Reliability assessment of the shock isolation performance for parallel mechanisms under multi-source uncertainties

Parallel mechanisms are widely used in ships to reduce the harmful effects of shock and vibration, offering high versatility and low maintenance costs. Typically, the shock isolation performance (SIP) of parallel mechanisms is assessed by the force or response transmitted to the protected shipborne equipment. However, uncertainties in structural and geometric factors, as well as in excitation conditions, may induce random fluctuations in the response or transmitted force, potentially compromising the SIP. Accordingly, the paper proposes a reliability assessment approach for the SIP of parallel mechanisms that accounts for multi-source uncertainties. A theoretical model of the parallel mechanism is established to investigate its dynamic behavior. The sources, influence, and distribution of structural, geometric, and excitation factors on SIP are analyzed to identify the critical factors. The amplitude of the acceleration response of the parallel mechanism is selected as the evaluation metric for SIP, and a limit-state function incorporating the uncertainties of critical factors is constructed. The reliability of the SIP is assessed through an approach that integrates stochastic configuration network surrogate model and an adaptive learning strategy. In addition, the dynamic response and the reliability of the SIP in the parallel mechanism are experimentally verified. The study can provide theoretical and methodological foundations for reliability assessment of complex mechanisms under uncertain conditions.