Dynamic performance of a novel hydraulically damped rubber mount with inertial track at low frequency: modeling and experimental study

To suppress the vibration of the suspended cab of construction machinery, a novel passive hydraulically damped rubber mount (PHDRM) with multi-inertial tracks is designed. The two suspension system models describing single and multi-inertial tracks are proposed in different coupled relations based on the parallel combination model of rubber and fluid, considering fluid rheological behavior and compressibility. The low-frequency dynamic behaviors of the PHDRM and rubber isolator with corresponding structures under fixed-frequency and frequency-sweep excitations are investigated analytically and experimentally. It is demonstrated that the dynamic stiffness of PHDRM exhibits softening characteristics, as well as amplitude and frequency dependence, which are caused by the viscoelastic behavior of hydraulic oil and fluid-solid coupling. And the damping has a more significant amplitude and frequency dependence. The results also illustrate that PHDRM exhibits more excellent dynamic performance in suppressing vibration and resonance compared to the traditional rubber isolator. The effectiveness of the mathematical model is verified by comparing the simulation and experimental results. Further, the dynamic performances of the PHDRM with different lengths, cross sections, and numbers of inertial tracks are studied by using measured force-displacement loops and transmissibility, and their vibration isolation performances were compared. Experimental results show that the PHDRM with three inertial tracks has significant advantages in energy dissipation, resulting in better predictions in reducing transmissibility. The studies in this paper provide an important theoretical basis and reference value for the structural optimization design of the hydraulically damped rubber mount.