A close examination of high-frequency residual terms trends

Abstract

In order to use response data such as frequency response functions (FRFs) in further dynamic analysis without introducing large errors, it is important to correctly predict the levels of vibration involved. To that end, an understanding of residual mode information is essential. Although the effects of neglecting residual terms are known and some solutions to this problem already exist, there is a lack of full understanding of their trends for a deeper and better solution to this problem. When are residual terms really important? To answer this question, a thorough investigation was undertaken to discover new residual term trends and to study some known ones. Only high-frequency residual terms are investigated in this paper. Their importance at resonance and anti-resonance, at point and transfer FRFs, as well as at translational and rotational FRFs, is investigated. A relationship is shown between the mass of the system and the high-frequency residual terms and this is the base for the formulation of the high-frequency residual term developed by the author, called the mass-residual approach. Examples are given at the end of the paper to illustrate and clarify the trends presented.