An Improved Dynamic Impedance Method for Dynamic Analysis of a Vehicle 931314

It is generally recognized that a composite dynamic impedance method using component frequency response functions obtained experimentally is an effective procedure for analyzing complex dynamic systems extending over a wide frequency range. However, previous attempts to apply composite dynamic impedance methods to analyses of dynamic systems involving multiple connection degrees of freedom for several components have been largely unsuccessful because of numerical error that occurred in the matrix inversion process. In an effort to avoid this problem, researchers at Structural Dynamics Research Corp. have recently proposed an improved composite dynamic impedance method known as SMART, an acronym for System modelling and analysis using the response technique. SMART incorporates the singular value decomposition (SVD) theorem as a numerical technique for reducing error in matrix inversion.

Another approach that has frequently been used to avoid the above-mentioned problem is the complex vector method, which provides a simple technique for making approximate dynamic response predictions. The complex vector method ignores the dynamic coupling among connected components and so does not require matrix inversion. In this paper, SMART and the complex vector method are applied to an actual vehicle problem and the simulation accuracy of each method is confirmed, dependant upon the degree of dynamic coupling between components. It is shown that efficient solutions can be obtained through the selective use of the two methods.