VIBRATORY POWER-FLOW THROUGH A NONLINEAR PATH INTO A RESONANT RECEIVER

Vibratory power flow through a nonlinear path into a resonant receiver is considered via a specific vibration isolation example case, the au tomotive hydraulic engine mount. System equations for the source-nonli near path-receiver system are developed based on prior experimental an d analytical studies. For periodic excitation, an efficient solution m ethod is formulated for the calculation of the steady-state stable res ponse using a multi-term harmonic balance approach with condensation a nd continuation. In this computational study it is shown that, while m odeling the isolation path with a ''softened'' nonlinear expression ma y only moderately alter the predicted system behavior at the excitatio n harmonic, it can significantly alter it at higher harmonics. Computa tional studies of multi-harmonic motion and power transmission show th at audible structure-borne noise may be generated from subaudio freque ncy excitations due to path nonlinearities. It is also observed that s upport base (receiver) resonances can significantly affect the overall dynamic behavior. For instance, with a multi-degree-of-freedom base m odel, significant levels of vibratory energy at higher harmonics of th e excitation are transmitted through the path, especially when these h armonics coincide with the natural frequencies of the receiver. (C) 19 97 Acoustical Society of American.