quasi static analysis with mass scaling

[mollam80]

hi

I have a problem with abaqus explicit if you can help me it is really appreciated.

I am trying to model compression of a hyperelastic cylinder. My model is axisymmetric with two rigid plates and a deformable body in the middle. Upper rigid plates moves with 2.5mm/sec and duration is 120 seconds. I used standard but when I am allowing finite sliding with friction it is really consuming CPU time alot and giving the error about the specified increment is exceeded so I switched to explicit analysis. Now I have problems with mass scaling. In order to increase computation time and take out inertia effects I am using mass scaling but this time I am getting ratio of deformation speed to wave speed error. Can anybody help me about this problem? What level of mass scaling should I use? and by the way What is the time scaling? is it something stretching the analysis time to real time: let say I have time period for step 10 and set time scale to 12 then real total time would be 120 sec? How time scale and mass scale can work together?

thanks in advance.

 

[rstupplebeen]

First can you post both of your models? I would greatly consider going back to standard if you are trying to model a quasi-static problem.

Mass scaling artificially increases the mass of the model so that larger time steps can be used. In effect it is making inertial effects larger not smaller.

I hope this helps.


Rob Stupplebeen

 

[amubashar]

Section 13 on Quasi-static analysis with Abaqus explicit in Getting Started with Abaqus Manual should provide answers to your questions.