星箭结构的动力学建模方法与声—固耦合动响应分析研究

发布时间：2018-05-14 23:42

本文选题：星箭结构 + 蜂窝夹芯板　；参考：《东南大学》2016年硕士论文

【摘要】：航天器在发射和服役时面临复杂的振动和噪声动力学环境,而准确的动力学声振环境预示是指导航天器总体设计、结构设计、以及地面试验方案与试验条件制定的重要依据。本文以星箭结构为研究对象,重点开展三方面的研究工作：研究星箭结构的动力学建模方法,建立能较为准确反映结构动力学特性的模型；研究星箭结构的声-固耦合动响应预示方法,揭示声振环境下的动响应规律；研究整流罩结构的声传递特性,为星箭结构的优化设计以及减振降噪设计提供指导。准确的动力学模型是后续声-固耦合响应预示的基础。首先开展星箭结构中典型的包带连接的等效建模方法研究,推导包带连接结构在不同预紧力下的轴向刚度,并探讨包带连接结构轴向刚度对星箭结构固有特性的影响。然后针对运载火箭整流罩中常用的蜂窝夹芯结构,分别采用等效板理论和三明治夹芯板理论进行等效建模,分析蜂窝夹芯板和等效板在平面波作用下考虑声-固耦合时的传声损失和声辐射响应,研究等效模型在动力学分析时的精度与效率,从而探索一种适用于大型航天器结构声学分析以及动响应分析的等效建模方法。准确的声-固耦合动响应预示是后续动强度评估的基础。基于FEM-BEM法分别进行随机振动激励、噪声激励以及随机振动／噪声联合作用等复合激励下星箭结构的声-固耦合动响应预示研究。给出不同激励下的声振响应规律,探讨不同激励成分对结构动响应的贡献,并重点研究耦合效应以及包带连接刚度对结构固有特性和动响应的影响。准确的星箭力学环境是进行星箭结构动响应预示和声学优化设计的基础。针对运载火箭整流罩典型薄壁圆柱壳结构,基于Love理论给出薄壁圆柱壳的声传递表达式,分析柱状声波作用下的声传递损失以及声辐射响应,探讨整流罩壁厚、肋骨数目以及飞行角度对整流罩传声损失以及声辐射的影响。基于声传递向量法进行整流罩结构的声学板块贡献量分析,重点分析场点处声压响应在各频带内的分布,以及在特定频率处结构各板块的贡献量。此研究对结构的优化设计以及减振降噪设计具有一定的指导作用。
[Abstract]:Spacecraft are faced with complex dynamic environment of vibration and noise during launch and service. Accurate prediction of dynamic acoustic environment is an important basis to guide spacecraft overall design, structural design, ground test scheme and test conditions. In this paper, the star-arrow structure is taken as the research object, and the research work is focused on three aspects: the dynamic modeling method of the star-arrow structure is studied, and the model which can accurately reflect the dynamic characteristics of the structure is established; The prediction method of acousto-solid coupling dynamic response of star-arrow structure is studied to reveal the law of dynamic response in acousto-vibration environment, and the acoustic transfer characteristics of fairing structure are studied to provide guidance for the optimization design of star-arrow structure and the design of vibration and noise reduction. Accurate dynamic model is the basis of prediction of acousto-solid coupling response. In this paper, the equivalent modeling method of the typical envelope connection in star-arrow structure is studied, the axial stiffness of the envelope connection structure under different pretightening forces is deduced, and the influence of the axial stiffness on the inherent characteristics of the star-arrow structure is discussed. Then the equivalent plate theory and sandwich theory are used to model the honeycomb sandwich core structure commonly used in the fairing of launch vehicle. The sound transmission loss and acoustic radiation response of honeycomb sandwich panels and equivalent plates considering acousto-solid coupling under plane wave are analyzed. The accuracy and efficiency of the equivalent model in dynamic analysis are studied. Thus an equivalent modeling method suitable for structural acoustic analysis and dynamic response analysis of large spacecraft is explored. Accurate prediction of acousto-solid coupling dynamic response is the basis of subsequent dynamic strength evaluation. Based on the FEM-BEM method, the prediction of acousto-solid coupling dynamic responses of star-arrow structures under random vibration excitation, noise excitation and combined random vibration / noise excitation is studied respectively. In this paper, the law of acoustic and vibration response under different excitations is given, and the contribution of different excitation components to the dynamic response of the structure is discussed. The coupling effect and the influence of the coupling stiffness on the natural characteristics and dynamic response of the structure are studied. Accurate mechanical environment of star-arrow is the basis of prediction of dynamic response of star-arrow structure and acoustical optimization design. Aiming at the typical thin-walled cylindrical shell structure of the fairing of launch vehicle, the expression of acoustic transfer of thin-walled cylindrical shell is given based on Love theory. The sound transfer loss and acoustic radiation response under the action of cylindrical acoustic wave are analyzed, and the wall thickness of the fairing is discussed. The influence of the number of ribs and the flight angle on the sound transmission loss and sound radiation of the fairing. Based on the acoustic transfer vector method, the acoustic plate contribution of the fairing structure is analyzed, and the distribution of the acoustic pressure response at the field point in each frequency band and the contribution of each plate in the structure at a specific frequency are analyzed. This research has certain guiding function to the optimization design of structure and the design of vibration and noise reduction.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V414

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