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High Stress Concentrations in FEA Analysis

June 12th, 2011

People who have used SolidWorks Simulation, and indeed other FEA software, will be aware that sharp re-entrant corners will cause high stress concentrations in a final stress plot. Increasing the mesh in this area will only serve to increase the stress intensity. Small fillets are usually applied, or in some cases the mesh is coarsened in this area.

(Reference)

Many models have inside or re-entrant corners which can cause high stress concentrations

High Stress Concentrations are also caused by incorrect boundary conditions (aka loads and restraints).

Example 1 – Tensile Test

The video on the following page compares Hand Calculations to SimulationXpress and SolidWorks Simulation with Reference Geometry restraints, for a tensile test of a steel cylinder.
Simply putting a “Fixed” restraint on a face (which a lot of people just do) is a blind and often an incorrect approach and can cause high stress concentrations. A better method involving using a “Sliding” restraint combined with a Reference Geometry condition can be used to overcome these high stress concentrations.

Putting a "Fixed" restraint on a face may cause high stress concentrations.

 Example 2 – Use a Soft Material

The following article proposes to use a “springy foundation pad” with a low youngs modulus and low poisson’s ratio, attached to the part you want to secure. The springy material will absorb high stress concentrations when a force is applied. Link -> http://www.capinc.com/2011/04/06/imaginary-materials

Use a springy foundation pad part or body attached to the part being loaded

Note: Archived originals

Simulation (FEA) , , ,