摘要
电枢是同步感应电磁线圈炮(Synchronous Induction Coilgun,SICG)的一个关键部件,在线圈炮的发射过程中易发生破坏.为了保证SICG发射实验的顺利进行,对空心圆筒电枢的应变进行了测量.用电阻应变仪来测定应变是目前使用较多的一种方法,但SICG放电过程中产生的瞬间强磁场会使应变计感应极强的干扰信号,严重影响应变计的准确测量.根据惠斯登电桥原理,文中采取了内补偿法克服这种固有的电磁干扰,即将补偿片安装在工作片的上面,工作片与补偿片位于相同的空间位置,感受相同的物理效应,但补偿片没有工作片的力学变形,这样工作片与补偿片同步感受电磁干扰信号,在桥路中互相抵消,测得的仅是工作片的力学效应.基于动态应变测试原理搭建了单级SICG的实验装置,利用动态电阻应变仪对"零速度"电枢进行了应变测量,测出了电枢尾部应变随时间的变化规律;利用有限元软件对电枢进行了磁-结构耦合分析,得出了电枢的应力分布规律,以及电枢尾部的应力随时间的变化规律,与实验结果基本相符.
Armature was a key component of synchronous induction coilgun （SICG） which was susceptible to damage caused by enormous electromagnetic forces during the launching process. Strain measurement of the cylinder-shaped armature was carried out to guarantee the success launching experiment of SICG. The resistance strain gauge method is the most commonly used method to measure the strain. But in the launching of SICG, intense interference signals were induced in the strain gauge by the transient magnetic field produced during discharging process and the measurement precision of the strain gauge was lowered tremendously. According to the theory of Wheatstone bridge, an internal compensation method was proposed in this paper to eliminate the inherent electromagnetic interference. With this method, an compensating gauge was overlapped on top of the working gauge and the both gauges were exposed to the same electromagnetic environment. The electromagnetic interference signals in the compensating gauge and working gauge were offset each other in the bridge circuit. Because there was no mechanical deformation occur on the compensating gauge, only the mechanical effect of the working gauge was tested. Experimental installation of single-stage SICG was set up on the basis of dynamic strain test principles. The stress of the rear part of the armature were measured with dynamic resistance strain gauge. The magnetic-structural coupling analysis of the armature was accomplished with the FEM software and the stress distribution was gained which was matched well with the experimental results.
出处
《测试技术学报》
2010年第4期293-298,共6页
Journal of Test and Measurement Technology
关键词
线圈炮
电枢
应变
内补偿法
应变仪
coilgun
armature
strain
internal compensation method
strain gauge
