Pocket Type Ultrasonic Flaw Detector Design

Ultrasonic detecting technique is a very important method in the field of nondestructive testing, which has been widely used in on-line quality control, safety testing of in-service equipment and key parts. Digitalization of ultrasonic testing has become an inevitable trend of testing instrument development.Based on the fundamental principles of reflective ultrasonic flaw detecting, this dissertation developed a digitalized pocket type ultrasonic detectors control system with FPGA, thus effectively overcoming the drawbacks of traditional system with merely a simple core of single chip processor, and meeting the requirements of digitalized ultrasonic flaw detecting instruments such as hardware and software field programmability, high reliability, low power cost, high privacy and small volume and weight.Afterwards, this thesis has designed ultrasonic sending and receiving circuit and edited digital control module basing on FPGA, thus realizing logic functions such as ultrasonic wave emitting, timing frequency dividing, data acquisition, and liquid crystal display. Data acquisition and storage system is designed in this thesis to preserve the results which are for further analysis by upper machine. In order to accurately judge the existence of defects, the depth of the defect visually to make the man-machine interface more human and convenient, LCD display module is also designed which directly indicates the actual effect of flaw detection.In this dissertation ultrasonic testing technology and ultrasonic flaw detectors development are firstly introduced, following the basic theory of ultrasonic detection, with stress on principle of pulse reflecting type ultrasonic detectors afterwards. Then the overall design of the pocket type ultrasonic detectors and each function module are discussed, and the solution scheme of ultrasonic flaw detector is determined. After research of hardware design of digital pocket ultrasonic flaw detector system, digital control part of the instrument is highlighted. Finally the whole design is validated in experimentation.