constraint for torsion rigidity analysis of chassis

[ashu_win]

I am doing analysis of chassis using Ansys 10.0. Using the beam element 189, how to constrain the chassis for the calculation of torsion rigidity. Applying constraints at all the suspension points is giving a problem. The solution tells the model is improperly constrained as displacement at one of the nodes is greater than the limit. Also, How to apply constraints, at nodes or at lines or at areas?

I am new to ansys and this is our first attempt at fsae car. Please do help.

[Brett Neale]

Model your wishbones, pushrods and uprights too, then constrain the chassis at the hubs on one end and apply torsional loads through the hubs on the other end. If you're after chassis-only stiffness, model the suspension as rigid components with no flex. Your analysis should be simple enough to simply apply loads at nodes, however if your design has loads coming in off of nodes then it would be better to model them as they will exist in real life (significant loading into non-nodes is generally bad anyways...).

[the weldmeister]

there are several constraints and load conditions which can be used to calculate torsional rigidity. do a proper search on the forums, and you'll find them all.

you could also tell me your email address, and i'll mail you some of the methods that we used.

sujaykawale@gmail.com

[vandit]

@ ashu

first of all which team you belong to ?

this is how we conducted our chassis analysis in 10.0....made the chassis as lines with nodes and gave the different properties to lines according to pipe diameter and wall thickness...also we modeled upright and push rod with a-arms...we kept a rigid bar instead of damper and spring system....then we constrained the three upright and applied load on 4th one.....it gave us results which we were not able to tally with physical testing of chassis....

i dont know how far above method is appropriate but i found this method on this forum only...