OPTIMIZATION DESIGN OF 3D RANDOM STRUCTURES UNDER RELIABILITY CONSTRAINTS OF EIGENVALUES

摘要

Combining recursive stochastic finite element method with the design point method (JC),a new method of calculating structural reliability index is presented based on non-orthogonal polynomials expansion of dynamic characteristics of random structures. Then the optimization design model of three-dimensional structures with random parameters is set up under reliability constraints of frequency or forbidden frequency domain. In this optimization design model, the minimum weight of the structure is chosen as the objective function. Further more the random optimization model is transformed into deterministic optimization model that can be solved by sequential quadratic programming algorithm. In the end, a 3-D cantilever beam example is shown to illustrate the effectiveness of the new method and some meaningful conclusions are obtained.