面向无人机航路规划的威胁建模研究（英文）

无人机的航路规划是提高其生存概率的必要手段,威胁建模则是航路规划的关键技术之一。为满足研究的实际需求,支持快速的航路规划,要求在规划前期能够迅速给出对威胁模型的初始描述,针对无人机航路规划问题,提出了基于模糊综合评判建立威胁模型的新方法,并通过一个仿真实例验证了该方法的有效性。     

多架无人机协同航迹规划研究综述

多架无人机协同执行任务已经成为未来无人机发展的重要趋势,多无人机协同航迹规划是保障多无人机协同完成任务的重要手段之一。文章系统梳理了多无人机协同航迹规划研究现状,归纳现有多无人机协同航迹规划方法,从搭建航迹规划仿真地图、明确多机协同评价指标和选择规划算法三个方面阐述多无人机协同航迹规划实现方法,最后对协同航迹规划技术的发展进行了展望:提高无人机群的自主性、协同性和规划算法性能是多无人机协同航迹规划的发展趋势,最终有望实现无人机群在任何情况下都能够快速自主规划最优航迹并同时保持多无人机空间和时间上的协同。研究高精度的无人机航迹规划仿真地图、合理的多机协同结构对提高多无人机协同航迹规划技术也具有较大的实践意义。     

无人机撞击民机发动机叶片动态响应及破坏损伤数值研究

采取ABAQUS软件作为系统框架，该软件为非线性动力软件，结合拉格朗日算法作为基础，公共搭建一套应用于无人机装机民机中核心零件的数值模型。其中核心部件中包括了针对无人机被民机发动机吸入到风扇叶片发生撞击的仿真模型，采用不同场景下的工况进行仿真分析与计算，以此获取撞击过程中的动力响应规律以及导致民机动力失效损伤的经过。仿真模拟结果表明:在民机的发动机风扇叶片被无人机撞击以后，风扇转速的变化是无人机对发动机撞击部位带来损伤差异的关键因素；无人机撞击民机造成关键部件损伤的主要来源是无人机内嵌的硬质体锂电池和小电机。     

基于改进人工蜂群算法的无人机航迹规划研究

为应对无人机遇到的复杂任务状况,快速寻找一条可行较优航迹,通过改进初始化蜜源方式、引入模拟退火算法的Metropolis准则、引入复合形法等对人工蜂群算法进行改进,提出了一种基于改进人工蜂群算法的无人机航迹规划方法。针对无人机航迹规划问题建立数学模型,采用该改进人工蜂群算法进行寻优,并通过MATLAB进行仿真验证。仿真实验结果表明,该改进人工蜂群算法有效提高了无人机航迹规划的鲁棒性、收敛速度和精度。     

基于改进人工蜂群算法的无人机三维航迹规划

为应对无人机遇到的复杂任务状况,提高航迹规划效率,提出一种基于改进人工蜂群算法的无人机三维航迹规划方法。为降低无人机三维航迹规划的难度,将航迹规划数学模型通过简化建模转化为函数优化问题;为提高航迹优化效率,通过改进蜜源初始化方式、引入动态评价选择策略、引入Metropolis准则等方式对传统人工蜂群算法在该问题求解中的缺陷进行改进,通过MATLAB进行20次仿真实验,验证了改进人工蜂群算法在无人机三维航迹规划中的可行性和优化效率。     

面向WSNs节点数据采集的无人机Voronoi图路径规划

尽管利用无人机能够提高收集无线传感网络内节点数据的效率,但无人机的移动路径是一个非凸的优化问题。为此,提出基于Voronoi图的无人机路径规划(VDO-UAV)算法。VDO-UAV算法旨在保证收集所有节点数据的前提下,缩短无人机遍历路径。先对Voronoi图进行修改;再利用Voronoi图的顶点或边与参考路径的交点或Voronoi中心构建UAU盘旋的位置;并优先利用Voronoi图的顶点作为无人机盘旋的位置,进而尽可能在一个盘旋位置收集更多节点数据。仿真结果表明,提出的VDO-UAV算法缩短了UAV遍历路径,并降低算法的复杂度。     

无人机水下发射试验系统弹射性能的仿真研究

为研究无人机水下发射的可行性及其弹射过程动力学性能，对系统主要参数进行影响规律和灵敏度分析。通过研究机械结构和传动系统的耦合特性，建立基于AMESim和ADAMS的水下发射试验系统动力学联合仿真模型，在发射角10°～90°范围内对3种类型无人机进行仿真，得到发射速度随发射角和储气瓶压力的变化规律；利用局部灵敏度分析方法，对储气瓶压力、储气瓶容积、气缸有效面积和行程4个关键参数进行了影响发射速度和加速时间的规律分析。结果表明：在相同压力下，随着发射角的增大和无人机模型质量的减小，其脱离发射架的速度逐渐增大；影响发射速度灵敏度最大的参数为储气瓶压力，随着压力的增大，速度增大的幅度逐渐减小；影响加速过程时间灵敏度最大的参数为储气瓶压力和气缸有效面积。     

一种无人机回收系统蓄能器能量回收效率研究

为减少无人机回收过程中能量浪费,采用以蓄能器为储能元件的无人机回收过程能量回收系统。推导系统主要组件的数学模型,搭建系统的AMESim模型并进行仿真。研究蓄能器体积、蓄能器预充压力、回收装置质量、无人机质量对能量回收效率的影响。结果表明：蓄能器体积、蓄能器预充压力、无人机质量对回收效率影响较大,是影响蓄能器能量回收效率的关键参数。     

并行工程环境下协同式检测规划模型的研究

计算机辅助检测规划已经是现代制造系统中不可缺少的重要组成部分，传统的检测规划集成系统已经不能满足面向工程的检测规划的要求。本文在分析检测规划的基础上介绍了基于并行工程哲理的协同式检测规划系统模型，并从三个层次介绍其模型，其思想方法形成了并行工程环境下ＣＡＩＰ的完整的解决方案。     

无人机在城镇高压燃气管道巡线中的应用

天然气高压管道遍布佛山市内五区，负责接收所有进入佛山的燃气气源，对城市燃气供应发挥重要作用。成为推动佛山经济发展的重大能源动力。佛山市高压燃气管道分布错综复杂，管道遭受破坏的因素众多，人工巡检难以全面覆盖。随着无人机技术的日渐成熟，自2015年佛山市天然气高压管网有限公司引入无人机巡线技术，极大提高了巡线效率，使得高压管道巡查覆盖面达到最大化。在完成巡线任务的同时，还可利用无人机观测燃气场站情况，让燃气场站管理效率得到提高。本文结合实际巡线情况，对比了多旋翼和固定翼两种无人机的类型和性能，分析了无人机应用的可行性，选择适合高压燃气管道巡查工作的无人机类型，并明确后期的研究方向。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.