INTERLAMINAR SHEAR-STRENGTH OF HIGH-DENSITY LAMINATES AT CRYOGENIC TEMPERATURES

Glass-fibre-reinforced plastics with 73 vol% glass content have been d eveloped with improved mechanical and thermal properties in the lamina ted direction. The thermal contraction down to liquid-helium temperatu re and the Young's modulus at room temperature in the laminated direct ion were 0.3% and 23 GPa, respectively. The interlaminar shear strengt h (ILSS) measured by the short-beam shear method at liquid-nitrogen te mperature was confirmed not to decrease with increasing glass content. The change in ILSS induced by electron irradiation was also studied. Approximately a 50% decrease in ILSS was brought about by 20 MGy irrad iation. The applicability of the material for large-scale superconduct ing magnets is discussed.