Force Appropriation by Extended Asher's Method

Force appropriation is used in modal vibration testing of complex structures in order to excite one mode of vibration at a time. In this paper several force appropriation algorithms are reviewed and an extension of Asher's method, using impulsive and transient excitation as well as sinusoidal excitation, is developed. The number and location of exciter and measurement points can be different with the extended Asher's method which promises to be relatively free of the false resonant frequencies that occasionally affect the standard Asher's method.