IDENTIFICATION OF RIGID-BODY INERTIA PROPERTIES FROM EXPERIMENTAL-DATA

The estimate of mass properties from the massline characteristic of ex perimental FRFs has attracted the attention of the modal analysis comm unity during the last decade. The problem is typically non-linear and, in the technical literature, iterative and direct methods were propos ed for its solution. In this paper a direct procedure is developed. Th e non-linear problem is divided into a series of simpler linear proble ms and solved in subsequent steps. A careful analysis is performed on the conditioning of the systems to assess the minimum number of requir ed measurements necessary to solve the problem even in noisy environme nts. The proposed approach produces accurate results for two real expe rimentally tested systems: a 2- and a 3-D structure. An accurate measu rement of the masslines characteristics is required. An extended discu ssion on this point is presented with particular emphasis on the bias introduced in the low frequency range when testing free structures. (C ) 1996 Academic Press Limited