钢筋混凝土保护层厚度的无损检测方法的研究-电气工程专业论文.docxVIP

钢筋混凝土保护层厚度的无损检测方法的研究 钢筋混凝土保护层厚度的无损检测方法的研究 RESEARCH ON NONDESTRUCTIVE TESTING METHODS OF CONCRETE COVER THICKNESS IN REINFORCED CONCRETE STRUCTURE ABSTRACT With the development and perfection of electromagnetic theory and experiment, it promotes the continuous development of the nondestructive testing and evaluation. The pulsed eddy current (PEC) non-destructive testing technology is a new branch of the eddy current nondestructive testing. Comparing with the conventional single-frequency eddy current technology, the pulsed eddy current contains more information in its response signal because of its wider frequency spectrum. We applies it to detect the concrete cover thickness of steel concrete, and good results have been achieved. In this paper, the recent research advances of research institute in China, abroad are reviewed in the engineering application and defect recognition with PEC. The working principle and the equivalent circuit of PEC transducer is elaborated, and given the relationship between detection distance and coil impedance. Theoretically, we analyze the relationship between the intensity of eddy current in coil and detection distance and between the intensity of eddy current in coil and input frequency. The characteristics signal with noise is acquired from the experiment device. According to the signal features, we design corresponding signal regulate circuit. With high precision of the A/D C8051F350 microcontroller as control core, we make more accurate testing results. Finally, through the experiment, the influence of the excitation pulse frequency and duty ratio on the pulsed eddy current testing system were analysed. We analyze the collected data and find the close relationship between difference of area from the inductive voltage signal and detection distance. The test proves the feasibility of PEC testing technology in testing concrete cover thickness. KEY WORDS：pulsed eddy current testing, concrete cover thickness, c8051f350 microcontroller,