Sliding Isolation System Vibration Nonlinear Analysis

In nature, a sliding friction system is a nonlinear vibration one, there are still many problems, in theory and practical engineering, to be solved. Based on summarizing correlative literatures published by China and foreign countries, analyses for nonlinear vibration of the sliding-isolated system are emphatically developed in this thesis, includes:1. Based on the nonlinear vibration theory and numerical methods, autonomous vibrant phase plane characteristics of Duffing sliding system are investigated; the laws of the stagnant area length and residual deformation of the system with the variation of system parameters and initial conditions are studied , so as to provide references for systematic performance design.2. Considering Duffing sliding system excited by double-frequency harmonic excitation, employing the superposition theorem as criterion, systemic nonlinear factors and the range of parameters are discussed. The dynamic responses of the system subjected to double frequency harmonic excitation are considered as "standard response", and those obtained by means of superposition of the dynamic responses, subjected to single frequency harmonic excitations, respectively, are considered as "synthesized response". By judging the degree of the agreement between the "standard response" and "synthesized response", the applicability of the superposition principle is evaluated and system vibration non-linearity is identified.3. Taking a five-mass sliding-isolated structures, excited by El Centro and Taft earthquakes, respectively, as examples, the acceleration response spectra of superstructure considering system parameters and types of earthquake are computed and analyzed. And the results are compared with the response spectra of traditional non-isolation structure.In the end, the prime conclusions and the further issues on theory and practice are provided.