(此文档为word格式，下载后您可任意编辑修改！)摘要钢管在生产和加工的过程中，其内部或者外部会产生分层、裂纹等各种缺陷。

目前比较广泛的一种无损检测方法是超声波探伤，它可以在不损伤被检测对象的内部结构的前提下进行检测。

论文以超声探伤理论为基础，利用CPLD强大的逻辑处理功能结合单片机MCU作为系统的核心开发了超声检测系统。

在论文设计的过程中，采用了模块化的设计方案，提高了系统的可靠性；在主控芯片上选择了低成本的单片机MCU和可编程逻辑控制器件CPLD,提高了系统开发的灵活性。

在设计中首先对超声波检测技术进行介绍，并对超声波检测的基本理论进行探讨。

对设计中的数字式超声波探伤仪的总体设计及各功能模块进行探讨，之后重点研究超声检测系统的硬件设计，包括超声波的激励电路，信号处理模块，MCU模块以及数据采集处理系统的设计。

最后利用LabVIEW对超声检测系统进行软件设计，并进行总体流程的设计及下位机的设计。

关键词超声波探伤虚拟仪器CPLD单片机AbstractIn the production and processing of iron and steel materials,its internal and external will produce a layered,cracks and other defects.The relatively wide range of a nondestructive testing method is ultrasonic flaw detection that can not damage the object to be detected in the internal structure of the premise of testing with the basis of the ultrasonic flaw detection theory,the CPLD and MCU are the core of system development of ultrasonic testing system.In the process,to design it use a modular design to improve the reliability of the system;and select low cost MCU single-chip microcomputer and programmable logic control device CPLD in the main control chip to enhance the system flexibility.In the paper, the ultrasonic detection technique is introduced,and then the basic theory of ultrasonic testing id discussed.Then the design of the digital ultrasonic flaw detector in the general design and the functional module is discussed,then focuses on the hardware design of ultrasonic detection system,including the ultrasonic transmitting circuit,receiving circuit,MCU module and data acquisition and processing system design.Finally using LabVIEW on ultrasonic detection system for the software design,the system software design of the overall process,ultrasonic excitation pulse signal generating,data acquisition system control logic in this paper.Key words Ultrasonicexamination VirtualInstrument CPLD MCU目录摘要 (I)Abstract ...................................................................................................................................................... I I 第1章绪论. (1)1.1 课题背景 (1)1.2 超声波的概念和方法 (1)1.2.1 超声波检测技术 (2)1.2.2 超声无损检测的发展趋势 (2)1.2.3 国内外发展状况 (3)1.3 虚拟仪器的发展 (4)1.3.1 虚拟仪器的概念 (4)1.3.2 虚拟仪器的优点 (4)1.4 本设计研究内容及研究意义 (5)第2章超声波及超声波检测的原理 (6)2.1 超声波 (6)2.1.1 超声波的分类 (6)2.1.2 超声波的传播衰减 (7)2.1.3 超声波的速度及波长 (7)2.1.4 超声波探伤的原理 (8)2.2 探头的选择及缺陷的定位 (10)2.2.1 探头 (10)2.2.2 探头频率的选择 (10)2.2.3 判断缺陷的存在 (11)2.2.4 缺陷的定位 (12)第3章系统硬件设计 (15)3.1 超声波检测系统总体设计 (15)3.2 超声激励电路 (16)3.3 信号采集电路 (17)3.3.1 限幅保护电路 (17)3.3.2 放大电路 (18)3.3.3 滤波电路 (18)3.3.4 检波电路 (21)3.3.5 A/D转换电路及数据存储电路 (21)3.4 单片机及CPLD电路 (22)3.5 其他电路的设计 (24)3.5.1 光电耦合电路 (24)3.5.2 电源电路 (25)3.5.3 通讯接口电路 (26)第4章系统软件设计 (28)4.1 LabVIEW的程序结构 (28)4.2 上位机软件设计 (28)4.3 下位机软件部分设计 (29)4.3.1 数据采集 (31)4.3.2 CPLD的程序设计 (31)4.3.3 MCU的程序设计 (32)结论 (34)致谢 (35)参考文献 (36)CONTENTSAbstract(Chinese) (I)Abstract..................................................................................................................................................... I I Chapter 1 Introduction. (1)1.1 Project background (1)1.2 The concept and method of ultrasonic (1)1.2.1 Ultrasonic testing technology (2)1.2.2 Development trends of ultrasonic testing (2)1.2.3 The domestic and foreign development condition (3)1.3 Virtual instrument development (4)1.3.1 The concept of virtual instrument (4)1.3.2 The advantages of virtual instrument (4)1.4 This topic research significance and the research content (5)Chapter 2 Ultrasonic and ultrasonic detection principle (6)2.1 Ultrasonic wave (6)2.1.1 Ultrasonic classification (6)2.1.2 Ultrasonic transmission attenuation (7)2.1.3 Ultrasonic velocity and wavelength (7)2.1.4 The princeple of ultrasonic flaw detection (8)2.2 Probe selection and location of defects (10)2.2.1 Probe (10)2.2.2 Probe frequency selection (10)2.2.3 Judging the defects (11)2.2.4 Defect location (12)Chapter 3 System hardware design (15)3.1 Ultrasonic detection system design (15)3.2 Ultrasonic excitation circuit (16)3.3 Signal acquisition circuit (17)3.3.1 Limiting protection circuit (17)3.3.2 Amplifying circuit (18)3.3.3 Filter circuit (18)3.3.4 Detection circuit (21)3.3.5 The A/D converting circuit and a data storage circuit (21)3.4 Single chip MCU and CPLD circuit (22)3.5 The other circuit design (24)3.5.1 A photoelectric coupling circuit (24)3.5.2 Power supply circuit (25)3.5.3 Communication interface circuit (26)Chapter 4 System software design (28)4.1 Virtual instrument system and construction method (28)4.2 The front panel and the sampling procedure (28)4.3 The overall process of system hardware (29)4.3.1 Data acquisition (31)4.3.2 CPLD program design (31)4.3.3 MCU program design (32)Conclusions (34)Acknowledgements (35)Appendix (36)第1章绪论1.1课题背景随着我国现代化工业的飞速发展，高质量的材料是其重要的保障。