结构局部刚度变化对小卫星动特性影响

首先针对模块式小卫星动特性进行灵敏度理论分析，分析目标是寻找提高结构动特性的局部位置和参数。然后基于有限元法分析改变局部刚度对结构动特性的影响。小卫星结构动特性分析计算的主要问题是建立计算成本可控的有限元模型，本文详细讨论了小卫星有限元模型建模方法和简化途径，并通过7个算例考察改变模块底板局部刚度、改变适配器支撑刚度、模块问设置弹簧模拟阻尼器等对小卫星结构动特性的影响。灵敏度分析和计算表明，影响动特性的主要因素是模块盒底板刚度和星箭适配器的支撑刚度；增加模块局部刚度以及适配器支撑刚度可以屏蔽星体摆动和包带联结部位的某些频率，同时可以减缓部分中间模块的振幅；在部分模块间设置弹簧可以模拟阻尼器或减振器的效果。另一方面，降低适配器刚度可以增加隔振作用。因而优化模块刚度分布和支撑刚度分布是改进动力学性能的有效途径。本文分析为模块式小卫星动力学修改以及多功能结构设计和主动振动设计提供依据。

The effect of local stiffness of structure on dynamic characteristics of small satellites

This paper presents sensitive analysis of structure of small satellite based on sensitive analysis theory and modal analysis based on finite element method aiming at providing ways to improve the dynamic performance of small satellites by changing the local stiffness of structure of small satellites.The key problem to model a whole small satellite is to build an effective finite element model under controllable computing cost.This paper discusses the process to build a finite element model of the structure of whole small satellite.On the other hand,the goal of sensitive analysis is to locate the very positions and the parameters that have effect on the dynamic characteristics of the structure.Based on sensitive analysis,modal analysis and other dynamic response analyses,it can be concluded that the main factors contribute to the dynamic characteristic of the structure is the stiffness of the bottom of the box and supporting rigidity of the adapter.The sensitive analysis and modal analysis simulation prove that increasing the stiffness of the bottoms of boxes and increasing the support rigidity of adapter will shield certain frequencies and decease the amplitudes of certain boxes.And also,to set springs between certain adjacent boxes can simulate the effect of dampers or vibroshocks.Another way to damp the vibration of satellite is to isolate vibration by lower the rigidity of the adapter.