On identification of small defects by vibration tests

Abstract

This paper addresses the conceptual problem of whether there exist measurable quantities which are highly sensitive ta small changes in the physical parameters ofvibrating systems? We present an astonishing analytical example, showing that a small change in one of the springs of a large multi-degree-of-freedom mass-spring system can be identified by a special dynamic test. We then argue that despite this analytical example, which can be easily reproduced by ali interested readers, the longstanding controversy whether a small damage in a realistic structure can be identified by a dynamic test is still open.