Characteristics of an acoustic emission source from a thermal crack in glass

✍ Scribed by Kwang Yul Kim; Wolfgang Sachse

• Publisher: Springer Netherlands
• Year: 1986
• Tongue: English
• Weight: 918 KB
• Volume: 31
• Category: Article
• ISSN: 1573-2673
• DOI: 10.1007/bf00018928

✦ Synopsis

Thermal cracks of mode I type oriented normal to the surface along an initial scratch were generated by blowing cold nitrogen gas through a small nozzle onto the surface of a glass plate. Acoustic emission (AE) signals emitted from the thermal cracks were detected on the opposite side of the plate, both at epicentral and at off-epicentral positions with a nine-channel AE system. AE source characteristics, such as moment tensor components, source-time function, radiation pattern, and dipole strength, were obtained from the detected waveforms. The strength of dipoles associated with the thermal cracks was determined from comparing the crack signals to those generated when a glass capillary was broken at the crack site prior to crack formation. It is shown that the AE source-time function, together with the dipole strength, can provide valuable information on the dynamic behavior of fracture.