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 criteria to select target modes, i.e. the significant modes of a base driven structure such as a payload at launch. Ultimately this concept is used as a modal reduction technique. Effective mass sensitivities give a first-order approximation of the new values of the effective masses induced by a structural modification and can be used in the design phase to avoid reanalysis of the complete model. In the paper a procedure, 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 procedure some outputs are compared with the standard Nastran ones for a spacecraft structural model. The results show a good agreement and qualify the procedure as very reliable.