VARIABLE STIFFNESS NONLINEAR ISOLATOR: DESIGN, ANALYSIS AND SIMULATION

It is difficult for a conventional linear isolator including an elastic element in parallel with a damper to prevent the low frequency vibration band. Hence, this work will design, analysis and simulate a variable stiffness nonlinear isolator (VSNI) with air spring. The main feature of the VSNI is that the isolated object is supported by a mechanism including wedge-roller-air spring (named the main mechanism-MM) meanwhile the model of VSNI can obtain the lower resonance frequency and the higher vibration attenuation than the equivalent linear isolation model (ELIM) but guarantee the load bearing capacity through introducing a cam-roller-air spring (named auxiliary mechanism-AM). Because the pressure in air springs is the key parameter which is used to adjust the stiffness of the MM and AM, the influences of the pressure on the restoring force and the dynamic response of the VSNI are presented. Furthermore, the effect of the isolated load on the isolation response of the VSNI is investigated. For this purpose, the complex stiffness of the air spring will be analyzed. Next, the motion equation of the system will be built. The numerical simulation of the vibration transmissibility of the proposed model will be performed through fourth-order Runge-Kutta algorithm.