MES impact test problems

[Anonymous]

Hi All,

I am getting a bit desperate and I'm hoping to get some guidance to find out what I'm doing wrong.

I am trying to replicate an impact test on a product that I am currently developing but I am only an inventor user and the FEA only works in the elastic limits for stress etc and does not give results for deformation. I have been advised that sim multiphysics is the way to go but I would like to see the results before committing to paying for the program so I am only using a student version at the moment.

I have imported my assembly from inventor without issue. Meshing both surface and solid have all been fine but this is where my knowledge and experience runs out. I know I need an MES simulation with nonlinear stress and the parts of the assembly a want to check for deformation have been set to Von Mises with isotropic hardening and the rest are elastic isotropic.

The contacts I have left as bonded other than the contact between the ball and the top surface, this I have changed to surface to surface high speed impact.

I have fixed the assembly on the surface that it would be mounted and used a nodal force of 1800N on the top of the ball (through the axis) and set the load curve of 0.02s to a simple 3 point multiplier (0,0) – (0.01,1) – (0.02,0) to try to keep things simple. I have also quartered the assembly to simplify the analysis but I have added symmetry constraints (turned off on image below).

There seem to be no errors on the log yet I am not getting any results and cannot find any further info online.

As I do not currently have any IP on this product I am reluctant to post it on the online database but I could email it direct if required.

Any help would be greatly appreciated.

Thanks and regards,

[ilyas_drawbridge]

Hi,

What about the analysis log, what does it say? The analysis log would be the best way to look at whats happening during the analysis, especially MES. My guess here is that your time step size is too large. Try with a smaller time step. This is done in the Analysis Parameters dialog.

Regards

Ilyas

[Anonymous]

Hi Llyas,

The log does say that the analysis timed out (autotm). The total time of analysis is 0.02s which I originally set to 50 time steps. I will try 100 steps and see if I can get any further than step 8.

Thanks for your help.

Regards,

Chris

[zhuangs]

Hi Chris,

Could you attach your log file (ds.alg)?  We will have a look.

-Shoubing

[Anonymous]

Hi Shoubing,

I have attached the log for you. The attached is for a 50 time step analysis which failed at the first time step. I also had the same issue with 100 time steps however when I tried 20 time steps it failed at time step 8.

Regards,

Chris

[zhuangs]

Hi Chris,

In the log file, there is a warning messages:

 ** Warning: for the models having (general) contact element,
             general surface contact, or impact planes,
            <MES with Nonlinear Material Models> is recommended;
            <Large deformation> is also recommended for all parts.

Please change the analysis type to <MES with Nonlinear Material Models>, if it is not.  And for all the parts, <Large deformation> should be used.

Please check whether this can help.

-Shoubing

[Anonymous]

Hi Shoubing,

I think this warning is just a general warning as the analysis type is MES with non linear models and all are set to large deformation.

Regards,

Chris

[zhuangs]

That warning is output to log file only one or more conditions are not satified.

-Shoubing