simple composite plate. 'too many attempts made for this increment'

[lukemckaysmith]

Hi I am modelling a 16ply (45/0/-45/90)2s laminate in Abaqus and am having real trouble getting to a solution under very simple loading conditions. I have simply fixed a flat plate of the laminate at one edge and then attempted to apply a force at the other end.

Under no loading conditions have I been able to converge to a solution. (pressure load, distributed load, point load)- I have tried to lower the load to very small so that the plate would not be undergoing large distortions..

I get the error..

'Too many attempts made for this increment'

whereby in my message log, the solver has tried for smaller and smaller increments from 1 to 1x10-5; and none of them converge.

My mesh is very fine.

I have experience with Ansys but never Abaqus so I am quite new to this software. I think I am doing something fundamentally wrong to be consistently getting this error message. Any suggestions for rectifying this problem I would be v grateful!

Luke

 

[rstupplebeen]

Do you have the plate's edge constrained in all 6 DOFs? What type of elements are you using? Try fixing all edges and applying the pressure load and see if it solves. I hope this helps.

Rob Stupplebeen

https://sites.google.com/site/robertkstupplebeen/

 

[lukemckaysmith]

Thanks for your reply Rob. I had modelled a quarter of the plate and applied X-symmetry and Y-symmetry boundary conditions. I am using continuum shells with SC8R elements.

I have since realised my problem... I applied my X-symmetry where my Y-symmetry should have been and my Y-symmetry where my X-symmetry should have been! An embarrassingly simple mistake.

I am now moving onto modelling progressive failure; my plate is in tension now with a hole in it and I am trying to make it so failed elements are deleted and then the load reapplied.

Thanks

Luke