Research On Lamb Wave Tomography System

Lamb wave tomography is a new detection method in the area of lossless detection, and has been wildly used in the healthy and lossless detection of material, precise and large-scale machines, building structures. It works immensely in the improvement of product quality and strength of product security, with the development of society and science and technology, digital logic circuit of VLSI circuit has been an indispensable part of lossless detection.Lamb wave tomography is a new technology area and has been developing since decades ago. In this thesis, some exploratory research has been done in this system. After finding out in detail physical properties of lamb wave, artificial circuit and digital circuit, a construction proposal of lamb wave tomography system hardware platform is designed in the support of advanced FPGA technology.The key ideal of the whole system is including PCB logical controlling core, signal generation, PCB launch and high-speed data collection PCB. PCB logical controlling core carries the core chips FPGA of the whole system, and it implements digital frequency compound, high-speed storage, USB 2.0 high-speed digital communication and so on. Signal generation and launch PCB is to make the generated signal analog, drive with frequency amplification PCB and then launch stimulated ultrasonic wave into the structure to form lamb wave. The functions of high-speed collection PCB are preprocessing of echo signal. A/D transformation and then transporting collected digital signals in the way of LVDS into FPGA. In this whole system, except amplification and filtering circuit, all other functions are controlled or directly achieved by FPGA, which for the purpose of making design plan diverse and flexible.