Complex Modal Analysis of Vibrations of beams on viscoelastic Pasternak foundations
PENG Li1,2, DING Hu1,CHEN Li-qun1,3
1. Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072; 2. College of Civil Engineering, Shanghai Normal University, Shanghai 201418;3. Department of Mechanics, Shanghai University, Shanghai 200444, China
Abstract:The complex modal analysis is applied to investigate vibrations of finite beams on viscoelastic Pasternak foundations. The vibration equation of the beam is expressed in the state equation and decoupled into a set of ordinary differential equations, based on the orthogonality of the modal functions. The complex frequencies, modal functions, and dynamical responses to external excitations with any initial conditions are derived. Comparing two specific examples, with pinned supports at both ends, the characteristics of the natural frequencies and modal functions are analyzed, and through the specific modal functions, the dynamical responses to two typical external excitations are given.