Vibration isolation performance and non-probabilistic reliability evaluation of multidimensional vibration isolator with interval joint clearance

For suppressing multidimensional vibration effectively, the multidimensional vibration isolator based on parallel mechanism considering interval joint clearance is proposed. The kinematics and dynamics of the isolator are established respectively. The contact force generated due to interval joint clearance is modeled respectively by the Lankarani–Nikravesh (L-N) model and the modified Coulomb friction force model. Furthermore, the dynamics of the isolator with interval joint clearance are obtained by the first order interval perturbation method. The upper and lower bounds of vibration isolation performance are calculated, which indicates the isolator with interval joint clearance inhibited external vibration in time and frequency domain respectively. The vibration isolation performance is most sensitive in pitch (around $x$ ) direction due to the existence of interval joint clearance. The non-probabilistic reliability model of the isolator is proposed by the shortest distance method, and the non-probabilistic reliability index is investigated in each isolation direction with interval joint clearance. The reliability index of the isolator exhibits a quasi-stable area in horizontal (in $x$ ) and pitch (around $x$ ) directions, which implies the reliability index is not sensitive to joint clearance variation in a certain perturbation range. The proposed vibration isolator with interval joint clearance is fabricated, and the vibration isolation experiment is conducted. The experimental results are generally consistent with the theoretical results, which indicates the correctness of the analysis.