Nonlinear vibration isolation performance enhancement using elastic constraint and linkage mechanism

Abstract

This research presents nonlinear vibration isolators with elastic constraint included in linkage mechanism with geometry nonlinearity. The vibration attenuation enhancement of integrating nonlinear elements to a single-stage isolation system and an isolation system with flexible foundation considering the applications in marine engineering or aerospace engineering is investigated. The harmonic balance method (HBM) with the Alternating Frequency/Time (AFT) scheme and a time-marching method are employed to calculate responses. The vibration transmissibilities and power transmission indices are taken as measures of isolation performance. The results show that the nonlinear isolator dramatically decreases power flow and vibration transmissibility to the base in a broad frequency range. The use of the elastic constraint enables wider ranges of parameters of spring-linkage in design and the proposed isolator can provide improved vibration attenuation capabilities in low frequencies. By a collaborative design using the elastic constraint and linkage mechanism, the peaks in curves force transmission and power flow to the flexible foundation can be significantly suppressed and shifted towards lower frequencies. The study demonstrates that the proposed isolator designs can be further applied in the isolation platform of mechanical systems on board.