About eigen sensitivity analysis of mechanical structures

Several methods for a calculation of derivatives of eigenvectors with respect to design parameters are described here. These are the finite-difference method, the modal method, a modified modal method, Nelson's method, an improved first-order approximation of eigenvalues and eigenvectors and an iterative method. By combining the other structural reanalysis techniques and one of these sensitivity methods, it is possible to enhance the efficiency and the accuracy of structural optimization techniques for determining the optimum condition of mechanical structure specified by an analyst. The sensitivity approach is based on the prior selection of updating parameters (design variables) in the initial FE model.