The Research On Transmission Ratio Of Simple Vibration Isolation System By Continuous System Theory

Traditional researches about vibration isolating devices are often focused on discrete isolators. But because of the distributing parameter characters of the isolators and the raft supports, the factual projects request continuous isolator model. This has been recognized more and more in the researches on the middle- or high-frequency vibration and on the acoustic transmission. Base on the developing equation of finite Timoshenko beam's wave solution, the continuous system theory is used to study the isolator and the raft supports. There the isolators are modeled as discrete elastic elements, Euler beam and Timoshenko beam in studying the vibration isolating systems. And flexural motion and longitudinal motion are also investigated. Then the force transmission ratio of the systems are analyzed and calculated. Then on the foundation of two finite element floating raft system models, the force transmission ratio, natural frequency and model shape are analyzed.Finally this thesis shows that the shear deformation and rotary inertia must be considered when study a thick isolator at higher frequency and the characters of the isolator's and the raft supports' distributing mass also must be considered.