modified Riks method (collapse)

[dkeatley]

I cannot seem to get my models to collapse in the viewer. The modified Riks method seems to stop short of global buckling (or even partially buckling). Any suggestions?

 

[truckcab]

What kind of structure is it that you evaluate?

 

[dkeatley]

It is a 30" diameter plastic pipe.

 

[bassmanjax]

How is the load applied - is it axial, bending, torsion..?

Have you used a *IMPERFECTION to seed the buckling mode?

Regards

Martin Stokes CEng MIMechE

 

[dkeatley]

The pipe is surrounded by soil and the load is a pressure load applied from above. Yeah I use a buckle step to seed the buckling mode. I seem to get the error "too many attempts made for this increment."

 

[mrgoldthorpe]

Try
*CONTROLS, ANALYSIS=DISCONTINUOUS
in that step.

 

[dkeatley]

Thank you for the suggetion to run a discontinous solution, but it did not even result in an extra increment. Any other suggestions?