大展弦比机翼剖面刚度分析

通过对变截面悬臂梁在一端受载时,自由端的位移、转角和悬臂梁各剖面刚度之间关系的分析,推导出一种基于有限元模型的剖面刚度计算方法。针对某型飞机,对机翼结构进行适当简化,建立机翼主承力结构的有限元模型,采用所推导出的方法计算了机翼沿展向各剖面的刚度,其结果可为某型飞机机翼结构设计和气动弹性分析提供参考。     

一种应用于半闭环低刚度TVC伺服系统的力矩反馈控制方法

针对新型火箭发动机喷管刚度低、伺服系统呈半闭环结构导致的伺服系统谐振和快速性之间难以调和的问题,以上面级电动伺服系统为研究对象,对机构参数与系统性能之间的关系进行了仿真研究,提出了一种新的谐振抑制控制方法,引入力矩反馈使伺服机构具有力矩控制能力。仿真结果表明,提出的力矩反馈控制方法具有比陷波算法更优的谐振抑制能力,运算量并未增加,且涉及的参数均可通过测试得到,调试难度有所降低。     

剪切刚度对复合材料层合扁球壳非线性振动屈曲的影响

本文采用突变理论,建立了复合材料层合扁球壳非线性振动屈曲的突变模型,分析了剪切刚度对复合材料层合球壳非线性振动屈曲性态的影响。     

2.4m风洞大迎角机构结构设计与有限元分析

研制具有良好力学特性的大迎角机构,是解决先进、高机动飞行器武器大迎角气动力问题的关键技术之一.阐述了2.4m风洞大迎角机构结构形式,同时应用MSC/NASTRAN有限元软件,对其强度、刚度和动态特性进行了有限元分析,获得了大迎角机构在最大气动力载荷作用下的结构应力和变形,以及自由振动时的模态频率和模态振型.计算结果表明:大迎角机构本身结构强度、刚度富余;固有频率远离气流脉动频率,表明其具有较好的动态特性;该机构结构形式合理可靠.     

某减压阀静态特性分析

建立了某减压阀静态特性模型,并用实验验证了模型的正确性.通过仿真讨论了膜片有效面积、网芯不平衡面积和阀门总刚度对减压阀静态特性的影响.结果表明:阀门总刚度的影响较大,而膜片有效面积和阀芯不平衡面积的影响相对较小.     

外挂物、副翼操纵刚度对机翼颤振特性的影响

采用某型号机颤振风洞模型风洞试验的方法，研究了机翼外挂物重量、悬挂位置和不同的副翼操纵系统刚度对机翼颤振特性的影响。并对试验结果进行了分析。     

切削测力仪的杠杆—附加弹性元件设计方法

为解决目前应变式切削测力仪设计中普遍存在的刚度和灵敏度之间的矛盾,本文在对已有应变式切削测力仪特性进行分析的基础上,提出了切削测力仪的杠杆—附加弹性元件设计方法的原理,并讨论了应用该方法设计时有关的若干问题和该方法在解决切削测力仪刚度与灵敏度之间矛盾方面所可能的贡献。理论分析的结果表明,该方法能有效地解决测力仪的刚度和灵敏度的矛盾,为大幅度提高切削测力仪的综合精度指标开创了新的途径。最后,介绍了笔者采用杠杆附加弹性元件方法研制的新型切削测力仪。实测结果表明,该测力仪同时具有高刚度和高灵敏度,其刚度与灵敏度乘积指标较现有同类测力仪提高了近一个数量级。     

The IGY and beyond: A brief history of ground-based cosmic-ray detectors

The state of art of ground-based cosmic-ray research from its discovery to present is reviewed. After discovery of cosmic rays by Hess in 1912, the nature of the primary and secondary radiation was established from recordings by a variety of instruments, sensitive to various components of cosmic rays and operated at different latitudes, longitudes and altitudes, including instruments carried by balloons. The IGY formalized international co-operation and coordinated study of cosmic rays, which is vital for meaningful interpretation of cosmic-ray data. Data collected at different geographic locations require an effective cutoff rigidity as a data ordering parameter. This parameter is obtained from tracing trajectories of primary cosmic rays in the Earth’s magnetic field. After 50 years the world’s neutron monitor network remains still the backbone for studying intensity variations of primary cosmic rays in the rigidity ranges between 1 and 15 GV, associated with transport and with transient events. Also the penetrating muon and neutrino components of secondary cosmic rays have a long history of recording and fundamental problem investigations. Valuable data about composition and spectrum of primary cosmic rays in ever increasing high-energy regions have been obtained during the years of investigations with various configurations and types of extensive air shower detectors. The culture of personal involvement of the physicist in carrying out experiments and data acquisition characterized the continued vitality of cosmic-ray investigations ranging from its atmospheric, geomagnetic and heliospheric transport through to its solar and astrophysical origins.     

Recent progress in flexible supporting technology for aerospace thin-walled parts: A review

Thin-walled parts are widely used in the aerospace industry owing to their light weight and high specific strength. However, due to the low rigidity of thin-walled parts, elastic deformation and chatter easily occur, which seriously affect the machining accuracy and workpiece surface quality. To solve this problem, several supporting technologies have been reported in recent years. This paper reviews the recent research progress of flexible supporting technologies in the aerospace field by class...     

On the possibility to check the magnetosphere’s model by CR: The strong geomagnetic storm in November 2003

We report on a study of cosmic ray cutoff rigidity variations during the strong geomagnetic storm of 18–24 November 2003. We employed the most recent Tsyganenko magnetospheric model to represent the very strong disturbed Magnetosphere. We used this magnetic field for the cosmic ray trajectory calculations to determine the geomagnetic cutoff rigidity throughout this period of severe geomagnetic disturbance. We determine the cutoff rigidity changes during this period by two methods, by trajectory calculations and by the spectrographic global survey method. The values of the change of cutoff rigidities obtained by two different methods are correlated with the D_st and interplanetary magnetic field and plasma parameters and result in correlation coefficients in the range 0.63–0.84 for the various cosmic ray stations. The result of this study indicates that the most significant contributions to the cutoff rigidity changes are due to D_st variation although the influence of solar wind density and B_z and B_y components of IMF variations is significant.