Substructure Synthesis Methods and Their Application to Structural-Acoustic Simulations

Abstract

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Abstract: An overview of impedance-and modal-based substructure analysis techniques used in the Structural Acoustics Department is presented. The impedance technique described herein offers a substantial advantage over other coupling techniques because it is uniquely suited to handle data sets of varying origin. Of particular interest is the combination of numerically and experimentally derived frequency response data, which is especially useful for analyzing structures comprised of components too complex to model using the finite element technique. The impedance-based method is derived from the frequency domain substructure synthesis algorithm introduced by Jetmundsen et al [1], which offers a significant improvement over the traditional frequency domain technique in terms of the processing requirements. The modal-based methods involve the coupling of substructure eigenanalysis results to arrive at coupled system (complex-valued) eigenvectors and allow forced response simulations for the coupled system. This method offers an alternative to traditional techniques employed by commercial finite element codes. Limitations of both techniques are identified and discussed along with potential methods for avoiding these shortcomings. Several example problems are presented that show each method's usefulness.Hi