Research On Dynamic And Impact Performance Of Disc Spring Vibration Isolation Unit

Inertial navigation equipment can provide attitude,speed and position information for merchant ships,and is an indispensable equipment for sailing in the open sea.Inertial navigation equipment is a sophisticated electronic instrument with complex structure.In the impact environment,it is easy to damage,the navigation accuracy is reduced,and even the navigation ability is lost,which will seriously weaken the maneuverability of the merchant ship.Therefore,effective impact protection must be carried out.Inertial navigation equipment requires that the vibration isolation system can provide higher rigidity when the external load is small,and ensure the positional accuracy of the inertial navigation device.At this time,the vibration isolation effect of the vibration isolator is weak;when the external load is large,vibration isolation is required.The system has less stiffness and greater damping,which quickly unloads external loads.According to the requirements of the above-mentioned inertial navigation device for the nonlinear stiffness and damping of the isolator,a disc spring isolator with nonlinear stiffness characteristics is designed to test the cushioning performance under static,dynamic and impact environments,and the test results will be tested.It is brought into the eight-bar parallel simulation model to verify whether the performance parameters of the disc spring isolator meet the requirements of the inertial guidance equipment for the performance of the vibration isolation system.The main research contents of this paper are divided into the following points:(1)A disc spring isolator with two-way vibration isolation characteristics is designed.It is found through static loading test that the disc spring isolator has the characteristics of stiffness becoming softer with increasing displacement.It is proved that the internal preload of the disc spring isolator can be enhanced to enhance its static stiffness.Finally,the influence of internal lubrication conditions on its static performance is studied.The results are summarized and optimized to maximize the static stiffness of the disc spring isolator.(2)In the frequency sweep test,the natural frequency of the isolator is reduced as the excitation load increases.At the same time,the jump phenomenon of the transmission curve of the disc spring isolator is found,and the jump interval is on the left side of the natural frequency.It shows that the stiffness of the isolator decreases as the input load increases,that is,the soft spring.Finally,the nonlinear stiffness and nonlinear damping fitting formula of the disc spring isolator are determined in the impact test.The results show that the damping of the disc spring isolator increases with the increase of the impact load.(3)Combined with the theoretical method and the finite element method,the fatigue life of the disc spring isolator in the limit case is obtained.The research results have important guiding significance for the maintenance work of the isolator.(4)An eight-bar parallel simulation model was built to incorporate static,dynamic,and shock buffer performance parameters.The simulation results show that the eight-bar parallel model has higher stiffness in static environment,stiffer stiffness in impact environment,and acceleration isolation rate of 67% under standard impact load.These conclusions indicate that the model conforms to inertial navigation.Equipment requirements for vibration isolation cushioning performance.The simulation results of the eight-bar parallel model verify that the disc spring isolator has superior static and dynamic vibration isolation cushioning performance.Compared with the traditional vibration isolators,the characteristics of low load and large stiffness and high load and low stiffness are very significant,and the damping is high under impact environment.These characteristics are in line with the requirements of the eight-bar parallel model for the buffer unit.