torsional rigidity

[carmaxxx]

I've noticed that the torsional rigidity of most fsae frames lies between 300 and 1500Nm/deg.

from experience, can you say how much is enough, or at what stage will the increased frame weight counter the rigidity?

also, what is the method adopted to measure torsional rigidity?
a physical test apart, in ansys that is.

is it right to constrain all front suspension mounting points and apply a torque through all the rear mounts?

[carmaxxx]

I've noticed that the torsional rigidity of most fsae frames lies between 300 and 1500Nm/deg.

from experience, can you say how much is enough, or at what stage will the increased frame weight counter the rigidity?

also, what is the method adopted to measure torsional rigidity?
a physical test apart, in ansys that is.

is it right to constrain all front suspension mounting points and apply a torque through all the rear mounts?

[Jersey Tom]

What torsional rigidity is enough is up to you to decide. I'd analyze it as a torsion spring linking two rotational spring/mass/damper systems in something like Simulink, input your front and rear rotational moments of inertia, roll spring rates, and see what happens when you start applying roll moments to one axle or both.