Hey guys, what do you usually use as your maximum force exerted on your weapons when doing a stress analysis? I always use 1-2 thousand lbs because I figure that's way over kill and if my weapon can stand that, than it should be good at Battlebots. Unfortunately, if you remember from last year, I exceeded those forces in my fight against UTD where I bent my bar.


I hate that my bar bent, but it's amazing that it did exactly what my stress analysis said it would do.

So this year I'm trying to redesign it and maybe learn a better way to analyze it. Like I said, I use 1-2k for the force and I usually get a FOS (Factor of Safety) of about 0.2 which I know is unacceptably low, but I figured it would be alright because the force was extremely high.
I know I'm not using comos properly though. You're supposed to do a motion study and have the bar rotate about the center, but I always keep the center ridged and exert a force on the outer most tip.

I know it's a bit ghetto, but I figure the simplified method only increases the force load gives a general idea of how it's going to deform.

Any ideas on how I should analyze it?

We're trying to get a safety factor of around 4 for critical components in Sum of All Fears (military spec for just about anything involving humans). I'm taking Deformable Bodies right now as well, so an analysis of what would happen if your robot came to a nearly instantaneous dead stop just on paper might be a good approach too.

So no one has any advice on stress testing? Or am I the only one that does it?

I'm not taking our version of computer based deformities until next semester, so right now I'm stuck doing it by hand or guessing my way through Cosmos.

Does anyone have ANY advise on stress testing? I'm not looking for expert advice, but something's better then nothing.

All I can really say is: "safety factor of 0.2 on a weapon = ur doin it wrong."