Baseband methods of component mode synthesis for non-proportionally damped systems

This paper presents several new baseband methods of component mode synthesis (CMS) for non-proportionally damped systems. In contrast to most existing CMS approaches, these methods are based upon a first-order state-space formulation which engenders complex-valued modal vectors, transformation matrices, and reduced structural matrices. Two new methods are presented. These are baseband versions of 'constraint modes' and 'residual flexibility' methods. The constraint modes method is applicable when existing finite element matrices can be employed for analytical implementation. The residual flexibility method is used within an experimentally, based implementation with test data. The experimentally based methodology produces matrices that are compatible with the analytical matrices; thus, system models comprising both types of matrices can be analysed as a single assembly. Theoretical developments are presented in this paper and conclusions are drawn.