Development of "Dynamic Crack Microscope"

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A high sensitivity and low noise integrated acoustic emission sensor has been successfully developed to detect microcrack. This sensor is designed by both the piezoelectric element vibration mode and the electric circuit of first stage amplifier which minimizes by eliminating the signal loss and noise. This sensor is sold from the cooperative company of this project.AE data acquisition and analysis system have been also successfully developed. The high speed data acquisition system consists of the analog to digital converter (8bit/20MHz/6ch), the multi processing digital signal processors of each AE channel, the pipe line signal processing using digital signal processor for AE source location and the host personal computer (80386SX/80387SX) to display and analyze data. The system capability is as follows : the data acquisition speed with 6ch is 70 events/sec, the maximum number of storage events are 7000, the resolution of source location is a few hundred micron meter, the calculation time of source characterization is less than one second each event. This system will be on sale from the cooperative company as "Dynamic Crack Microscope".Preliminary AE tests were carried out for ceramic materials and this Dynamic Crack Microscope has demonstrated great potential for the investigation of fracture mode of each micro crack and fracture mechanism in the fiber reinforced composite materials.