ) whether there is any change in vibrational characteristics in CNTs subjected to temperature change.(especially in fundamnetal frequency values)


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