Hello. Please consider that:barrti wrote: ↑Mon Apr 05, 2021 1:14 pm Hi Jose,
I'm working through the Tennis Racket model where we shift the relative centre of mass after shifting the structural node from 0,0,-374 mm to 0,0,0.
Pressing Recalculate didn't work.
I shifted the structural node but could not change the relative centre of mass?
Any ideas?
*In both cases, stable and un-stable rotation, the node is at the center of mass of the racket. In these examples you do not have to move the node, so the relative center of mass in both examples is (0,0,0).
*if you move any node, the software will automatically re-caluclate the relative center of mass, you do not have to recompute the model. But for these examples you have to leave the nodes at the center of mass of their rigid bodies.
*What causes the unstable rotation is the momments of inertia of the tennis racket (intermediate axis theorem), not the position of the node relative to the center of mass. Have a look at the initial conditions (the initial angular velocity) of the nodes in both examples. Compare the moments of inertia relative to these initial conditions...
I hope this helps.