Torsion Failure Analysis of Galvanized Steel Wires for Transmission and Distribution Lines Based on ANSYS Numerical Simulation

This study provides a detailed failure analysis of galvanized steel wires(3 mm in diameter) for a 35 k V transmission and distribution line, which was carried out by combining the conventional material analysis methods with the finite element method(FEM). It is found that the failed material had good plasticity(5% in elongation),and under the soft torsion loading condition(0.75 in stress state soft coefficient), the ductile fracture should occur on the material. Additionally, the theoretical number of torsions calculated by the FEM was 26.2 times, while the actual number of torsions achieved by the test was only 2.2 times and the local fracture surface exhibited brittle fracture characteristics. The results showed that the local torsion brittle fracture of the material with good plasticity was caused by triaxial stress in the torsion condition, which led to the formation of cavity in the pulling stress area in the material's center, and the finite element calculation results indicated that the stress state soft coefficient at the cavity was distributed between 0.31 and 0.38, and the stress concentration at the cavity was more than twice the normal value. Besides, the Widmanstatten structure formed as the improper hot working process is the corresponding structural reason.     

基于机器视觉的吊弦动态抬升量测量方法

为研究吊弦的疲劳寿命问题须先对吊弦的动态抬升量进行定点实时测量,因此提出一种基于机器视觉的测量方法。首先,通过鼠标交互的方式,在输入视频流的第1帧图像上框选吊弦在接触线侧线夹处的图像作为初始模板图像,并将其中心点定义为初始测量点,以此确定测量的定位。在此基础上,基于二维离散余弦变换将模板图像的信息从图像域转换到频率域,选取其中低频信号代表的系数矩阵,通过哈希算法将该矩阵转换为哈希值,并对输入的每帧图像均采用模板匹配方法,实现对测量点的跟踪,提取测量点的像素坐标。然后,根据相机成像原理,建立吊弦抬升量测量模型,通过摄像机内参标定和坐标系逆变换推导出像素坐标与实际位移之间的转换公式,完成对吊弦动态抬升量的计算。为验证测量方法的有效性,选取京广高速铁路武汉至乌龙泉东区间段进行现场测试。结果表明：采用该方法处理单帧图像的时间仅需0.1 s,吊弦动态抬升量测量误差最大为4.6%,具有较高的测量精度,能够实时、有效地获得吊弦动态抬升量。     

舰空导弹引导射击方法中的误差传递分析

对舰空导弹引导射击的方法进行了阐述,分析了各环节所产生的误差及误差所服从的分布并构造了服从分布的随机数发生器,在此基础上利用蒙特卡罗法对误差传递后的误差量进行了模拟统计,并对仿真结果进行了分析。     

通过水雷障碍群的最短路径寻径问题研究

由最短路径的Dijkstra算法、Floyd算法和A^＊自启发算法出发,结合水雷障碍群的现实情况,提出了两种适合采用现有最短路径寻径算法解算得到快速安全通过水雷障碍群的最短路径的量化建模方法。在此基础上,该文还对其中一种量化模型的快速通过水雷障碍群最短路径的改良寻径算法进行了探讨和结果演示。     

利用面向对象法构建反导空中目标三维弹道仿真研究

利用面向对象的方法定义建立空中目标（包括反舰导弹和舰空导弹）三维弹道仿真所需的类并确定类的继承关系,研究实现类中空中目标的空间坐标表示和计算方法,依据一定作战要求及引导规律建立相应目标弹道模型,并进行三维弹道仿真结果演示。