Abstract: According to the complexity and high-cost character of dynamic analysis in the processing of structural dynamic optimization, the critical time points identification method for solution space of dynamic stress based spectral element is proposed. The solution space of the structural dynamic stress is obtained by using the modal superposition method. And then, it is discretized as the spectral points about Gauss-Legendre-Lobatto. The matrices of time points and their corresponding solution space values of dynamic stress are constructed. The Lagrange interpolation techniques are applied in the solution space domain to get dynamic stress function of high precision. The absolute maximum point, which is the critical time point, is found by executing the global optimizer named DIviding RECTangles. Two examples of 124-member plane truss and the cantilever are used to illustrate the feasibility and validity of the proposed method.

Key words: dynamic stress;Gauss-Legendre-Lobatto;Lagrange interpolation;critical time points