A STUDY ON PASSIVE LOW STIFFNESS SUSPENSION DEVICES

摘要

Suspension systems used for simulating free-free boundary conditions can have undesired effects on the dynamics of the supported structure. If the stiffness of the suspension system is close to the stiffness of the structure, the structure's tow frequency modes of vibration will increase in frequency resulting in uncertainties about the frequency of the structure's modes in truly free-free boundary conditions. Also, because suspension systems have dynamics of their own, it is important to design these systems so that their dynamics occur outside of the frequency range studied for the test structure. A dynamic analysis of two suspension system designs is presented to reveal how these systems are capable of suspending large loads while allowing these loads to move freely. The Zero Spring Rate Mechanism is one of the suspension devices studied. However, in an attempt to reach low suspension frequencies, the Zero Spring Rate Mechanism failed as a practical design. The Cantilever Suspension System was also studied and was found to be a more practical device for simulating free-free boundary conditions.