SOLIDWORKS Simulation Fatigue Analysis

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SOLIDWORKS Simulation Fatigue Analysis

The process of progressive structural damage in a component subjected to alternating loading conditions that may lead to failure after a sufficient number of cycles accurately describes fatigue.  If you design products that need only to last for a single use, the rest of what you will read beyond this does not apply to you.  For those of us designing products that must last for multiple use cycles, even cycles into the tens of millions, fatigue life is an important design consideration.  If you are still not convinced that fatigue life is important, maybe it would change your mind if you knew that fatigue failure is the most common form of mechanical product failure.  Also, just because you design products to a safety factor does not automatically mean that your product will be immune to fatigue failure.  Fatigue life of products is such an important part of product design that the ability to estimate fatigue life is included in all three versions of SOLIDWORKS Simulation – Standard, Professional, and Premium.

Conducting fatigue analysis in SOLIDWORKS Simulation starts with your structural analysis study results.  Set up and solve at least one linear static analysis to generate the stress data used for calculating fatigue life.  Alternately, you could also solve a linear dynamic study, either modal time history, harmonic, or random vibration, and use those structural results to solve for fatigue life.  Once the structural results are available, setting up a fatigue study in SOLIDWORKS Simulation is straightforward.  The structural analysis is an “event” that consists of the total number of cycles that the product will experience and the loading type.  The loading type describes how the load is applied to the product, most often as a zero-based or fully reversed load.

The material definition needs to include data for an S-N curve, or stress to number of cycles.

Finally, there are a few study properties to set, such as specifying how to calculate alternating stresses and which mean stress correction method to utilize.

When the fatigue study setup is complete, just solve the analysis to generate the results.  There are several fatigue plots available with the most common being a damage plot and a life plot.  A damage plot indicates the percentage of product life that has been consumed by the applied event(s).  The life plot shows the number of cycles of the event(s) that would cause fatigue failure at every location on the product.  And with your fatigue analysis complete, you will have a much higher confidence in your design knowing that it will last for as long as you intend it to.  Now go make your products better with SOLIDWORKS Simulation!

Bill Reuss

Product Specialist, Simulation

Computer Aided Technology