Fatigue - Number of cycles to failure

Manekshaw_22374

Hi,

I am performing a stress analysis for plastic parts, specifically for snap fits.

Since snap fits, are bound to be open and close, I want to do a hand calculation to find the number of cycles for failure, based on the stress analysis I performed using Optistruct.

Can you please let me know how to calculate the number of cycles for failure.

 

Since the part I am analyzing is plastic, it does not have an SN curve.

 

Please let me know how to address this problem.

 

Regards,

Manekshaw

 

Joshua Pennington

Hello Manekshaw,

You mentioned using OptiStruct, but are you also aware of our focused fatigue solution called "HyperLife" ? HyperLife contains workflows tailored to fatigue analysis and contains some general recommendations for material SN and EN curves. You may also input your own. HL documentation has tutorials and theoretical background/ reference for fatigue theory and application.

To use HL you simply need to perform your structural analysis (eg linear statics) and then import those results into HyperLife. HL will then allow you to setup your model for fatigue analysis. HL also has great tutorials.

If you still would prefer OptiStruct, would you please first begin by referencing our HyperMesh tutorials. You'll find fatigue analysis category, and there is a selection of them. I would recommend first OS-T 6020 which is the S-N approach.

Regards

JP