Random Vibration + Bolt Loosening - Help Needed!
Hey everyone,
I’m working on a random vibration analysis and hitting a snag with bolt preload. From my understanding, random vibration is a linear simulation, right? So the contact is basically just open or frozen. But, when we talk about bolt preload, we’re dealing with some serious nonlinear contact between parts. This means standard random vibration can’t handle the bolt preload effect directly.
My main question is: Does anyone know of methods to account for bolt loosening (i.e., preload reduction) during a random vibration analysis? It seems like a common problem but I’m struggling with it.
Any insights or advice would be greatly appreciated!
Thanks in advance!
Answers
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STATSUB(PRELOAD) command can be used to include loading effects from a prior linear or nonlinear (small and large displacement + N2S/S2S contact only) subcase as a structure’s stiffness change. The contact status is carried over to the current subcase in which this STATSUB(PRELOAD) is defined. The preloading can be applied on linear static, normal modes, complex eigenvalue, direct frequency response, modal frequency response, direct transient response, and modal transient response solution sequences.
You can find additional information in the bellow links:
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