Stress Singularity's? 1

[Paul1235]

Hi All,

I'm a product designer at the moment and I am trying to teach myself statics & mechanics alongside FEA to try and move up the ladder. Unfortunately, I have no one experienced enough to turn to for advice on such problems. I am just analysing a loaded bracket (this is a not a production model):

The idea is that the bracket is fillet welded to the adjoining plate around its perimeter. A load has been applied to the pin along the Z axis.

Now, where my knowledge is lacking is in being able to determining whether or not the stresses are singularity's or is the bracket tearing away from the sheet? Would adding fillets around the perimeter give me more realistic results?

Additionally, I did perform a convergence study and the stresses do not converge the just keeping going up and well over realistic material yielding.

What would you guys do in this situation?

 

[FEA way]

When the stresses keep increasing with mesh refinement like in this case then you've run into a stress singulrity. Try performing nonlinear analysis (with plasticity included) and see how the stresses behave.

 

[rb1957]

some of thee look like impossibly sharp shear loads. The shaft going through the lug hole sees this … an instantaneous increase in stiffness at the edge of the lug. Material non-linearity will help.

another day in paradise, or is paradise one day closer ?

 

[Paul1235]

Thanks guys!

When you say with plasticity included, am I correct in assuming that I need to apply a plasticity Von Mises material to the model in the non-linear study?

 

[FEA way]

Yes, that’s the basic plasticity model in SolidWorks Simulation and you can use it to increase the accuracy of results.