A QUASI-ZERO STIFFNESS VIBRATION ISOLATOR BASED ON HYBRID BISTABLE COMPOSITE LAMINATE

A quasi-zero stiffness (QZS) vibration isolator has zero stiffness at its equilibrium position, and is efficient in isolating the low amplitude micro vibrations. Therefore, the QZS vibration isolators have excellent potential in applying on the micro vibration isolation of space structures, e.g. satellite structures. Normally, a QZS vibration isolator composes of a positive stiffness element and a negative stiffness element. In many concepts of QZS vibration isolators, the negative stiffness elements are inefficient in weight and volume, because they are normally combined by several components, and external restrains or forces are needed to stress certain components. As a result, the volume and weight of the QZS vibration isolators are unacceptable in some applications, such as space technology and aviation technology. In order to improve the weight and volume of QZS vibration isolators, in this study a novel QZS vibration isolator is put forward by applying the bistable composite laminates as negative stiffness element. The system of this QZS vibration isolator is greatly simplified because of the inherent negative stiffness of bistable laminates. The principle of this novel QZS vibration isolator is illustrated, and the performance of which is analyzed by finite element method. A prototype of the novel QZS vibration isolator is fabricated and is tested in experiment. Experimental results indicate that the acceleration transmission rate of the proposed QZS vibration isolator is much improved comparing with a linear spring isolator. Nevertheless, the tested results of the isolator are not as good as predicted via the finite element analysis. The in practice performance of the proposed QZS vibration isolator is analyzed and discussed. Finite element analysis illustrates that both manufacturing error and assembly error have significant negative influence on the practical performance of the proposed QZS vibration isolator, and the robustness of the isolator should be improved in the future work.