智能结构及其在振动主动控制中的应用

针对航天挠性结构的振动控制 ,介绍了智能结构的提出、概念、诞生原因以及作为智能结构中的传感和驱动元件的各种智能材料的特点 ,着重阐述了梁、板和壳结构的振动控制中应用的压电材料的国内外研究状况和采用的控制策略 ,并对智能结构在主动振动控制应用研究的问题进行了评述 ,如传感器 /驱动器的优化配置问题及准则 ,柔性结构的控制溢出问题及抑制方法。最后针对航天器的结构振动控制 ,展望了今后的研究与发展方向     

L型复合材料机械连接接头承载能力与失效行为研究

L型复合材料连接结构已应用于运载火箭结构的端框设计,但目前对于该结构的承载能力和破坏模式缺乏研究。将典型的L型连接端框简化为无弧度的平直L型接头片段,通过单向对拉试验,对6 mm和8 mm两种厚度L型机械连接接头的承载能力和破坏模式进行了研究。由承载能力试验结果表明:L型接头在拉力作用下呈现出明显的A、B、C三个阶段,其中A阶段的拉力最大值可作为该类接头结构的极限承载能力。采用有限元方法分析接头的破坏模式,仿真与试验结果的误差为2.5%,取得了较好的一致性。由数值分析表明:拉力作用下L型接头的承载能力主要取决于螺栓压紧区附近和直角拐角区域的层间强度和基体强度;在原铺层信息基础上增加0°层数和降低90°层数,对接头承载能力提升效果不明显。研究结果可为L型复合材料连接结构的设计提供参考。     

用于薄结构中电磁场计算的三维高精度壳体矢量单元

提出了一种适用于薄结构中电磁场计算的通用三维高精度壳体矢量单元。该类壳体单元在薄结构厚度方向对场矢量采用一阶矢量插值，而在薄结构面方向采用二阶矢量插值，能够很容易地应用于平面和曲面薄结构问题的建模与求解。文中应用该壳体矢量单元与2阶六面体矢量单元对比做了两个算例，结果表明：使用该壳体矢量单元建模计算薄层结构不仅可以达到高的计算精度，而且能节约未知量数目一半以上，节约计算时间达80％以上。     

飞行器结构智能化研究及其发展趋势

智能化是飞行器结构发展的重要趋势，文中介绍了飞行器结构的智能化需求及其发展状况。阐述了飞行器的典型结构健康监测方法及其技术特征，讨论了飞行器主动变形结构的实现方法与途径，结合国内外研究情况，指出了飞行器结构智能化的可实现前景。     

Possible role of electrostatic potential in formation of sharp boundaries of small-scale and middle-scale solar wind structures

Sharp boundaries of small-scale and middle-scale structures of the solar wind are an essential part of a turbulized solar wind. Such boundaries are observed near the Earth’s orbit as sharp and large-amplitude changes of parameters (in particular, ion density) of the solar wind. In this paper, the observed phenomena are briefly described, and an account of their basic properties and specific features is given. Using the kinetic approach, a possible theoretical mechanism is suggested in order to explain some peculiarities in the formation of these structures.     

载人航天器结构工艺瓶颈及对策

文章对我国载人航天器工艺需求进行了分析,对载人航天器现存的薄壁结构残余应力控制与消除技术、载人密封结构高可靠低应力焊接技术、碳纤维复合材料应用技术等工艺瓶颈进行了研究,并针对工艺瓶颈提出了解决对策。     

光子晶体热控结构防护性能研究

光子晶体在红外波段同时具有高反射率和高辐射率,可作为高超声速飞行器的防热材料。文章利用FLUENT软件和辐射模型中的离散坐标算法对有/无光子晶体防热层结构进行了气动加热数值模拟计算,得到了在不同热流密度条件下基体的温度分布;通过计算结果的对比发现,采用光子晶体防热层结构使基体温度下降约360～515 K,具有良好的热控性能。光子晶体是一种具有广阔应用前景的热防护材料,作为高超声速飞行器的防热层结构的可行性与有效性还有待深入研究。     

轻质复合材料夹芯结构设计及力学性能最新进展

从设计、制备和力学性能方面对轻质复合材料夹芯结构的最新研究成果进行总结，包括复合材料点阵夹芯结构、褶皱夹芯结构以及蜂窝夹芯结构对应的拓扑构型设计和制备工艺，重点从力学性能的理论预报、力学性能实验表征和失效模式分析等角度评述了性能改进的最新研究。通过对轻质复合材料夹芯结构最新研究进展的总结与分析，展望了点阵夹芯结构、褶皱夹芯结构和蜂窝夹芯结构的发展趋势及可能应用领域。     

Initial performance assessment of hybrid inflatable structures

Inflatable technology for space applications is under continual development and advances in high strength fibers and rigidizable materials have pushed the limitations of these structures. This has lead to their application in deploying large-aperture antennas, reflectors and solar sails. However, many significant advantages can be achieved by combining inflatable structures with structural stiffeners such as tape springs. These advantages include control of the deployment path of the structure while it is inflating (a past weakness of inflatable structure designs), an increased stiffness of the structure once deployed and a reduction in the required inflation volume. Such structures have been previously constructed at the Jet Propulsion Laboratory focusing on large scale booms. However, due to the high efficiency of these designs they are also appealing to small satellite systems.This article outlines ongoing research work performed at the University of Southampton into the field of small satellite hybrid inflatable structures. Inflatable booms have been constructed and combined with tape spring reinforcements to create simple hybrid structures. These structures have been subjected to bending tests and compared directly to an equivalent inflatable tube without tape spring reinforcement. This enables the stiffness benefits to be determined with respect to the added mass of the tape springs. The paper presents these results, which leads to an initial performance assessment of these structures.     

空间结构展开与刚化

空间展开结构具有能构建大型结构、轻质而且成本低廉的特点。在航天器中呈折叠状的空间结构在空间充气展开后,要呈刚化,使其不因温度变化而引起变形并且不会因空间碎片或流星体的碰撞而被损坏。文中提出了展开前的折叠方法和包装效率评估方法。提出了两种刚化薄膜,在储存状态下易于折叠并能保持其所有的性能。一种采用单层薄膜浸渍长储存寿命树脂基的三轴编织纤维,另一种采用宽广温度范围长储存寿命的交互编织纤维刚性薄膜。     

Evaluation of membrane structure designs using boundary web cables for uniform tensioning

A design challenge in large membrane space structures is to apply pretension as uniformly as possible throughout the membrane, without increasing structural mass and volume. The present paper begins with a brief review of existing designs of membranes surrounded by catenary cables and shear compliant borders. The paper then introduces weblike cables that surround the membrane, and analyzes the consequent reduction in mass and volume. In addition, a series of quasi-static finite element analyses demonstrates the attenuation of wrinkles by the web cables when support points are perturbed. The paper concludes that the proposed design preserves a biaxially prestressed membrane even in disturbed conditions, with a minimal suspension-cable mass and volume.     

Family of deployable/retractable structures for space application

New trends in the frame of space applications lead to the necessity of using deployable/retractable structures, working either as beams (with payloads all along their length) or masts (loaded at their tip). SENER—under ESA/ESTEC and Spanish Space Program contracts—are developing a family of structures with deployment and retraction capabilities (LTS, SENERMAST, CTM) so as to cover all ranges of potential necessities in the space community (antennas, experiment support, solar arrays, heat rejection systems …). This paper consists of a summary of the performances and range of applications of LTS, SENERMAST and CTM, and pays special attention to the large truss structure (LTS) development and verification.     

浅析振动试验中结构非线性引发的现象

火箭、卫星、导弹等航天产品普遍存在着结构非线性。在这些产品的振动试验中常常出现固有频率漂移、谐波响应等现象,并且会带来部件间固有频率耦合、碰撞振动、振动试验控制超差等问题。本文章从结构非线性入手定性的地分析了引发这些现象的原因,并介绍一些解决措施,为振动试验中类似问题的分析和解决提供参考。     

Dynamic qualification of large space structures by means of modal coupling techniques

In this paper some problems are described which are expected to arise during dynamic qualification of future large space structures. It is shown that the methods applied today, are no longer sufficient. As conclusion, the concept of a qualification procedure is proposed, which considers the phase of launching, as well as the phase of mission in orbit.     

Dynamics and control of variable-geometry truss structures

Variable-geometry truss structures are likely to be used extensively in the future for in-orbit space construction. This paper considers dynamics formulation and vibration control of such structures. The truss system is modelled as a collection of sub-structures consisting of truss booms, prismatic actuator elements, and in some cases a manipulator at the end. Each truss boom is treated as a separate ‘link’ and its flexibility is modelled using the finite element method. Equations of motion for individual sub-structures are obtained which are then assembled. The non-working constraint forces are eliminated to obtain the equations governing the constrained dynamics of the entire system. For vibration control, the singular perturbation method is employed to construct two reduced-order models, for quasi-static motion and for modal co-ordinates, respectively. Computed torque with PD control is applied to maintain the quasi-static motion, while an optimal LQR method is used for vibration control. Typical simulation results are presented for the planar case.     

空间结构展开与刚化

空间展开结构具有能构建大型结构、轻质而且成本低廉的特点。在航天器中呈折叠状的空间结构在空间充气展开后，要呈刚化，使其不因温度变化而引起变形并且不会因空间碎片或流星体的碰撞而被损坏。文中提出了展开前的折叠方法和包装效率评估方法。提出了两种刚化薄膜，在储存状态下易于折叠并能保持其所有的性能。一种采用单层薄膜浸渍长储存寿命树脂基的三轴编织纤维，另一种采用宽广温度范围长储存寿命的交互编织纤维刚性薄膜。     

巡视探测器悬架机构综述

悬架机构是巡视探测器移动系统的重要组成部分，其性能直接影响着巡视探测器的通过性能、越障能力和稳定性等。文章分析了目前应用于巡视探测器的各种悬架，分别为杠杆导向的扭力式独立悬架、摇臂转向架悬架、五轮五点接触悬吊式悬架、平行架一叉形架悬架、三体柔性悬架、ExoMars巡视探测器悬架系列（RCL-C、RCL-E、CRAB和Double Spring）、正反四边形悬架等。在分析的基础上总结了巡视探测器悬架机构的发展趋势，同时为我国月面巡视探测器移动部分悬架机构的选择提出了建议。     

混凝土结构温度裂缝成因及控制措施

本文简单分析了混凝土结构温度裂缝产生的机理，根据实际情况提出了结构设计和施工时温度裂缝的控制措施。     

考虑平整性要求的板壳自适应结构静变形控制

基于四节点压电复合材料层合板单元和相应有限分析方法，利用结构位移对电压的灵敏度，对以压电材料为作动器的板壳自适应结构，进行了考虑平整性要求的静力变形控制。根据控制目标和约束限制，由数学规划问题确定结构承载时作动器所需的控制电压，最后以数值算例给出了仿真结果，以验证所提出方法的有效性。     

流量调节器研制中的主要问题及结构改进

介绍了一种用于液氧／煤油发动机的流量调节器的结构、原理。在调节器研制中出现的主要问题有滑阀卡滞、主级工况的负载特性存在负差率、转级活塞不能复位等。根据调节器的工作条件,运用静力学原理,分析了产生的原因,提出了改进方法,并进行了试验验证。试验结果表明：结构改进后的调节器工作可靠性得到了明显提高。