The Dynamic Analysis On Prepressing-contact Cushion Structure

The simplified prepressing-contact spring-damping system was studied in this dissertation. The nonlinear dynamic characteristic of this system was research by experiment method.The prepressing-force is changed by the state of the prepressing-contact cushion structure, and the slip phenomenon is appeared in the vibration environment. Under the normal environment there is pressure on the vibrator, if there is tension with the vibrator the separation phenomenon would appeared. The appearance of this phenomenon can made the system lost it nature function. In order to prevent this phenomenon from occurring, it is necessary to research the rule and mechanism of production of this phenomenon.In the theoretical analysis, first the dynamics model of the prepressing-contact spring-damping system was established by vibration theory. Then the stability of the solution of this system was studied base on the qualitative theory of nonlinear vibration. Under the small amplitude condition, the system becomes weak nonlinear system, it can be solved by harmonic balance method, the result show that the frequency is in respect to the amplitude of vibration and the value of prepressing.In the experimental research, the experiment equipment was firstly design, and the value of prepressing can be change by adjust the distance of two soleplates. Secondly a harmonic excitation was added on this equipment, receding the response of displacement and acceleration. Then the experimental data was analyzed in time domain and frequency domain. Thirdly the Hilbert translation method was used to detect the nonlinearity of the system. At last the model of this kind of system was identified, the result show that the theory model is the same format as the experiment model.At last, in according to the experiment results, the interpretation of the mechanism of the slip phenomenon of prepressing-contact spring-damping system was given in this dissertation. Further more, the relationship among the limit frequency, the value of prepressing, excitation frequency, the amplitude of excitation and the materiel parameter was analyzed. Base on the theory analysis the limit frequency formula was given, and the contact-slip condition for engineering application was concluded.