EXPERIMENTAL EVALUATION OF VARIOUS NORMAL-MODE FORCE APPROPRIATION METHODS ON A RECTANGULAR PERSPEX PLATE

Force appropriation methods aim to provide an estimate for the force d istribution required in order to excite a 'pure' normal mode in a vibr ation test using multiple exciters. In this paper, experimental result s from various direct methods which use the measured Frequency Respons e Function matrix to determine the force distribution are presented. T wo different rank reduction approaches were included. The test set-up consisted of a rectangular perspex plate with close modes of vibration , using 24 accelerometers and 4 exciters. Force distributions were obt ained which compared well with theoretical predictions and several goo d quality normal mode shapes were excited.