基于正弦基础激励的航天器结构模型修正方法

正弦振动试验是航天器系统级和单机产品需要开展的常规试验,充分利用工程中积累的正弦试验数据进行结构模型修正具有重要的工程意义。文章首先介绍了基础激励下结构模型修正方法,通过矩阵分块、待修正参数归一化、参与修正的频率点选择等步骤,推导出基于基础激励的模型修正公式;然后对国际通用算例GARTEUR桁架结构的有限元模型进行修正,分析修正后模型在修正频段内和修正频段外计算所得模态频率,验证修正后模型对模态频率的复现和预示能力,通过对比试验模型、分析模型和修正后模型中4个典型节点的响应曲线,检验修正后模型精度。结果表明:修正后模型的模态频率和响应曲线均与试验模型趋于一致,证实了该修正方法对GARTEUR结构修正的有效性。     

考虑重力的风机叶片水平加载测试方法

在风电叶片三维有限元参数模型中引入了重力产生的附加载荷,仿真计算了风电叶片水平加载方式的静载荷测试中附加载荷产生的水平方向的耦合位移,分析了耦合位移对测试过程中理论计算结果的影响;由于重力的叠加效应,测试中某些截面实际施加的等效载荷可能远超叶片设计的目标测试载荷,建议联合有限元分析,优化叶片安装角度和加载力方向的方法,降低叶片局部截面实际施加等效载荷的过载峰值。     

2. 5D 衍生结构SiO2 f / SiO2 复合材料的经向力学性能

以几种不同的2.5D衍生结构织物为增强体,制备了法向增强、经向增强及经法向增强2.5D Si O2f/Si O2复合材料,比较了上述材料与现有2.5D Si O2f/Si O2复合材料的经向力学性能,并研究了经法向增强2.5D结构复合材料中增强纱比例、纤维体积分数与材料性能之间的关系,对织物结构进行了优化。结果表明,经法向增强2.5D Si O2f/Si O2复合材料的经向力学性能较现有2.5D复合材料有显著提高,该材料在较低密度下(1.6 g/cm3),经向拉伸强度与现有材料(1.65 g/cm3)持平,且经向压缩强度接近现有材料的4.3倍。     

三维数模随动下的机翼结构重量优化

目前,基于快速建模下的重量重心估算系统得到了快速发展。为了进一步提高结构重量估算精度,研究了如何在重量重心快速分析(WCGA)系统环境中构建优化模块。以机翼结构重量优化为例,提出优化流程,对优化模块功能进行分解,给出模型简化要求。以A320飞机机翼为例,对梁和长桁进行优化,结果显示,经过优化,有效减轻了结构重量,且相比于传统的减重优化设计方法,极大提高了计算效率。     

水系统装置扬程的计算及泵的选型分析

为了提高水系统中水泵的实际运行效率和扬程利用率,降低发动机试验成本,减少能量浪费,以某型发动机台架试验水系统为研究对象,综合考虑了装置静扬程、管路的各种局部损失和沿程损失开展装置扬程的计算。同时根据水系统所需的装置扬程、流量及其变化规律,从泵的参数及其特性曲线入手,进行泵的选型分析,确定合适的泵的类型、台数及连接方式。通过水系统装置扬程的计算和泵的选型分析,结合泵带来的能效利用、工程投入和运行费用等因素,可在满足发动机试验需要的同时实现经济利益最大化,为今后类似水系统工程的设计提供借鉴和指导。     

反舰导弹换装发动机鉴定飞行试验方案设计

反舰导弹飞行试验的一项重要工作是检验发动机的工作性能及其他设备的匹配等。基于贝叶斯理论,利用数据综合技术设计反舰导弹换装发动机鉴定飞行试验方案,提出了小样本情况下弹上设备的鉴定方法,可为其他弹上设备鉴定提供重要参考。     

改进层次聚类法在复合材料敲击检测中的应用

伴随复合材料的迅速发展,其在航空航天方面的应用也日益普遍,但因复合材料的各向异性,在制造过程中会导致某些缺陷的产生。敲击检测作为一种实时原位的无损检测,在复合材料的检测中效果明显。由于敲击检测尚未找到合理的数据处理方法,所以其应用范围受到限制。从解决敲击检测数据处理方法的角度出发,提出将改进层次聚类法应用于敲击检测中,并在应用实例环节对该方法进行了应用,通过实验结果对比,表明改进层次聚类方法可以解决敲击检测数据处理的问题。     

大型客机一体化试飞改装设计方法研究

研究了大型客机试飞改装的要求和特点,提出了一体化试飞改装的设计方法,结合其在型号研制过程中的具体应用情况,具体阐述了一体化改装设计的方法及关键技术点。     

The Seed Population for Energetic Particles Accelerated by CME-Driven Shocks

Understanding properties of solar energetic particle (SEP) events associated with coronal mass ejections has been identified as a key problem in solar-terrestrial physics. Although recent CME shock acceleration models are highly promising, detailed agreement between theoretical predictions and observations has remained elusive. Recent observations from ACE have shown substantial enrichments in the abundances of ³He and He⁺ ions which are extremely rare in the thermal solar wind plasma. Consequently, these ions act as tracers of their source material, i.e., ³He ions are flare suprathermals and He⁺ ions are interstellar pickup ions. The average heavy ion composition also exhibits unsystematic differences when compared with the solar wind values, but correlates significantly with the ambient suprathermal material abundances. Taken together these results provide compelling evidence that CME-driven shocks draw their source material from the ubiquitous but largely unexplored suprathermal tail rather than from the more abundant solar wind peak. However, the suprathermal energy regime has many more contributors and exhibits much larger variability than the solar wind, and as such needs to be investigated more thoroughly. Answers to fundamental new questions regarding the preferred injection of the suprathermal ions, the spatial and temporal dependence of the various sources, and the causes of their variability and their effects on the SEP properties are needed to improve agreement between the simulations and observations.     

Two years of INTEGRAL result on X-ray binaries

INTEGRAL is the ESA lead International Gamma-Ray Astrophysical Laboratory, successfully launched the 17th October 2002 from Baikonur with a Proton vehicle. In view of the high sensitivity of the two γ-ray instruments IBIS and SPI and their capability to provide at the same time image, spectra and time profiles of all the sources in their wide field of view, a key project was approved as “Core Programme” to obtain deep observations of the Galactic Centre (GCDE) and to exploit regular scan of the whole Galaxy Plane since the beginning of the mission. This paper will briefly review the main astrophysical results obtained in the field of high energy Galactic sources with the INTEGRAL/IBIS γ-ray Imager onboard INTEGRAL, and make a comparison with the previous scenario depicted by the BeppoSAX and RXTE results.