Vibration Isolation Mechanism Based On Bi-stable Composite Laminates

With the development of the spacecraft towards high-resolution,the micro-vibration gains more and more attentions for its negative effect on the performance of imaging payload.Micro-vibration produced by the on board equipment in spacecraft(such as control momentum gyros,reaction wheel assemblies,solar panel deployment actuators and other motion devices)will seriously degrade the image quality of the spacecraft.Micro-vibration has the characteristics of low amplitude,a wide frequency range.To ensure spacecraft reliability,the use of passive vibration equipment for spacecraft micro-vibration control is still an important way.Since a linear vibration isolator can prove an effective isolation when the excitation frequencies are greater than 2?_n,where?_n is the natural frequency of the system,QZS(quasi-zero stiffness)isolator received widespread attention.Bi-stable composite laminates are laminated composites have two stable configurations,and are able to transform between stable configurations under external load.Bi-stable laminates show negative stiffness characteristics during configuration transition.The purpose of this study is to design a new type of QZS vibration isolator by using the cross-ply bi-stable laminate in parallel with linear spring.In this paper,a 17 parameter mechanics model of cross-ply bi-stable laminates is established.The relationship between the configuration prediction,bearing capacity,stiffness characteristics and fiber layer thickness of the cross-ply laminates were studied by using the theory and the finite element method.The effect of the thickness of the hybrid aluminum layer on the above properties was also studied.The potential application of laminates with critical thickness to spacecraft micro-vibration control was also studied.A new type of QZS vibration isolator was designed,established its theoretical method and studied its vibration isolation effect.The results show that the new type of vibration isolator designed in this paper can obviously reduced the natural frequency of the system and widen the vibration isolation frequency band compared with the linear vibration isolator.Finally,the principle prototype of the QZS isolator is fabricated and the feasibility of introducing the bi-stable laminate into the linear vibration isolation system to improve its vibration isolation performance.