双向阶梯式矩形板的自由振动

本文采用Reisaner—Mindlin一阶剪切变形板理论，得出n级双向阶梯式矩形板自由振动系统的总位能。通过Raylcigh-Ritz法，采用粱函数作为各种边界条件下阶梯式板的位移函数，求得阶梯式板的自振频率。     

Flutter analysis of hybrid metal-composite low aspect ratio trapezoidal wings in supersonic flow

An effective 3D supersonic Mach box approach in combination with non-classical hybrid metal-composite plate theory has been used to investigate flutter boundaries of trapezoidal low aspect ratio wings. The wing structure is composed of two main components including alu-minum material (in-board section) and laminated composite material (out-board section). A global Ritz method is used with simple polynomials being employed as the trial functions. The most important objective of the present research is to study the effect of composite to metal proportion of hybrid wing structure on flutter boundaries in low supersonic regime. In addition, the effect of some important geometrical parameters such as sweep angle, taper ratio and aspect ratio on flutter boundaries were studied. The results obtained by present approach for special cases like pure metal-lic wings and results for high supersonic regime based on piston theory show a good agreement with those obtained by other investigators.     

轻质铝箔V-型皱褶构型板雷达散射性能研究

 设计并制作了14个不同几何特征参数的V-型铝箔皱褶构型板。运用电磁数值仿真软件对它们的雷达散射截面(RCS)进行了计算,分析了V-型皱褶板几何特征参数对雷达散射性能的影响。同时,用LFY铝箔制作了14个不同几何特征参数的皱褶构型板,并对它们进行了RCS实验测试。通过对比分析发现,数值计算结果和实验测试结果基本吻合。结果显示,在一定的结构参数下,轻质铝箔皱褶板的RCS比同样平面几何尺寸的平板小,有的甚至降低20 dBsm。铝箔皱褶板成型工艺简单,结构重量轻,价格低廉,可用于包敷飞行器内部有较大RCS的大尺寸构件,从而降低整个飞行器的RCS。     

航天器挠性板系统的模态分析和模型降阶

大型航天器上的太阳帆板这种悬臂外伸薄板结构挠性附件,由于存在模型不确定性及外部扰动条件下所引起的振动控制问题,为了易于低维控制器的设计以及降低控制“溢出”,需要建立板系统的低阶模型。对挠性悬臂板系统动力学模型分析采用模态展开技术,并利用模态截断方法、基于平衡实现的截断方法和平衡奇异摄动截断方法对挠性悬臂板进行了模型降阶,得到板系统的低阶模型,然后分析了降阶模型幅值误差。这为基于智能结构控制悬臂板控制器的设计提供了参考,数字仿真结果验证了方法的可行性。     

后掠平板横流不稳定性

本文研究了无限后掠平板三维边界层的横流不稳定性，证明行进波和定常波几平同时失稳，且行进波比定常波更不稳定；     

电刷架精密塑压模的研制

针对电刷架零件的使用功能,在对压塑、挤塑两种成形方法进行比较的基础上,确定了压塑成形。在压塑模上设计了弹片镶块和安装附件,并在出模时与塑件同步顶出等工艺方法,成功试制出了合格零件。     

确定高速碰撞试验中碎片特性的测试技术

文章介绍了高速碰撞试验中碎片特性的几种测试技术,软捕获技术、照相技术、间接测量技术,及其适用情况。     

推力室多孔面板发汗冷却试验研究

为了研究液体火箭发动机推力室喷注器多孔面板发汗冷却特性,以缩比推力室挤压热试验的形式开展了多孔面板发汗冷却特性研究,试验采用常温气氢对喷注器多孔面板进行发汗冷却。发汗冷却试验共进行5次,燃烧室压力为3.9～7.6 MPa,燃烧室氢氧混合比为2.8～7.2。研究结果表明在本试验研究状态下面板燃气侧温度为680～830 K...     

超声速气流中平板的颤振分析

对超声速气流作用下的矩形平板进行了颤振分析,采用一阶活塞理论计算准定常气动力,利用弹性力学理论和结构动力学理论建立了平板的运动平衡方程。采用梁模态构造矩形平板的近似模态函数。运用MATLAB软件编程画出平板在不同参数下的有关图形,研究了这些参数变化对平板稳定性的影响规律。分析结果可知,结构的所有模态中只有部分模态与颤振发生直接有关。这些模态是成对出现的,并且只有特定的两个模态频率重合才能发生颤振。     

Semi-analytic Solution of Steady Temperature Fields During Thin Plate Welding

Usually, it is very difficult to find out an analytical solution to thermal conduction problems during high temperature welding. Therefore, as an important numerical approach, the method of lines (MOLs) is introduced to solve the temperature field characterized by high gradients. The basic idea of the method is to semi-discretize the governing equation of the problem into a system of ordinary dif-ferential equations (ODEs) defined on discrete lines by means of the finite difference method, by which the thermal boundary condition with high gradients are directly embodied in formulation. Thus the temperature field can be obtained by solving the ODEs. As a numeri-cal example, the variation of an axisymmetrical temperature field along the plate thickness can be obtained.