Quiet product design using optimized broadband vibration absorbers

A method for the optimization of multiple attribute noise control problems including broadband applications with broadband vibration absorbers is presented here. Specifically, the method has the ability to optimize structures with acoustic objectives over a broad frequency band, containing many closely spaced natural frequencies. It has been shown in the literature that the effective bandwidth of tuned absorbers can be extended by closely spacing many degrees of freedom in frequency, but no method had been provided to efficiently optimize such a possibility.; An efficient and robust, dynamic reanalysis algorithm was created to reduce the computational cost of optimization, including the ability to accommodate the rotational effects of the added vibration absorbers. Conjoint analysis was introduced to aggregate the multiple objectives into a single objective function, and a non-gradient optimization algorithm was used to search the design space.; Vibration absorbers were effectively optimized for three different noise transmission cases on panels using the reanalysis method with sound power as the objective. Experimentally, reductions in sound power ranged from 3 to 10 dB with less than 5% added mass for all three cases. A multiple attribute optimization was performed on an industrial pressure vessel. The optimal design was found to be materially different than the single attribute design. The number of beams added to the structure was reduced by 40% from the single attribute design without a small penalty in acoustic performance.