针对商业航天快速响应火箭型号,要求飞行可靠性高、准备周期短及发射成本低等,本文提出基于三维网格模型的模态特性仿真分析方法,首先对箭体进行精细化建模,对各单机、管路等结构件进行简化处理,由于预紧力作用下的螺栓连接,应力呈现出较强局部特性,所以对舱段连接采用等效刚度建模的方法,最终选择各舱段主体结构材料杨氏模量和舱段连接刚度作为待修正参数,基于灵敏度分析技术,修正箭体动力学模型,并基于该模型对其他箭体模态特性进行高精度预示,助力飞行试验的成功.

本文首先建立了简单锥柱壳及其内部声场的声振耦合动力学分析模型,包括有限元模型和统计能量模型;然后结合混响场试验结果修正分析模型;最后通过湍流边界层经验模型施加激励,模拟飞行过程中的非定常气动环境,采用修正后的动力学分析模型开展声振耦合动力学分析,讨论锥柱壳结构响应及其内部声场响应情况,为后续开展减振降噪设计打下基础.

当前航天装备承制周期较短,概念设计能力需求增强,仿真迭代设计工作增多,故需要提高结构的快速有限元建模能力,传统型号研制中较多采用六面体实体单元建模,建模水平要求高,效率较低.本文首先利用MSC.Apex软件对复杂结构进行二阶四面体单元网格自动划分,并验证其建模有效性,可替代人工六面体建模;再介绍单元拼接建模,对某些结构进行二阶四面体和六面体网格拼接,通过模态频率和模态振型两个方面验证建模的工程实用性,该方式兼顾了四面体建模的快速性和六面体网格易于编辑的优点,具备较高的工程创新性,可推广使用.

推进剂贮箱内金属膜片通过变形、翻转将推进剂挤入输送管路,为姿轨控发动机工作提供燃料和氧化剂,实现飞行姿态控制、机动变轨等功能.金属膜片具有质量轻、高可靠性、高排放效率等诸多优点,被广泛应用于空间飞行器及导弹系统控制领域.本文总结了国内外关于空间飞行器推进系统贮箱金属膜片的研究现状,重点梳理了膜片的理论分析及仿真计算技术进展;针对膜片翻转失效问题,简要总结了膜片各技术参数对其变形翻转的影响,可为贮箱膜片后续研究提供一定参考;最后提出了现阶段贮箱膜片研究中亟待寻求技术创新突破的领域.

With the advantages of metal rubber materials in vibration damping,a vibration damping plan based on a metal-rubber vibration absorber was proposed to damp the vibration for the integrated instrument installation plate of a aerocraft.A mechanical model of the metal-rubber vibration absorber was established and the design and performance parameters of the metal damping pad structure were designed.Then the instrument installation plate designed with integrated vibration damping method was simulated.At last,a ground vibration experiment was designed to test the vibration of the instrument installation plate.The results show that the analysis results are in agreement with ground experiment ones basically,and the stiffness meets the design requirements.Furthermore,with the integrated vibration damping by the metal-rubber vibration absorber,the random vibration amplitudes of the measuring points on the plate has a remarkable energy attenuation above 300 Hz and the random response mean square root attenuation is no less than 56.5% below 300 Hz as comparing to the instrument installation plate with a rigid connection.