rear uprights, FEA trouble, weight and stiffness

[Pauly]

Am just in the middle of doing my FEA for my uprights and was wondering what sort of weight people were getting for their uprights?

Also what kind of loads have been assumed for worst case?

Finally what constraints have people been applying during the FEA analysis?

I have been constraining the pickups(bearing type constraint) and the central bearing cutout but keep getting warning messages(in FEA program 'nx 3.0') about my loads not having an effect as they are located at the constraint points. The result is that my upright is never that stressed. However, if i do take away the pickup (suspension upper & lower + tie rod) constraints and leave the forces the same the results show stresses in excess of 4000mpa and huge displacements in the deformed model.
Any ideas whats going on?

[Pauly]

Am just in the middle of doing my FEA for my uprights and was wondering what sort of weight people were getting for their uprights?

Also what kind of loads have been assumed for worst case?

Finally what constraints have people been applying during the FEA analysis?

I have been constraining the pickups(bearing type constraint) and the central bearing cutout but keep getting warning messages(in FEA program 'nx 3.0') about my loads not having an effect as they are located at the constraint points. The result is that my upright is never that stressed. However, if i do take away the pickup (suspension upper & lower + tie rod) constraints and leave the forces the same the results show stresses in excess of 4000mpa and huge displacements in the deformed model.
Any ideas whats going on?

[Cement Legs]

Pauly, I think the lighter uprigths are comming in around 2 1/2 lbs made from steel plate in a box construction. Our uprigths are about 3 lbs machined from aluminum bar.

As far as loads are concerned we followed the advice of more experienced teams and did our calculations with 1.4, 1.5 and 2.5 Gs for brake, lateral and bump respectively. Our loads were then transfered through to our uprights.

[adrial]

We came in around 1.7, 1.8lbs for the upright body itself with 1/10 degree camber change for the upright/hub assembly.

Similar weight for the hub with integral taylor tripod housing...although that will be getting lighter next year with better geometry.

What sotware are you using for FEA?

Worst case load that we assumed was 1.5G braking/accel, 1.5G cornering, 5G bump. Look at the loaded and unloaded tire.

I dont have any pics handy because I'm not at home. But if I remember I'll post some up later today/tomorow.

[JadgPzIV]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pauly:
the results show stresses in excess of 4000mpa and huge displacements in the deformed model.
</div></BLOCKQUOTE>

Have you enough 'zero' to your Young Modulus??