Engineering software tool for analyzing widely varying loads on a structure

[geesaman.d]

Hello,

I have an engineering problem that involves the stress of a shaft system with multiple load points and the loads have varying direction and magnitude. The variation over time is *not* cyclic - it is random. If you ignore the variations for a moment, this is an easy linear structural FEA.

The problem is a Miner's rule fatigue calculation but because there aren't fundamental frequencies, it is very subjective and manual to sort out the variations that stack up very quickly.

Can anyone advise of a software tool that can manage the Miner's rule fatigue calculations and varying load cases? Bonus points if it will set up and run the numerous FEA load cases.

Thanks,

David

 

[geesaman.d]

I might have my own answer: break up the load vs time history using ASTM E1049 methods and apply a tool like Fatigue+ to process the load cycles.

If I choose the right cycle counting algorithm I could limit my FEA runs to a handful.

The trick (as always) is to settle on material properties for ultra-high-cycle (gigacycle++) fatigue to suit our case.

 

[rb1957]

ncode may help ?

sounds like ...
run an FEA with all the various loads
create a stress history at each surface node
convert these to rainflow, then cumulative damage

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[dmapguru]

Take a look at CAEFatigue by Hexagon. It allows variability to be introduced into the problem.