Harmonic analysis using nonlinear springs

[objengrs]

When using COMBIN39s, what does a harmonic analysis do to solve? Linearize them using whatever slope it finds at zero load? Same with other nonlinears?

 

[meshparts]

That's correct! It linearize the slope at zero load.

Regards,
Alex

 

[objengrs]

Thanks.

I have a structure being driven into hardening supports due to thermal expansion or contraction. Test work shows that this changes its dynamic response. I'm modeling using PSTRES effects found using a static run at elevated temps, then a harmonic run (using the actual external operatinal cyclic forcing function) as follow-up. Unfortunately, the harmonic run still applies the previous temperature as an alternating load--which then unnaturally augments the dynamics.

Any suggestions?

 

[cbrn]

Hi,
unfortunately there are two "bugs" in the harmonic response analysis:
1- it is still in linear domain
2- any load is applied as a sine function, isochronically (though you can shift phases between one another).
At this point, I see no other solution (sigh...) than to run a full transient analysis. By the way, you won't need the static run any more, but every substep will take the same time to solve as the static run, so be careful if your model is huge...

Regards