Structural Dynamic Frequency Response Using Combined Direct and Adjoint Reduced-Order Approximations
A second-order combined approximate-direct/approximate-adjoint method for efficient reduced-order calculation of frequency response in structural dynamics is presented. The method is design oriented. It focuses not only on the response itself (in the form of displacements and, especially, stresses) but also on sensitivities of the response with respect to structural design variables. Comparisons of approximate results obtained by mode-displacement order reduction, reduced-order adjoint solutions based on Ritz vectors, and the second-order approximate method demonstrate the accuracy of the second-order method, and provide lessons that suggest directions for future research.