A New Approach to Find a Transformation Matrix in Component Modal Synthesis

This paper proposes new methods to find a transformation matrix used in predicting the dynamic characteristics of large space antennas in component mode synthesis. Current methods such as the Guyan reduction use mass and stiffness submatrices to calculate the transformation matrix. In the proposed methods, the transformation matrix is derived from both the internal and boundary modes. The effectiveness of the methods is verified by applying them to a cantilever beam and a truss structure. Numerical results show that the prediction accuracy of the dynamic characteristics depends on the number of modes used in finding the transformation matrix. Accurate prediction is possible when the number of used modes does not exceed the boundary degrees of freedom considered in the same kind of modes such as out of bending modes or torsion modes.