The Quasi-Zero Stiffness Seat Vibration Isolator Design to Improve Cockpit Vibration Comfort

PurposeThe ride vibration comfort of civil aircraft is one of the key factors affecting its market competitiveness, which is influenced by various vibration sources inside and outside the aircraft cabin. In order to enhance the vibration comfort in the cockpit, the nonlinear quasi-zero stiffness (QZS) vibration isolator with the horizontal spring sleeve mass is proposed.MethodsThe high-efficiency low-frequency isolation performance of the nonlinear QZS isolator system with the static equilibrium position slightly deviating from the ideal static is analyzed by the harmonic balance method, and the acceleration reductions of seat vertical vibration are evaluated based on the fourth order Runge-Kutta method. Considering the change of the pilot's mass, the parameter optimization algorithm based on the Kriging surrogate model is used to optimize the vertical spring stiffness, ideal mass, damping ratio, and horizontal spring compression of the QZS vibration isolator by using the sample updating criterion similar to the minimize surrogate model prediction.ResultsThe cockpit case research results indicate that after applying the optimized QZS isolator, the frequency-weighted root-mean-square (RMS) vertical acceleration of the aviation seat can be reduced by at least 83.03% for the pilot mass ranging from 49.5 to 94.4 kg. Namely, the frequency-weighted RMS acceleration decreases from 1.856 m/s2 to below 0.315 m/s2, meeting the not uncomfortable level in the International Standard ISO 2631-1.ConclusionsThe optimized QZS isolator can significantly reduce the frequency-weighted RMS acceleration of the seat and has important reference significance for the vibration comfort design of aircraft.