Study On Vibration Isolation Mechanism Of Quasi-zero Stiffness Vibration Isolator Based On Normal Force Mechanism

Vibration is inevitable phenomenon in engineering practice,severe vibration can cause bad influence to mechanical equipment,such as submarines,ships,aircraft,vibration of the work to the hull and the damage caused by the body,and in this paper,the author studies on wind tunnel airflow simulation test of the position sensor of vibration,has great effect on the accuracy of the test.Therefore,in order to ensure the safe and stable operation of the equipment and improve the testing accuracy of the equipment,it is very important to effectively control the harmful vibration of the mechanical system.Vibration isolation technology has a wide range of applications in engineering.The common linear vibration isolator is simple in structure and easy to assemble,but the vibration isolation effect is not good and the low frequency vibration isolation effect is poor.Although the traditional quasi-zero stiffness vibration isolator can realize low frequency vibration isolation,it has some disadvantages such as complex structure.In order to solve these problems,this paper proposes and designs a quasi-zero stiffness vibration isolator based on normal force mechanism,and carries out vibration isolation test research.The main research contents of this paper are as follows:(1)A quasi-zero stiffness isolator based on normal force mechanism was proposed and designed.The quasi-zero stiffness characteristics of the designed isolator were verified by ANSYS buckling analysis.The influence of structural parameters on the quasi-zero stiffness characteristics is determined through parameter influence analysis.(2)For the quasi zero stiffness vibration isolation system,the dynamics analysis was carried out,and the harmonic balance method was used for numerical solution.The amplitude-frequency characteristics of the vibration isolation system were studied,and the effects of stiffness,damping ratio and excitation amplitude on the jump frequency of the system were considered.The cantilever beam-vibration isolator-vibration isolation mass system was established.The dynamic simulation analysis of the cantilever beam and the vibration isolation mass under the same excitation condition was carried out by using the finite element method.The amplitude frequency,transient and steady state responses of the cantilever beam and the vibration isolation mass were compared,thus verifying the good vibration isolation effect of the quasi zero stiffness vibration isolator.(3)According to the movement characteristics of the support rod in the wind tunnel(the support rod presents a certain Angle change),the Angle change of the support rod will reduce the pressure of the vibration isolator and affect the vibration isolation effect.The lever principle is proposed to reduce the influence of the Angle change of the vibration isolator on the vibration isolation effect.(4)On the basis of the above simulation analysis,a stiffness characteristic test rig was built for experimental research,which was verified by comparison with the simulation results;The dynamic test bed was built to carry out the transient knocking test of the vibration isolation system,and the vibration isolation mass-stiffness curve was obtained,and the optimal vibration isolation mass was found.The acceleration transmissibility test of the vibration isolation system was carried out on the cantilever beam,vibration isolator and vibration isolation mass system dynamics test bed to verify the excellent vibration isolation effect of the quasi zero stiffness vibration isolator.