Predicting Acoustical Noise Generation in Complex Mechanical Systems

Abstract

A fundamental study of noise generation in complex mechanical systems is undertaken. The objective of the study is the development of design guidelines for the prediction of mechanical system noise levels. Recently developed dynamical procedures are used to obtain the motions of linked mechanical systems with elastic elements and connection clearances. An analytical procedure for modeling the acoustical noise generated by complex mechanical systems is applied to a typical linked system, a four-bar mechanism. The far field acoustic pressure distribution is calculated and shown to be a function of many of the parameters under the control of the system designer. To aid the designer in producing quieter systems, acoustic design functions are developed. In particular, the system sound power and modal power efficiencies are found to be promising design tools.