A PROCEDURE FOR THE DETERMINATION OF EFFECTIVE-MASS SENSITIVITIES IN A GENERAL TRIDIMENSIONAL STRUCTURE

In the aerospace community effective mass is the most commonly used cr iteria to select target modes, i.e. the significant modes of a base dr iven structure such as a payload at launch. Ultimately this concept is used as a modal reduction technique. Effective mass sensitivities giv e a first-order approximation of the new values of the effective masse s induced by a structural modification and can be used in the design p hase to avoid reanalysis of the complete model. In the paper a procedu re, based on modal expansion, for yielding the effective mass partial derivative with respect to the structural lumped mass, developed for a general tridimensional structure, is described. To validate the proce dure some outputs are compared with the standard Nastran ones for a sp acecraft structural model. The results show a good agreement and quali fy the procedure as very reliable. Copyright (C) 1996 Elsevier Science Ltd.