File: PVE-4048, Last Updated: Feb. 24, 2010, LB

Surface models can be challenging to mesh. Parts that touch might not share nodes preventing the correct transfer of loads. The resulting calculated stresses and displacements can be wrong.

A segment of the bottom half of storage sphere - here 1/2 of 1 leg is being analyzed.

A segment of the bottom half of storage sphere – here 1/2 of 1 leg is being analyzed.

The sphere and legs are shell modeled.

The sphere and legs are shell modeled.

The stresses in this leg are wrong:

Calculated stress values

Calculated stress values

Close up of the leg to skirt attachment

Close up of the leg to skirt attachment

The stress distribution in the leg to skirt attachment is uneven. Turning on the mesh shows the uneven mesh that is supposed to be connecting these two parts.

The mesh is not joining along the edge

The mesh is not joining along the edge

The problem does not go away with mesh refinement or tolerance adjustments. The problem is intermittent – some parts will join, some not. A recent update to SolidWorks Simulation can fix this problem:

Standard mesh fails

Standard mesh fails

Curvature based meshing works

Curvature based meshing works

That's better!

That’s better!

Curvature based meshing was not include in SolidWorks Simulation 2008. This example was run in SolidWorks Simulation 2010.

Update: An alternate fix is to knit the surface.

Update: An alternate fix is to knit the surface.

Here the standard mesher was used with the leg surface knit to the skirt. The standard mesher produces a better looking mesh.