Re-entry Spacecraft Support Structure Dynamic Characteristics

Vibration isolation support structure is the mechanical interface between electronic equipment and transportation equipment. And it is the key component to secure the normal operation of electronic equipment under complex work environment. In actual engineering, electronic equipment always bears various mechanical forces. Vibration and shock of transportation equipment is the greatest risk factor to the electronic equipment. The malfunction caused by vibration is about 80%. The main destruct form of the electronic equipment is abnormal vibration acceleration which beyond the limit under a vibration frequency.The research status of structural dynamics optimal design of the support structure is discussed in this paper. Based on the geometry structural design of the support structure,FEM,modal analysis,random vibration theory and structural optimization theory, the dynamic model of the support structure system is established. It is solved through the Lanczos modal algorithm. The dynamic characteristic of the support structure is analyzed. Considering random vibration incentives, the random response of the dynamic model of the support structure system is analyzed by vibration mode superposition. From the simulation result, we can find that the random response results accord with the actual situation and the rationality of the dynamic model is verified.Based on the analysis of the inherent characteristics and the random response result, the model of optimization for the support was established by the theory of intensity equation. Under the condition of structural safety, optimization design with shape and size was put in practice based on combination theories of optimization and reliability-based design. The purpose of the optimization is to reduce weight,to improve the stiffness and to reduce the random vibration amplitude. It shows that the weight of the support structure is reduced by 23.6%, meanwhile the acceleration random response RMS of Key component is reduced and the structure of the support is more reasonable. The method has the comparative theory and project practical value.