ENERGY-FLOW PREDICTIONS IN A STRUCTURE OF RIGIDLY JOINED BEAMS USING RECEPTANCE THEORY

A method for evaluating the energy flows in a general network of beams , based on receptance theory, is presented. The behaviour of the globa l structure is predicted from the Green functions of the individual un coupled beams, evaluated as summations over their mode shapes. This pe rmits analysis of structures having localized properties or those wher e the modal information is derived numerically (e.g., by the use of fi nite element analysis). The method is implemented as a computer progra m and aspects of numerical problems regarding Green function convergen ce and the extraction of higher modes are discussed. In the second hal f of the paper, a cantilever structure of 16 beams with eight joints i s subjected to point harmonic forcing at a joint. The velocity respons es at a joint remote from the point of forcing are compared against th ose from a finite element model and good agreement is obtained. The ti me and frequency averaged energy levels of all the beams in the struct ure are then studied under conditions of localized damping on differen t regions of the structure, and also for changes in geometry. (C) 1995 Academic Press Limited