The basic principle of Component Mode Synthesis (CMS) substructuring methods is to reduce each component into a smaller set of generalized coordinates by pre- and post multiplying the system matrices with a well-chosen transformation matrix and to assemble the obtained superelements. As the number of coordinates of the assembly is relatively low, fast evaluation of the dynamic characteristics is possible and consequently, optimization of the dynamic behavior of the assembly becomes feasible. The latter however requires that one can efficiently implement structural modifications without going again through the component reduction process. This paper explains how modifications can be efficiently evaluated for assemblies composed of reduced CMS models. The underlying idea of the proposed approach is to use the component transformation matrices to project the mass and stiffness modifications to the size of the superelements. The paper illustrates how the outlined approach can be employed to optimize the vibro-acoustic behavior of a subframe-body-cavity assembly.
