Abstract
This paper presents a new evolutionary optimization method on dynamics of three-dimensional structures based on finite element modeling. An optimum structural design can be obtained from a simply small structure by allowing finite elements to be added as well as removed. The structural optimization method is developed using two kinds of sensitivity functions based on Rayleigh Quotient and strain energy. Especially, the authors take into consideration a problem of the mode-switching phenomenon that causes the convergence of the method to be difficult, and develop a way to solve the problem by a sensitivity function to consider the contribution rate of each natural mode. The method is examined using two 3 dimensional small structural models. The design objective of the examples is to shift the lowest natural frequency up to a target frequency.
