Finite element implementation of linear modification method for local structural modification

This paper discusses the latest development of Linear Modification Method (LMM) for local structural modification. LMM is based on the solution of linear simultaneous equations. It was formulated for the modification of a mass and spring like dynamic systems. The method was presented in two papers published on previous IMAC proceedings. In this paper, the method is extended to a general structural system where feasible structural modification is implemented by changing physical parameters such as cross-sectional area of a truss element or thickness of a beam element. This is a significant step forward since for real structures, simple changes of mass and stiffness properties may not be realistic. The techniques developed for truss and beam structures can be applied to other structural modification cases and objectives. A number of examples are given in this paper to demonstrate the feasibility of LMM.