Power Flow Transmission Analysis Of Nonlinear Isolation System Based On Flexible Foundation

As the nonlinear vibration theory is applied more and more widely in projects, further analysis, research and optimum design on intricate nonlinear vibration system is regarded as the most challenging and prospective work in the field of vibration and noise control. Meantime, the research and analysis on the problem of structure vibration and noise control with the method of power flow becomes the most interesting contemporary hotspot. This dissertation, based on the knowledge of domestic and abroad progress in the vibration control technology and application, carried out a research work on the vibration characteristics and control strategy of the nonlinear system established on the flexible base.Respectively, this dissertation illuminated some introduction and analysis about flexible rectangular thin plate, nonlinear vibration and evaluative method of power flow, based on which a nonlinear vibration isolation system composed of power machine, nonlinear vibration isolator and flexible base is established. Excited by the excitation of simulation, the system will vibrate in nonlinear form, then the differential equation of the whole system could be carried out by analyzing the vibration modalities of each part. Concerning the research method ,harmonic balance method and Newton iterative method are applied to carry out the differential equation, with the results of which we can calculate the power flow transmitted to the flexible base from the excitation. Finally, the transmitted characteristics of power flow are gained by analyzing and comparing the different graphs of frequency which are related with the nonlinear parameters. The great innovation of the dissertation is that the influence of the super harmonic to the transmission of the power flow is considered. With the help of the above research, the vibration control strategy of the system and the optimum design principle of the nonlinear vibration isolator are carried out.According to the compare of the power flow transmission in various conditions such as linear and nonlinear vibration isolator, different nonlinear rigid and damper characteristics parameters, considering main harmonic only and as well as added super harmonic, it reveals : if considering the main harmonic only, when the ratio of frequency(the excitation's and the base's) is smaller than 1, the perfonnance of the nonlinear vibration isolator is better than the linear isolator and the nonlinear rigid characteristic parameters larger than 1 and the nonlinear damper characteristic parameters smaller than 1 are best to vibration isolation; when the ratio is larger than 1, it's sensible to chose the nonlinear characteristic parameters larger than 1. On the other hand, if considering both of the main harmonic and partial super harmonic, it is optimum to chose the nonlinear characteristic parameters smaller than 1 when the ratio is smaller than 1 and the nonlinear characteristic parameters larger than 1 when the ratio is larger than 1.