Extended Layout of Stiffeners to Increase Fundamental Frequency of Shell Structures

Abstract

Structural Dynamics Modification (SDM) is to improve dynamic characteristics of a structure, more specifically of a base structure, by adding or deleting auxiliary (modifying) structures. In this paper, the focus will be concentrated on the optimal layout of the stiffeners which are attached to the plate to maximize 1st natural frequency. Recently, a new topology method was proposed by yamazaki. He uses growing and branching tree model. In this paper, to overcome limitations of the method, modified tree model will be suggested. To expand the layout of stiffeners, non-matching problem will be considered. The problem is solved by using local lagrange multiplier without the mesh regeneration. Moreover CMS(Component mode synthesis) method is employed to reduce the computing time of eigen reanalysis using reduced component models.