Abstract
Acoustic emission (AE) from composite materials during tensile test have been studied in order to investigate the fracture process at cryogenic temperatures. Commercially available glass cloth reinforced plastics (epoxy) has been chosen and tested at room (RT), liquid nitrogen (LNT) and liquid helium temperature (LHeT). Specimen was loaded in tensile mode and AE was simultaneously detected by PZT sensor of which resonance frequency was 140kHz. The AE counts at cryogenic temperatures were large compared with those at RT. The decrease of temperature bring the shift of the point, at which AE count showed rapid rise, to lower strain level. The temperature decrease also brought the increase of AE intensity. different types of AE signals were found in different fracture modes. It was confirmed that the identification of fracture mode of composite materials was possible in terms of AE analysis referring stress-strain curves.
