Do I have to select failure criterion for accurate results?

[bendd]

I came across an error in my material library which left the material on my model to say "Unknown" instead of "Mohr-Coulomb". I ran the model without realizing it to find that it ran in about 10 minutes, instead of the hour and a half it was taking before. I have not quite familiarized myself with everything in Simulation as it is new to me, so I don't know what difference this made in calculations. Does Solidworks calculate stress differently? Do I need a failure criterion to be selected?

I already know that my model will not fail. I'm simply trying to estimate a deflection when a load is applied.

 

[GregLocock]

In Abaqus the solve time for MC is different than for a linear elastic material, so I'm guessing yes your result is not unusual, and no you don't need a failure criterion if you aren't interested in failure.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[drbooshkit]

The failure criteria does not factor into the stress calculations. It's only used when defining the Factor of Safety plot.

There are, of course, different ways to define failure. Simulation uses four. By default, von Mises (distortion energy) criteria is used since it correlates best with imperical data on ductile materials. Tresca is slghtly more conservative (depends on loading).

Mohr-Column shouldbe used for brittle materials.