H型动压气体轴承轴套端面平面度制造误差分析

针对H型动压气体轴承端面平面度指标问题,从轴承端面研磨的定位夹具、工艺方法入手,分析了研磨工艺方法对端面平面度带来系统误差,并根据加工时的装配状态及操作方法,提出了改进措施,从而达到进一步提高平面度指标的目的.     

风洞试验中的视频测量技术现状与应用综述

视频测量（Videogrammetric Measurement,VM）技术因其对试验模型的设计制造无要求,受到国内外风洞试验机构的青睐,本文综述了国外航空航天强国的风洞试验机构所掌握的 VM 技术,并分析了 VM 技术在我国高速暂冲风洞试验中应用所面临的问题,据此中国空气动力研究与发展中心（CARDC）提出了多相机动态标定与基于运动估计的序列图像匹配技术,在暂冲高速风洞高噪声（130 dB 左右）振动环境下,建立了高精度的模型位姿光学测量技术,2米量级高速风洞中的多个应用表明：视频测量的精度高,已用于高速试验模型的姿态与变形测量;另一方面,通过 VM 测量偏折位移场得到光束从摄影中心出发穿过扰流区的光程差,为气动光学效应的研究与测量以及试验模型的壁面流动显示提供新的途径,其光路简单、无需使用价格昂贵的相干光源,因此具有巨大应用前景。     

航天器蜂窝夹层结构复合材料热变形分析

蜂窝夹层结构复合材料在航空、航天结构中已得到了广泛的应用。文章从热变形分析角度出发，对蜂窝夹层结构复合材料的热变形分析问题提出了几点看法。     

固体火箭发动机药柱三维结构非线性分析

非线性分析是药柱结构分析中的难点，针对其对结构分析的影响，基于不可压缩材料的粘弹性本构关系，应用完全拉格朗日（T．L）法的虚功方程，综合考虑药柱的近似不可压缩性和几何非线性，推导了三维粘弹性几何非线性有限元增量方程，编写了有限元程序对星型药柱在受压力载荷以及固化降温载荷作用下的结构进行了分析，并与线性计算的结果进行了对比，结果表明，在大载荷作用下，非线性对药柱结构分析的影响比较显著，计算时考虑非线性的影响是必要的。     

液体火箭发动机喷管收扩段的数控加工工艺研究

液体火箭发动机中，喷管收扩段是一个关键零件，数控加工工艺方法和程序编制方法非常复杂，国内外均在该方面有所研究。本文简述了喷管收扩段的数控加工工艺和程序编制方法以及在程序编制过程中建立的数学模型，并在通用的数控铣加工中心上实现了该零件的数控加工。     

挠性空间结构变形的自适应辨识

本文以空间控制中的挠性结构变形的辨识为背景,以李雅普诺夫稳定性理论为基础,从辨识的一致性原则出发,给出时变参数的自适应辨识算法。该算法具有梯度型递推形式,结构简单、容易实现。计算机模拟结果表明该算法是解决时变参数辨识的一种有效方法。     

基于NURBS曲面的轴变形方法

对基于ＮＵＲＢＳ曲面提出一种轴变形方法。该方法首先定义一条轴线，使物体上每一点与轴上一点对应，然后通过操纵轴的变形来变形物体。该方法用于三维人体模型的建立取得满意效果。     

Simulation and experimental investigation on a dynamic lateral flow mode in trepanning electrochemical machining

An appropriate flow mode of electrolyte has a positive effect on process efficiency, surface roughness, and machining accuracy in the electrochemical machining(ECM) process. In this study, a new dynamic lateral flow mode, in which the electrolyte flows from the leading edge to the trailing edge, was proposed in trepanning ECM of a diffuser. Then a numerical model of the channel was set up and simulated by using computational fluid dynamics software. The result showed that the distribution of the flow field was comparatively uniform in the inter-electrode gap. Furthermore, a fixture was designed to realize this new flow mode and then corresponding experiments were carried out. The experimental results illustrated that the feeding rate of the cathode reached 2 mm/min, the best taper angle was about 0.4°, and the best surface roughness was up to Ra= 0.115 lm. It reflects that this flow mode is suitable and effective, and can also be applied to machining other complex structures in trepanning ECM.     

Computational study of wing deformation and sting interference effects with the CAE-AVM test case

A modern transonic computational fluid dynamics test case is described in this paper, which is the Aerodynamic Validation Model (AVM) from the Chinese Aeronautical Establishment (CAE). The CAE-AVM is a representation of a modern transonic business jet aircraft with a design Mach number of 0.85. Numerical simulations for the AVM are conducted for two geometries: one baseline geometry, and one geometry that includes the applied model support system of the wind tunnel as well as the deformed wing shape that occurred during wind tunnel testing. The combined influence of wing deformation and model support interference on local and integral aerodynamic features is presented. Comparisons between CFD and experimental results are made; reasons of discrepancy between results from considered cases are analyzed.     

Numerical studies of static aeroelastic effects on grid fin aerodynamic performances

The grid fin is an unconventional control surface used on missiles and rockets. Although aerodynamics of grid fin has been studied by many researchers, few considers the aeroelastic effects.In this paper, the static aeroelastic simulations are performed by the coupled viscous computational fluid dynamics with structural flexibility method in transonic and supersonic regimes. The developed coupling strategy including fluid–structure interpolation and volume mesh motion schemes is based on radial basis functions. Results are presented for a vertical and a horizontal grid fin mounted on a body. Horizontal fin results show that the deformed fin is swept backward and the axial force is increased. The deformations also induce the movement of center of pressure, causing the reduction and reversal in hinge moment for the transonic flow and the supersonic flow,respectively. For the vertical fin, the local effective incidences are increased due to the deformations so that the deformed normal force is greater than the original one. At high angles of attack, both the deformed and original normal forces experience a sudden reduction due to the interference of leeward separated vortices on the fin. Additionally, the increment in axial force is shown to correlate strongly with the increment in the square of normal force.