Ask iMechanica

The timespan for a loading instance is only 0.004 [s]. The load is being driven by a tire traveling at 150 mph which will contact a solid metal surface. I will model the pressure distribution instead of the tire contact. I read somewhere a similar speed metal/metal impact ramp time of 15e-5 [s] would be an acceptable ramp rate. Can anyone cite experimental data for this? 

Even if contact were used, displacement control of the tire would be the best choice and the same issue would arise. Any insights?

Hi everyone, 

I'm trying to develop a crack growth model of two interacting, neighboring, cracks in carbon steel materials. However, I was wondering if I have to take into consideration damage accumilation as I'm doing "CRACK GROWTH RATE" not crack growth. 

any input is highly appreciated, 

thank you, 

Hello,
I'm working on a student project at a university in Germany.
It's my task to create a fluid-structure interaction in Abaqus. I have to implement periodic boundary conditions in Abaqus-CFD.
How can these PBCs be created in Abaqus-CFD?
At the moment, I have no approach and I hope someone can help me!
The values for pressure and velocity have to be equal on the periodic surfaces.
I can select specific values by inlet/outlet but I can't select 'periodic'.
Is it possible to set the input-file surfaces periodic or how do you think I should proceed?

Hello my name is Raghid and I am currently doing my MSc in structural engineering on

transverse stiffeners in steel plate girders. I modelled the plate girder using shell elements

and I fear I might be doing something wrong since the stresses throughout the entire

span of 35m and I am not sure if the end panel which is successfully buckling in shear

is developing its post-buckling strength.

Any tips or suggestions as to why this is happening?

Hello all, I am in a desperate need of some expert help

For a newbie at Abaqus with subroutines,

After months of trying, finally installed Abaqus, verified results all passed.

(Abaqus 6.13, Microsoft Visual Studio 2010, Intel Parallel Studio XE 2013)

 Couple of questions-

1) Error: Problem during compilation: What is wrong with the code below subroutine uhyper? (A former student had this subroutine working, may be in earlier versions but had it working)

Hello 
I do geostatic step for fully saturated soil.

ABAQUS is used.

Hi,

I'm a relatively new ABAQUS user, and have been experiencing some troubles with user subroutines (specifically UMAT's).

At the moment, I am trying to implement a tutorial UMAT available at this site: http://www.eng.ox.ac.uk/NP/ICP/

I'm working with elastic.f and elas_axiforce.inp.  I've modified elas_axiforce.inp to have the lines for DEPVAR.

I'm using a linux operating system, with my .inp, .f, and .env files all in the same working directory.

Dear all,

could someone tell me some equation to get the critical stress for delamination in multilayers?

Thanks,

Dear all,

     I constructed a VUMAT subroutine which including 4 state dependent variables, so I wrote "*Initial Conditions, Type=Solution" in keywords. But, when I run the simulation I get this error:

in keyword *PERMEABILITY, file "Job-vumat2.inp", line 102: The keyword is misplaced. It can be suboption for the following keyword(s)/level(s): material

Analysis Input File Processor exited with an error.

    Could anybody help me? Thanks a million.