基于变型设计理论的系列产品平台设计方法研究

应用变型设计理论和方法,对系列产品平台设计方法进行研究,探索覆盖整个产品功能要求的系列产品平台设计方法(Platform Design for Variety简称PDFV)。提出采用量化计算的产品变型指标和关联指标作为外因和内因引起系列产品更新设计的指导工具,获取产品变化的趋势,研究部件所受到的外界因素的影响,用关联指标作为部件之间关联程度的批示器,使开发出的系列产品平台具有柔性,以确保平台以最低的成本派生新产品,为快速实现系列产品的变型设计和配置设计提供科学方法。产品变型指标和关联指标工具的组合完善了PDFV方法。以油料装备系列产品油罐车为实例,论述了产品变型指标和关联指标构建的步骤。阐明基于变型设计理论的系列产品平台的研究,对实现快速设计、降低产品开发成本具有重要意义。     

Electronic warfare in the optical band: Main features,examples and selected measurement data

The paper presents the possibilities of, and methods for, acquiring, analysing and processing optical signals in order to recognise, identify and counteract threats on the contemporary battleground. The main ways electronic warfare is waged in the optical band of the electromagnetic wave spectrum have been formulated, including the acquisition of optical emitter signatures, as well as ultraviolet (UV) and thermal (IR) signatures. The physical parameters and values describing the emission of laser radiation are discussed, including their importance in terms of creating optical signatures. Moreover, it has been shown that in the transformation of optical signals into signatures, only their spectral and temporal parameters can be applied. This was confirmed in experimental part of the paper, which includes our own measurements of spectral and temporal emission characteristics for three types of binocular laser rangefinders. It has been further shown that through simple registration and quick analysis involving comparison of emission time parameters in the case of UV signatures in “solar-blind” band, various events can be identified quickly and faultlessly. The same is true for IR signatures, where the amplitudes of the recorded signal for several wavelengths are compared. This was confirmed experimentally for UV signatures by registering and then analyzing signals from several events during military exercises at a training ground, namely Rocket Propelled Grenade (RPG) launches and explosions after hitting targets, trinitrotoluene (TNT) explosions, firing armour-piercing, fin-stabilised, discarding sabots (APFSDS) or high explosive (HE) projectiles. The final section describes a proposed model database of emitters, created as a result of analysing and transforming the recorded signals into optical signatures.     

Investigation on the process parameters of TIG-welded aluminum alloy through mechanical and microstructural characterization

Multi-pass TIG welding was conducted on plates (15×300×180 mm3) of aluminum alloy Al-5083 that usually serves as the component material in structural applications such as cryogenics and chemical processing industries. Porosity formation and solidification cracking are the most common defects when TIG welding Al-5083 alloy, which is sensitive to the welding heat input. In the experiment, the heat input was varied from 0.89 kJ/mm to 5 kJ/mm designed by the combination of welding torch travel speed and welding current. Tensile, micro-Vicker hardness and Charpy impact tests were executed to witness the impetus response of heat input on the mechanical properties of the joints. Radiographic inspection was performed to assess the joint's quality and welding defects. The results show that all the specimens displayed inferior mechanical properties as compared to the base alloy. It was established that porosity was progressively abridged by the increase of heat input. The results also clinched that the use of me-dium heat input (1-2 kJ/mm) offered the best mechanical properties by eradicating welding defects, in which only about 18.26% of strength was lost. The yield strength of all the welded specimens remained unaffected indicated no influence of heat input. Partially melted zone (PMZ) width also affected by heat input, which became widened with the increase of heat input. The grain size of PMZ was found to be coarser than the respective grain size in the fusion zone. Charpy impact testing revealed that the absorbed energy by low heat input specimen (welded at high speed) was greater than that of high heat input (welded at low speed) because of low porosity and the formation of equiaxed grains which induce better impact toughness. Cryogenic (-196 C) impact testing was also performed and the results corroborate that impact properties under the cryogenic environment revealed no appreciable change after welding at designated heat input. Finally, Macro and micro fractured surfaces of tensile and impact specimens were analyzed using Stereo and Scanning Electron Microscopy (SEM), which have supported the experimental findings.     

Cooperative interception with fast multiple model adaptive estimation

For the case that two pursuers intercept an evasive target, the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target, which performs a bang For the case that two pursuers intercept an evasive target, the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target, which performs a bang-bang evasive maneuver with a random switching time. Combined Fast multiple model adaptive estimation (Fast MMAE) algorithm, the cooperative guidance law takes detection configuration affecting the accuracy of interception into consideration. Introduced the detection error model related to the line-of-sight (LOS) separation angle of two interceptors, an optimal cooperative guidance law solving the optimization problem is designed to modulate the LOS separation angle to reduce the estimation error and improve the interception performance. Due to the uncertainty of the target bang-bang maneuver switching time and the effective fitting of its multi-modal motion, Fast MMAE is introduced to identify its maneuver switching time and estimate the acceleration of the target to track and intercept the target accurately. The designed cooperative optimal guidance law with Fast MMAE has better estimation ability and interception performance than the traditional guidance law and estimation method via Monte Carlo simulation.     

Simulation on the dynamic stability derivatives of battle-structure-damaged aircrafts

Accurately evaluating the aerodynamic performance of a battle-structure-damaged aircraft is essential to enable the pilot to optimize the flight control strategy. Based on CFD and rigid dynamic mesh techniques, a numerical method is developed to calculate the longitudinal and longitudinal-lateral coupling forces and moments with small amplitude sinusoidal pitch oscillation, and the corresponding dynamic de-rivatives of two fragment-structure-damaged and two continuous-rod-damaged models modified from the SACCON UAV. The results indicate that, at the reference point set in this paper, additional positive damping is generated in fragment-damaged configurations; thus, the absolute values of the negative pitch dynamic derivative increase. The missing wingtip induces negative pitch damping on the aircraft and decreases the value of the pitch dynamic derivative. The missing middle wing causes a noticeable increase in the absolute value of the pitch dynamic derivative;the missing parts on the right wing cause the aircraft to roll to the right side in the dynamic process, and the pitch-roll coupling cross dynamic derivatives are positive. Moreover, the values of these derivatives increase as the damaged area on the right wing increases, and an optimal case with the smallest cross dynamic derivative can be found to help improve the survivability of damaged aircraft.     

Preparation and characterization of HMX/EVA/hBNNSs micro-composites with improved thermal stability and reduced sensitivity

Hexagonal boron nitride nanosheets(HBNNSs)have huge potential in the field of coating materials owing to their remarkable chemical stability,mechanical strength and thermal conductivity.Thin-layer hBNNSs were obtained by a liquid-phase exfoliation of h-BN powders and incorporated into EVA coatings for improving the safety performance of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX).HBNNSs and ethylene-vinyl acetate copolymer(EVA)were introduced to HMX by a solvent-slurry process.For com-parison,the HMX/EVA and HMX/EVA/graphene(HMX/EVA/G)composites were also prepared by a similar process.The morphology,crystal form,surface element distribution,thermal decomposition property and impact sensitivity of HMX/EVA/hBNNSs composites were contrastively investigated.Results showed that as prepared HMX/EVA/hBNNSs composites were well coated with hBNNSs and EVA,and exhibited better thermal stability and lower impact sensitivity than that of HMX/EVA and HMX/EVA/G composites,suggesting superior performance of desensitization of hBNNSs in explosives.     

机场道面抢修应急起降带的确定

应急起降带的确定是战时机场道面抢修的基础性工作,对抢修工程量、抢修效率、抢修进程都有着重大影响.首先介绍了应急起降带合理尺寸的确定;然后提出了应急起降带最佳抢修位置的确定原则;为了实现应急起降带方案的快速优选,用VB编写了方案优选程序,改变了传统的人工优选法费时费力的现状.从文中的实例分析可以得出结论:该方案优选程序的运算结果满足实际抢修施工需要.     

基于坐标转换的卡尔曼交互式多模型滤波算法

为解决舰炮火控系统中在笛卡尔坐标系中测量信息的互相关性,分析了目前舰炮火控系统中所用到的坐标系及其坐标变换,在瞄准线坐标系内建立了自适应滤波的交互式多模型算法,能够充分利用跟踪传感器的量测信息,在卡尔曼滤波中具有较强的自适应能力,通过与标准交互式多模型算法的对比验证,自适应交互式多模型算法在计算精度上明显好于标准交互式多模型算法。     

三维多站测向交叉定位算法及精度分析

在多站的测向交叉定位中,常把三维问题分解成二维和一维分别解算,这种方法虽简单易行,但定位精度有待进一步的提高。文中详细推算了这种算法的误差模型;然后给出一种用泰勒级数法结合最小二乘的思想进行定位的方法,并通过仿真计算证明了这种泰勒级数法的定位性能要优于前者。     

测控站布局对区域卫星导航系统的影响

建立区域卫星导航系统的测控网是卫星导航系统要解决的关键问题之一。讨论国内测控站的布设问题,采用网格计算方法分析国内测控站对导航星座的可观测性。引入位置精度衰减因子PDOP和定轨中的法矩阵条件数,分析测控网对导航星座的观测几何结构强度以及测站位置分布对轨道确定精度的影响,仿真结果表明,利用我国有限的国土跨度和航天测控资源可以确保对导航卫星的测控任务的完成。对在国外布设测控站进行讨论和仿真,结果说明位于国外的测控站(如可在澳大利亚的珀斯设站)的加入能明显改善观测的几何结构强度、提高导航卫星的轨道精度。