Adaptation of the concept of modal analysis to time-varying structures

The elegance and global character of modal analysis make it very attractive for adaptation to time-varying systems. Most of the concepts of modal anal ysis are well established in literature and widely understood for linear ti me-invariant systems. This paper discusses an adaptation of modal analysis concepts to time-varying systems. A typical contemporary example of a time- varying system is a flexible space manipulator or a reconfiguring space str ucture. An approximation of a time-varying transfer function is introduced by making assumptions about its variability. This approximate transfer func tion is referred to as a pseudo-transfer function. The modal parameters ass ociated with the pseudo-transfer function are referred to as the pseudo-mod al parameters. This paper discusses the validity and the extent of applicab ility of pseudo-modal parameters. (C) 1999 Academic Press.