飞控系统模糊控制器设计及稳定性分析

建立了飞控系统的Ｔａｋａｇｉ－Ｓｕｇｅｎｏ（Ｔ－Ｓ）模糊模型;给出了设计模糊状态反馈控制器,保证闭环系统全局渐近稳定、具有一定衰减率稳定的两个充分条件;提出了采用线性矩阵不等式（ＬＭＩ）方法,将该充分条件转化为对线性矩阵不等式族寻求ＬＭＩ可行解的凸优化问题,得到了稳定性分析和模糊状态反馈控制器设计的新方法。仿真结果表明,所提出的设计方法方便有效,控制器鲁棒性好。     

陶瓷基复合材料在喷管上的应用

综述了国外Ｃ／ＳｉＣ陶瓷基复合材料在火箭发动机喷管上的应用现状,重点介绍了法国ＳＥＰ生产Ｃ／ＳｉＣ复合材料喷管扩张段的成型技术以及连接与机加、材料性能等。最后对Ｃ／ＳｉＣ复合材料在固体火箭发动机上的应用前景进行了展望。     

Investigation on surface roughness,residual stress and fatigue property of milling in-situ TiB2/7050Al metal matrix composites

For higher efficiency and precision manufacturing, more and more attentions are focused on the surface roughness and residual stress of machined parts to obtain a good fatigue life. At present, the in-situ TiB₂/7050Al metal matrix composites are widely researched due to its attractive properties such as low density, good wear resistance and improved strength. It is of great significance to investigate the machined surface roughness, residual stress and fatigue life for higher efficiency and precision manufacturing of this new kind material. In this study, the surface roughness including two-dimensional and three-dimensional roughness, residual stress and fatigue life of milling in-situ TiB₂/7050Al metal matrix composites were analyzed. It was found from comparative investigation that the three-dimensional surface roughness would be more appropriate to represent the machined surface profile of milling particle reinforced metal matrix composites. The cutting temperature played a great role on the residual stress. However, the effect of increasing cutting force could slow down the transformation from compressive stress to tensile stress under 270 °C. An exponential relationship between three-dimensional roughness and fatigue life was established and the main fracture mechanism was brittle fracture with observation of obvious shellfish veins, river pattern veins and wave shaped veins in fracture surface.     

Machining of SiC ceramic matrix composites: A review

Continuous fiber reinforced SiC ceramic matrix composites (FRCMCs-SiC) are currently the preferred material for hot section components, safety–critical components and braking components (in the aerospace, energy, transportation) with high value, and have triggered the demand for machining. However, the high brittleness, anisotropy, and heterogeneity of materials bring great challenges to machining, due to high mechanical and thermal loads, severe tool wear, and poor machining quality. With the increasing demand of FRCMCs-SiC parts, high-quality and high-efficient machining has become a hot issue. This review paper provides a detailed literature survey on the machining of FRCMCs-SiC. The material removal mechanism, defect form, and interfacial mechanical properties of FRCMCs-SiC were summarized. The machining processes of FRCMCs-SiC were introduced, and their respective advantages and disadvantages were compared. Given the low machinability (high hardness, high brittleness, anisotropy, and heterogeneity) of FRCMCs-SiC, preliminary experiments have proved that ultrasonic-assisted machining and laser-assisted machining have shown unique advantages in reducing force and tool wear, improving machining quality and machining efficiency. The machined surface integrity was discussed, the influence of process parameters on the machined surface quality was analyzed, and the machining defects of FRCMCs-SiC were summarized. But for FRCMCs-SiC, the existing quantitative evaluation of the machined surface integrity was weak and unsystematic.     

求解大型矩阵特征值问题的并行块Davidson方法

针对拥有共享内存的并行计算环境和微机网络并行计算环境,给出了求解大型稀疏对称矩阵部分极端特征对的并行块Davidson方法。该方法将矩阵A按行块分配到各处理器上,各处理器利用矩阵A的行块和投影子空间的正交基所组成矩阵V的行块进行运算,减少了处理机之间的通讯次数,实现了算法的并行计算。在微机网络并行计算环境和拥有共享内存并行计算环境IBMP650上的数值试验表明,该算法非常有效。     

飞机静不定结构非线性应力计算—参考模量法

应用虚拟载荷法解飞机静不定结构非线性应力，当非线性充分发展时，因虚载荷过大而导致发散。本文提出参考模量法，使虚载荷减小，从而使收敛性大大提高。     

关于约束分类问题的研究

约束条件的分类对于简化数学规划问题的求解具有重要意义，对于凸函数ｇｉ（ｘ）（ｉ＝１，２，…，ｎ）给出了约束ｇｉ（ｘ）≤０是必要约束或多余约束的充要条件，对于一般约束，定义了约束相关矩阵，给出了约束是必要的或多余的充要条件，对相对多余约束给出了分类。     

SiC/Al复合丝的耐蚀性和高温稳定性研究

本研究结果表明,SiC/L_6和SiC/LF_6复合丝在真空中加热至600℃和在空气中400℃暴露144小时,以及在蒸馏水和5%NaCl水溶液中浸泡15天后,其强度保留率大于87%,证明SiC/Al复合丝具有良好的耐蚀性和高温稳定性,用气相层析仪和发射光谱分析了腐蚀气体、溶液和白色沉淀,初步确定其反应机理是电化学腐蚀。与C/Al复合丝相比,SiC/Al腐蚀速度缓慢,纤维—基体界面损伤极小。     

投入产出理论中两种消耗系数关系的新推证

从随机过程中状态转移矩阵的概仿出发，对投入产出理论中从直接消耗系数Ａ求得完全消耗系数矩阵Ｔ，提出一种新的推证方法，证明了Ａ与Ｔ之间的数量依存关系。     

拟线性最优平滑滤波及其应用

在普通推广卡尔曼滤波（Ｅ．Ｋ．Ｆ．）的基础上，提出了一种更加适用于非线性状态方程和观测方程的改进的滤波算法－－拟线性最优平滑滤波（Ｑ．Ｌ．Ｏ．Ｓ．Ｆ．）算法，在求该滤波算法的状态转移矩阵时，加进了二阶导数项，同时线性化的标称值取为单步平滑值，降低了非线性对滤波的影响，提高了滤波精度。通过对某歼击机的仿真飞行试验数据及实测数据的处理，表明该算法比普通推广卡尔曼滤波具有更好的收敛性、精确性。