Reliability evaluation method of vibration isolation performance of nonlinear isolator

Nonlinear isolators are widely used to reduce harmful vibrations due to their broad isolation bandwidth. The vibration isolation performance of nonlinear isolators can be quantitatively evaluated by the transmitted force or displacement. However, uncertainties exist in the excitation and structural factors of nonlinear isolators, which cause the dispersion of displacement and force transmissibility, and affect the vibration isolation performance of nonlinear isolators. In this paper, a reliability evaluation method of vibration isolation performance of nonlinear isolator is proposed by considering the influence of the uncertainties. First, quasi-zero stiffness characteristics of the nonlinear isolator is analyzed and a dynamic model is established to study the isolation performance of the nonlinear isolator. Then, the types, sources, and influence degrees of the uncertainty of dimensional, structural, and excitation parameters on the nonlinear isolator are studied, and sensitive parameters are extracted. Furthermore, the reliability model of the nonlinear isolator under the action of sensitive parameters is proposed by considering the amplitude of the steady-state displacement response of the nonlinear isolator as the evaluation index of vibration isolation performance. Finally, the reliability of the nonlinear isolator is evaluated using an advanced surrogate model method based on stochastic configuration network. An experimental platform is built to verify the validity of the reliability evaluation method. The proposed method can provide potential guidance for the reliability evaluation of the isolation performance of complex nonlinear isolators.