Optimize The Design, Based On The Stochastic Structure Of The Frequency Of Reliability Constraints

The history and research of optimum design for dynamic characteristic of structure are reviewed firstly. Then the defect of conventional optimization is proposed. That is to say, engineering structure should be looked as random structure, and optimum design for dynamic characteristic of structure must be based on reliability. Applying Monte-Carlo method to simulate random fields. Numerical results is consistent with reliability theory. Applying spectral decomposition of correlation matrix theory, an equation of structure dynamic characteristic optimization considering the randomness of physical parameters(elastic module and mass density) of structural materials is proposed. Digital characteristic values (mathematical expectation and variance) of eigenvalues are derived from dynamic equation, and eigenvalues derivatives are evaluated, then sequential quadratic programming method(SQP) is applied to structural optimization. Results show that it is of excellent properties. Finally, computer-aided engineering method(CAE) is introduced, and ANSYS parametric design language(APDL) is applied to structure dynamic characteristic optimization based on reliability. The analysis of three examples show feasible.