FRF Based Structural Modification of a Mechanical System by Adding Masses and Utilizing the Grey Wolf Optimization Technique

Abstract

Resonance and anti-resonance frequencies are important parameters that determine the dynamic behavior of mechanical systems. The change of these parameters, which depend on the physical properties of the system such as mass and stiffness, also changes the dynamic behavior of the system. Finding the necessary structural changes to adjust the resonance and anti-resonance frequencies of a system to the desired values is the subject of the inverse structural modification workspace. In this study, a method is presented for calculating the masses required to shift these frequencies to the desired values. The presented method uses the frequency response functions (FRFs) of the original system. For one modification an exact solution can be obtained and for two or more modifications some nonlinear equations have to be solved. For the solution of these nonlinear equations in this study, a meta-heuristic optimization technique grey wolf optimizer is used. The validity of the method was shown on a system of six degrees of freedom consisting of masses and springs and successful results were obtained. Also, it can be said it is very convenient for practical applications as the presented method uses the FRFs of the system directly.