LXI仪器的LAN设置及控制

在介绍了LXI仪器类型、Non Auto-MDIX含义、Agilent33220A函数发生器性能和功能的基础上,以33220A函数/任意波形发生器的LAN接口设置为例,描述了其LAN接口DHCP,Auto IP,IP Address,SubnetMask,Default Gateway,Host Name,Domain Name,DNS Server,Password等参数的含义、设置方法,介绍了充分利用其提供的接口功能,达到远程控制其输出的方法。该方法达到了通过GPIB控制函数/任意波形发生器的同样效果,利用其LAN接口组建分布式测试系统,对程序设计者具有较高的参考借鉴价值。     

液压阻尼器对模型旋翼地面共振的影响

 分析了某采用定压阀和补油装置的液压阻尼器的非线性特性。对无铰式模型旋翼的地面共振稳定性进行了数值仿真研究,分析了两种不同的非线性液压阻尼器对地面共振稳定性的影响。结果表明：由于补油分配阀间隙的影响,阻尼器低速时的有效阻尼大大下降;在无阻尼器的模型旋翼稳定的转速区内,该阻尼器不能改善系统小扰动情况时的动稳定性;在无阻尼器的模型旋翼不稳定区内,系统将出现极限环,且极限环幅值随补油分配阀间隙的增大而增大。研究结果对液压阻尼器的设计具有参考价值。     

Multi-objective Optimization Method for Automatic Drilling and Riveting Sequence Planning

 There are numerous riveting points on the large-sized aircraft panel, irregular row of riveting points on delta wing. It is es-sential to plan the riveting sequence reasonably to improve the efficiency and accuracy of automatic drilling and riveting. Therefore, this article presents a new multi-objective optimization method based on ant colony optimization (ACO). Multi-objective optimization model of automatic drilling and riveting sequence planning is built by expressing the efficiency and accuracy of riveting as functions of the points’ coordinates. In order to search the sequences efficiently and improve the quality of the sequences, a new local pheromone updating rule is applied when the ants search sequences. Pareto dominance is incorporated into the proposed ACO to find out the non-dominated sequences. This method is tested on a hyperbolicity panel model of ARJ21 and the result shows its feasibility and superiority compared with particle swarm optimization (PSO) and ge-netic algorithm (GA).     

典型前缘结构抗鸟撞性能改进研究

 针对某典型前缘结构,研究了使用纤维金属层板(Fibre Metal Laminates,FMLs)蒙皮进行抗鸟撞设计的可行性。以显式动态冲击分析程序PAM-CRASH为平台,结合由鸟撞平板试验结果验证的鸟体本构模型参数,建立了鸟撞前缘结构数值模型。通过计算研究了使用不同蒙皮(铝合金、FMLs)的前缘结构在鸟撞作用下的变形破坏模式及吸能效果。结果表明：采用适当铺层的FMLs蒙皮可以有效地提高前缘结构的抗鸟撞性能。研究结论对飞机结构的抗鸟撞研究具有一定的参考价值。     

Environmental stress level evaluation approach based on physical model and interval grey association degree

 Associating environmental stresses (ESs) with built-in test (BIT) output is an important means to help diagnose intermittent faults (IFs). Aiming at low efficiency in association of traditional time stress measurement device (TSMD), an association model is built. Thereafter, a novel approach is given to evaluate the integrated environmental stress (IES) level. Firstly, the selection principle and approach of main environmental stresses (MESs) and key characteristic parameters (KCPs) are presented based on fault mode, mechanism, and ESs analysis (FMMEA). Secondly, reference stress events (RSEs) are constructed by dividing IES into three stress levels according to its impact on faults; and then the association model between integrated environmental stress event (IESE) and BIT output is built. Thirdly, an interval grey association approach to evaluate IES level is proposed due to the interval number of IES value. Consequently, the association output can be obtained as well. Finally, a case study is presented to demonstrate the proposed approach. Results show the proposed model and approach are effective and feasible. This approach can be used to guide ESs measure, record, and association. It is well suited for on-line assistant diagnosis of faults, especially IFs.     

大尺寸薄壁钛合金筒体结构的离心精密铸造

采用离心精密铸造方法,初步研究了铸造大尺寸薄壁钛合金筒体(直径660 mm,高750 mm,壁厚4 mm)的可行性。结果表明:离心转速较小时,Ti-6Al-4V筒体无法完整充型,而较大的转速可实现完整充型。对于完整充型的筒体,其内部疏松缺陷数量随转速提高而减少。对于给定转速和具有均匀温度场的型壳,筒体中疏松缺陷数量随熔液路径增长而增加。采用Y2O3面层型壳可获得无α壳层的表面质量良好的精密铸件,其内部疏松可通过热等静压消除。铸件的晶粒度随铸件截面厚度变化改变较大,需通过微合金化和后续热处理等措施加以调整。     

航空产品电子元器件的质量控制

航空产品的最基本单元是电子元器件,高可靠性的航空产品意味着必须有高可靠性的元器件。对电子元器件应从选用、二次筛选、破坏性物理分析(DPA)、失效分析、质量跟踪、建立元器件质量数据库等方面进行有效的控制,从而确保装机电子元器件的质量。     

湍流附面层壁面摩擦应力的测量方法

 本文讨论了不可压和可压湍流附面层壁面摩擦应力的测量方法,对Presto管、Stanton管、底层隔板、表面热膜和计算Preston管法进行了校准和测量比较。     

结合响应面法与网格法的低速翼型优化设计

本文首先了介绍响应面法和网格法的基本原理,翼型绕流场分析使用有限体积法空间离散和RUNGE-KUTTA时间迭代格式进行N-S方程计算,由翼型表面压力和摩擦力数值积分得到升力和阻力.然后,以NACA0012和GAw-1为算例,结合响应面法和网格法进行低速翼型的减阻优化设计,算例表明:在应用响应面法进行低速翼型优化时,采用...