Jacek Michalski

Control arm analysis - fixtures

Discussion created by Jacek Michalski on Feb 1, 2021
Latest reply on Feb 15, 2021 by Shawn Mahaney


I have a question regarding fixtures in case of control arm analysis. Here's an image showing constraints applied to the model:


The following fixtures were defined:

1) on cylindrical face (for internal cylindrical face of each rear bushing) - only radial direction is restrained (this leaves 2 rigid body motions of the part: translation and rotation in X axis)

2) roller (for two planar faces of each rear bushing) - this eliminates the translation in X axis, rotation about this axis is still possible

3) roller (for back planar face of front bushing)


Now for me it seems that this last fixture can't eliminate the remaining rigid body motion (rotation about the X axis). And yet the analysis completes and there are no RBM's visible in modal analysis. How is that possible ? Does the last fixture (number 3) somehow eliminate the rotation about the X axis ? If yes then how (I can't see this) ?


My idea is that the third fixture makes it impossible for the back planar face of front bushing to leave the XY plane (lean against it). Is that correct ?


Thanks in advance for your help