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中文核心期刊

航天器噪声试验中结构振动响应预示方法研究

METHOD STUDY ON RESPONSE PREDICTION OF STRUCTURAL VIBRATIONS IN SPACECRAFT ACOUSTIC TESTS

  • 摘要: 航天器在随运载火箭发射过程中要承受严酷的噪声环境,需通过噪声试验来检验航天器承受噪声环境并能正常工作的能力.航天器噪声试验中结构振动的响应特性是结构强度设计应该考虑的因素之一,更是制定器上组件随机振动试验条件的重要依据,因此有必要在航天器研制初期对噪声载荷作用下的结构振动进行响应预示.文章应用商用有限元分析软件MSC.Patran和MSC.Nastran建立了某型号航天器结构舱板的有限元模型,将噪声载荷声压谱转换为脉动压力功率谱密度,进而采用模态法分析结构在噪声载荷作用下的随机振动响应,并将仿真预示结果与试验结果进行对比研究,在仿真分析中考虑阻尼参数模型和流场附加质量效应等因素的影响;通过研究表明:采用阻尼比随频率提高而减小的经验阻尼参数模型可以较好地反映中高频响应特性、得到较为准确的总均方根响应分析结果,进一步采用虚拟质量法考虑流场附加质量效应可以得到较为准确的功率谱密度响应分析结果.文章提出的仿真分析方法建模简便、计算成本低,适用于在航天器研制初期对航天器噪声试验中的结构振动进行响应预示.

     

    Abstract: Spacecraft suffer severe acoustic environments in the course of launching along with launch vehicles. Acoustic tests should be done to check up whether the spacecraft work well while suffering acoustic environments. Response properties of structural vibrations during acoustic tests for spacecraft should be considered in the structural strength design. Moreover, they are important foundations for specifying the random vibration test conditions of the spacecraft equipment mounted on the structural boards. Therefore, it is necessary to predict the structural responses due to acoustic loads in the preliminary stage of spacecraft development. In this paper, a finite element model of a spacecraft structure is built using the commercial finite element analysis software MSC.Patran and MSC.Nastran. The sound pressure level spectrum of acoustic loads is transformed to the power spectrum density of fluctuating pressure. And then, the random vibration responses of the spacecraft structure under the acoustic loads are analyzed using the modal method. The simulation results are compared with the acoustic test results. In the simulation analysis, the effects of the damping ratio model and the fluid added mass are studied. The research shows that: using an empirical damping ratio model that the damping ratio decreases with the rising of the frequency can do a better response prediction for the medium-high frequency properties as well as for the total root mean square results; further using the virtual mass method to consider the fluid added mass effect can do a better response prediction for the power spectrum density results. The proposed simulation method in the article is convenient for modeling and efficient for computation, which is appropriate for the response prediction of structural vibrations in spacecraft acoustic tests in the preliminary stage of spacecraft development.

     

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