有限元动力模型优化的一种方法

本文研究以振动试验测得的飞机结构的固有频率为目标值的有限元动力模型的优化问题。应用了一种迭代优化法,该方法基于动力平衡方程以及正交性。通过修改刚度矩阵的元素来优化,使计算出的固有频率与试验测得的频率值基本一致,并成功地应用于无人机水平尾翼模型上,效果良好。     

求解最小费用流的复合标号法

本文在求最短路和求最大流标号法的基础上,提出了求解最小费用流的复合标号法。利用这种方法可以在一次标号的过程中找到具有最小费用的增广链。该算法具有简单、易行、迭代次数少,而且易于理解的特点。     

采用逐次正交化法的最优分布式Kalman滤波器

为解决大系统中应用整体式Kalman滤波遇到的非实时性难题,本文提出一种能保持最优的分布式Kalman滤波计算方法——逐次正交化法。这是一种适合多微机并行计算的最优算法,确保滤波的“实时性”,优于一般次优分布式Kalman滤波器。     

羊毛精纺织物服用性能优选的多属性模糊决策

本文应用多属性目标决策的方法,评判不同规格毛织面料的"满意度",客观地提供一个重要的优选辅助依据。     

双层多目标规划若干问题的研究

研究了下层决策者无关联的双层多目标规划问题，在不同偏好意义下，给出了各自解的定义，讨论了线性双层多目标规划问题。     

结构优化中的混合变量应力约束近似方法

提出一种处理结构优化应力约束的新近似方法，以往一般直接对应力约束按设计变量近似，本文用近似内力间接近似应力约束以得到更高的近似质量，根据对内力和设计变量关系分析，提出了内力按混合变量一阶泰勒展开的高捏近似方法。近似优化问题用约束变尺度法求解，最后按出了几个典型例题。结果表明该方法简单，有效，可靠。     

基于参数化模型和遗传算法的复合材料加筋壁板结构选型优化研究

针对复合材料加筋壁板的结构优化选型问题,采用辅助层压板和添加极小弹性模量材料的复合材料加筋壁板有限元建模方法,应用PATRAN/NASTRAN的参数化建模功能和遗传算法相结合的复合材料加筋壁板的优化方法,对5种复合材料结构形式进行了从2000N/mm到6000N/mm压缩载荷下的结构优化分析。结果表明,当载荷小于4500N/mm时,最有效的加筋壁板结构型式为J型;当压缩载荷大于4500N/mm时,最有效的加筋壁板结构型式为I型。     

Hybrid integration method for highly maneuvering radar target detection based on a Markov motion model

To detect highly maneuvering radar targets in low signal-to-noise ratio conditions, a hybrid long-time integration method is proposed, which combines Radon-Fourier Transform (RFT), Dynamic Programming (DP), and Binary Integration (BI), named RFT-DP-BI. A Markov model with unified range-velocity quantification is formulated to describe the maneuvering target’s motion. Based on this model, long-time hybrid integration is performed. Firstly, the whole integration time is divided into multiple time segments and coherent integration is performed in each segment via RFT. Secondly, non-coherent integration is performed in all segments via DP. Thirdly, 2/4 binary integration is performed to further improve the detection performance. Finally, the detection results are exported together with target range and velocity trajectories. The proposed method can perform the long-time integration of highly maneuvering targets with arbitrary forms of motion. Additionally, it has a low computational cost that is linear to the integration time. Both simulated and real radar data demonstrate that it offers good detection and estimation performances.     

Influence of TiB2 particles on machinability and machining parameter optimization of TiB2/Al MMCs

In situ formed TiB₂ particle reinforced aluminum matrix composites (TiB₂/Al MMCs) have some extraordinary properties which make them be a promising material for high performance aero-engine blade. Due to the influence of TiB₂ particles, the machinability is still a problem which restricts the application of TiB₂/Al MMCs. In order to meet the industrial requirements, the influence of TiB₂ particles on the machinability of TiB₂/Al MMCs was investigated experimentally. Moreover, the optimal machining conditions for this kind of MMCs were investigated in this study. The major conclusions are: (1) the machining force of TiB₂/Al MMCs is bigger than that of non-reinforced alloy and mainly controlled by feed rate; (2) the residual stress of TiB₂/Al MMCs is compressive while that of non-reinforced alloy is nearly neutral; (3) the surface roughness of TiB₂/Al MMCs is smaller than that of non-reinforced alloy under the same cutting speed, but reverse result was observed when the feed rate increased; (4) a multi-objective optimization model for surface roughness and material removal rate (MRR) was established, and a set of optimal parameter combinations of the machining was obtained. The results show a great difference from SiC particle reinforced MMCs and provide a useful guide for a better control of machining process of this material.     

基于线性规划的多操纵面重构控制研究

为实现多操纵面飞机的重构控制,提高飞机飞行的安全性能,提出了一种基于线性规划的多操纵面重构控制策略.针对操纵面卡死、松浮、损伤等典型故障情况,推导了相应的重构分配器,通过基于线性规划的直接分配方法来实现在操纵面故障下的重构控制.仿真结果表明,该控制策略能有效处理典型操纵面故障,发生故障时仍能快速跟踪控制指令,保证较好的...