Effects of distributed structural dynamic modification with reduced degrees of freedom

Abstract

The aim of this study is to investigate means of efficiently assessing the effects of distributed structural modification on the dynamic properties of a complex structure. Although structural modification has been demonstrated as an efficient method for one-dimensional distributed modification with/without additional degrees of freedom (DOFs), like beam modification, research into structural modification of two-dimensional (2D) structures and/or with reduced DOFs has been limited. In this paper, structural modification has been applied to a plate clamped on all four edges in which a rectangular hole is cut out in the center as modification. The frequency response functions (FRFs) of the original unmodified plate were obtained experimentally as well as numerically. The delta dynamic stiffness matrix was determined numerically by modeling the cut out and part of the original structure. The FRFs of the modified plate are computed by coupling the original FRFs and the delta dynamic stiffness matrix. Good agreement is obtained between the FRFs of the modified plate determined experimentally and those obtained by numerical modeling of the complete modified structure. Structural modification method has been verified on 2D structure for distributed modifications with decreasing in DOFs.