An Archetypal Vibration Isolator with Quasi-zero Stiffness in Multiple Directions

Abstract To avoid the failure under longitudinal, shear, and mixed wave from earthquake, an archetypal vibration isolator based on a smooth discontinuous (SD) oscillator is proposed. This model comprises lumped mass mounted by vertical spring horizontal elastic continuum, which separately provides positive negative stiffness forming stable quasi-zero (SQZS) in all directions. The equation of motion formulated employing Lagrange equation, SQZS condition obtained optimizing geometrical parameters system. analysis shows that system admits remarkable performance isolation with low resonant frequency large stroke interval. results also demonstrate has improved aseismic behaviour complex excitation seismic significantly.