Experimental study on the dynamic properties of the dual-chamber solid and liquid mixture vibration isolator

Abstract

The dual-chamber solid and liquid mixture (SALiM) isolator exhibits multiple stiffness and damping properties with various parameters. As a passive isolation device, the dual-chamber SALiM isolator can also obtain a variable stiffness property by substituting the valve with an active throttle device. Before that, the dynamic properties of the isolator need to be further investigated. Sine sweep tests under different valve openings were implemented to analyze the frequency response characteristics of the system. Two hydro pressure sensors were added into the two chambers to record the pressure signals, with which the equivalent stiffness, equivalent damping, fluid damping, and equivalent mass of the liquid column were identified. Based on the test results, numerical and theoretical analysis, the dynamic properties of the isolator including the influence of the fluid damping and inertia mass on the equivalent stiffness, the relation between the isolator's equivalent damping and the fluid damping, the fluid capacity of the linking tube, and the equivalent mass of the liquid column were analyzed in depth. Conclusions about stiffness and damping obtained from the test results correspond well with those from the theoretical analysis, but the identification results of the equivalent mass, which show that the negative correlation of equivalent mass of the liquid column with its response amplitude seems controversial. An assumption is proposed to explain the abnormal characteristics of the liquid column. However, the exact model of the inertia track needs further exploration and verification.