Research On Dynamics Performance And Optimal Design For Constrained Damping Vibration Isolator

Constrained damping vibration isolators are widely applied in engineering. Stiffness and damping are two important dynamics performances of the vibration isolator, which would be the critical factors in vibration isolation and stability of the device. In order to ensure devices working stably in environment of intense vibration and disturbance, the research in dynamic performance of vibration isolators is required. Recently,the structure dynamics analysis about the isolator has been an important methods in engineering application, including a set of programs consisting of structural modeling, analysis and behavior prediction.In the thesis, the mechanic model of isolator was analyzed. Through the analysis, it is recognized that stiffness and damping are two critical dynamics factors. Then theory in type of vibration structure and viscoelastic damping material were introduced, which described importance of influence in dynamic performance of vibration isolators by structure and material parameter. And then the design process of the isolator was also introduced briefly.Energy dissipation mechanism and dynamic damping performance of viscoelastic damping material were studied in this thesis. Using fractional derivative model and temperature-frequency superposition principle, the parameterized mathematical equation were obtained, expressing the relation between complex modulus, dissipation coefficient and temperature. In the expressions, the parameters were fitted according to the experimental datum of viscoelastic damping material dynamic performance tested by Dynamic Mechanical Thermal Analyzer (DMA). Experiments results and error analysis validated the expressions.Secondly, on the basis of effect on structure dynamics property by different material, the model was established by methods of equivalent stiffness and model strain energy. This model demonstrated the relationship between structure dynamic performance and parameters of individual material. With the work done, mechanic simulation and sinusoidal sweep frequency test could be carried out. The results of simulation and error analysis by test indicated that the model could exactly reflect the relation between structure dynamic performance of vibration isolator and its material property.In the end, a topology model was advanced based on the damping structure, and geometrical factors influencing in dynamic performance had been analyzed. Supposing these factors as design variables, size optimization of the isolator was conducted by appropriate optimization method without destroy of strength and stiffness. After optimization, the structure damping performance was improved, and better damping performance under work condition was acquired.