Contact problem

[markeaton]

Hi, I’m fairly new to abaqus so hope I’m not being to stupid.

I’m trying to produce a crude model of delamination in a square composite plate subject to an in-plane buckling load. The model consists of a square plate with a circular hole in the centre. Two thinner circular plates are offset to fill the hole and joined to each other and to the square plate around there circumference only. All are constructed from S8R5 shell elements.

I’m using the following contact set up to stop the two circular plates passing through each other.


*SURFACE, NAME=thin, TYPE=NODE
thin, 1.0
**
**
*SURFACE, NAME=thick, TYPE=ELEMENT
thick_delam, SPOS
**
**
*CONTACT PAIR, INTERACTION=CONTACT, small sliding, adjust=0
thin, thick
**
*SURFACE INTERACTION, NAME=CONTACT


I’m running the model as a non-linear riks analysis using the following step


*STEP, NLGEOM, INC=300
*STATIC, RIKS
0.05, 1, , 0.1, , 4725, 2, -5


The problem I’m having is the contact will not converge so the model keeps falling over before it gets anywhere.

Does anybody have any suggestions.

Thanks,
Mark.