复杂断面重轨在线无损检测系统设计___涡流无损检测部分.doc

毕业设计说明书（毕业论文） 题 目：复杂断面重轨在线无损检测系统设计 ——涡流无损检测部分 复杂断面重轨在线无损检测系统设计 ——涡流无损检测部分 摘 要 论文首先分析了裂纹检测的几种方案，结合铁道设施结构特点、运营环境，对这几种方案进行了对比，从而确定了采用便携式涡流检测仪进行探伤。接着介绍了涡流检测原理，基于电磁场理论推导了相关的重要公式。阐述了阻抗分析法，并用其分析了影响检测线圈阻抗变化的几个因素。推导了放置式探头线圈的特征频率，为检测频率的选择提供了参考。 在传感器设计中，本文在分析和借鉴现有一些性能较好的探头所采用的结构形式的基础上，通过实验反复修正，得到一种高性能的传感器。并通过大量实验分析确定了各因素对传感器一些性能的影响，为探头线圈尺寸提供了优化。最后采用正交试验设计方法选定了各参数的合理组合，完成了传感器的总体设计。 在硬件设计方面：为了提高灵敏度，通过数学推导传感器信号变换电路中的各个参数，给出了各参数的求取公式，并给出了检测系统激励源、信号调理、单片机系统、显示报警等模块的硬件设计。在软件设计方面：采用模块化软件设计方法，分析了每一个模块的程序流程图，并进行了软件设计。 关键词：无损检测；涡流检测；裂纹缺陷；数据采集；信号处理 the Design of Online Nondestructive Testing System of Complex Cross-section Heavy Rail ——Turbulent flow non-destructive inspection part Abstract Firstly, several method of testing crack defect are put forward and compared. Considering of configuration and using characteristic crack, we get the result that the crack defect can be only detected by portable testing instrument. Secondly,the pinciple of eddy current test is introduced.Based on electromagnetic field theory,some important formulas are deduced. Impedance analytical method is presented,through which we analyze some factors that alter testing coil impedance’s value. Then,characteristic frequency of laid test coil is calculated, it is important to select the test frequency. As for the sensor design, a sensor with high performance is designed through modification based on some sensors with better performance. Various factors that influence the sensor performance are analyzed through experiment to optimize the size of coil. Finally used the orthogonal experiment design method, we designed the parameters with reasonable combination, and conpleted the design of sensor system. As for hardware design, in signal converter, in order to improve the sensitivity,the parameter of signal converter is gotten though math illation. Excitation circuit,signal converter circuit, single chip system, demonstration, and alarm part are all given partcular annlysis and design. As for software design, the