Modeling and experimental verification of frictional contact-impact in loose bolted joint elastic structures
Foster, John T.
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Presented in this thesis is an investigation into the dynamic behavior of a mechanical joint contained within a flexible structural system given additional degrees of freedom by allowing the joint to be "loose'" while in motion. While allowing a mechanical joint to be "loose" may be counterintuitive to a mechanical designer and trying to accurately model one may seem like only an academic exercise, it brings into consideration an important topic in modeling dynamic systems in the form of constraint addition and deletion. These constraint additions and deletions commonly present themselves in physical systems. Another motivation for this study is the fact that joints commonly wear while in service and can become “loose." Understanding the dynamic effects of these "loose" joints could make system control more robust. The combination of flexible beams on either side of the rigid joint classifies the mechanism as a hybrid parameter multiple body system. The system was modeled mathematically using a recently developed hybrid parameter multiple body system modeling method and frictional contact/impact algorithms which incorporate the idea of instantaneously applied non-holonomic constraints. An experimental mechanism was constructed for verification of the math model.