Loading and unloading of a beam

[klheureux]

I need to create a hysteresis curve on a beam through load and unload. So I need to capture a force\deflection curve while loading and unloading. This is also on an assebly so I need to do contact analysis as well.


Is this even possible in Mechanica?


Kevin

 

[esundman]

KL,
Contact analysis in Mechanica is possible, although it can increase the run time by a factor of 5 or 10. I always set up my contact surfaces manually; the auto-detect feature includes all surfaces, most of which will never contact. Contact surfaces must be close (within 5 degrees?) to parallel, and the deflections must be small. You'll never be able to model something like a rubber cv-joint cover in Mechanica.

Force & deflection curves are easy if you set up a measure of deflection at the point you are interested in. If you use more than one load case in your analysis, you can do one run and change the load multiplier in the results. Search 'measure' in Pro/M's help section.

Hysteresis is due to non-linear effects. Hooke's law about force equaling stiffness times deflection (F = k*x) is only valid in the linear region. In a static analysis Mechanica doesn't account for how fast the load is applied, or how long it is applied (creep).

 

[klheureux]

What I am looking to do is capture energy return/disapation in a composite spring.

 

[esundman]

Hmmm... Mechanica will tell you the total strain energy, but that is perfectly elastic. There is no dissipation involved.

I think Mechanism (yet another $$$ add-on) can model springs or collisions with coefficients of elasticity, but I am not sure how it all works.