Response Calculation in Zero Memory Nonlinear System Based on Digital Filter Method

Abstract

Abstract Analysis of dynamic characteristics of structures often relies on linear theory in many practical applications. However, almost all structures show nonlinear characteristics when experienced with large enough excitations. Firstly, calculation of forced response in linear dynamic system using digital filter method is presented. Then, linear system is extended to nonlinear system. The nonlinear restoring force is treated as external loads and used to derive a generalized mathematical model to calculate the forced response in zero memory nonlinear system based on digital filter method. Finally, the ‘Reverse Path’ and multiple coherence function are used to estimate the frequency response function of underlying linear system. Numerical simulation of a multiple degree of freedom system with multiple nonlinear elements is used to verify the presented method. The results indicate that the presented model works well for calculating the forced response in zero memory nonlinear system.