节点文献
一种新型无损检测仪的研制
A New Design for NDT Device
【作者】 彭道坚；
【导师】 修吉平；
【作者基本信息】 华中科技大学 ， 材料加工工程， 2007， 硕士
【摘要】 本文介绍的新型无损检测仪是一种以磁致伸缩为原理工作的新型检测仪表,它应用于各种钢管的无损检测。本文详尽阐述了这个仪器的研制。该仪器采用分体式设计,选用WINBOND公司的W78E58B单片机作为处理器。仪器分为激励和检测两大部分:激励部分的作用是发射1到8个频率为5K到250K的脉冲,脉冲的电压值为200V、400V、600V、800V、1000V五挡可变,功率最大可以达到4千瓦。我们结合单片机技术和高频电路设计技术,设计出了一种全新的脉冲发射电路,它很好的改善了脉冲波形。检测部分中最重要的是信号的滤波处理,它所要检测的是前面发射脉冲所反射的机械波,这个机械波是一个干扰很大的弱信号,我们采用美信公司所生产的集成滤波芯片MAX275对这个信号进行滤波放大,再用数据采集卡DSO-220 USB进行信号采集,采集上来的信号传到PC机进行处理。通过PC机显示的波形可以判断所检测钢管的缺陷。该仪器通过RS-232串行通信接口与计算机连接进行数据传输,计算机可以实时的读取测量的数据并修改发射脉冲的参数。本文分章节详细的阐述了仪器的研制过程,首先是仪器的原理和总体规划,然后是两大功能模块的的软、硬件设计和调试,本文对串行通信协议也作了详细的说明,最后是文章的总结。
【Abstract】 In this article, the study of a new NDT-device based on magnetostrictive effect is expatiated in detailed, and it can realize the NDT of all kinds of steel pipe. The microchip W78E58B of Winbond Co. is adopted as MCU in this device. It includes two important parts such as the system of exciting and receiving. The function of the exciting-part in the device is transmitting one to eight pulses which frequency is 5Khz to 250Khz. The voltage of the pulse is alterable from five chances (200V、400V、600V、800V、1000V). In this paper, a new high voltage transmitting circuit is given combining with microchip and high frequency circuit design technology. It can improve transmitted and received obviously, then enhance the measuring precision and anti-jamming capability. The receiving-part must detect a very weak signal with much stronger disturbing signal. I select the Integrated-Filter(MAX275) made from MAXIM to filter and magnify the signal, and then collect the signal with the Data- Acquisition-Card (DSO-220 USB) and transmit to computer via USB. In addition, the data is transmitted to computer by an isolated RS-232 interface, and computer can read Detecting-Data and modify the parameter of the pulse. The paper describes the design course of the device in chapter: chapter 1 describes the theory and history of NDT, the layout of instrument is given in chapter2, and then describe the design of software and hardware of the device in detail, chapter 6 and 7 introduces the serial communication protocol and the instrument, the last chapter is the summarize.