Collaborative test programme results for 0° tensile properties on carbon-epoxy AS4/8552 and carboncyanate M55J/954-3 composite materials and some considerations on EN 2561 test standard

A collaborative test programme has been undertaken on modified epoxy matrix 8552 reinforced with AS4 carbon fibres, and cyanate 954-3 reinforced with M55J high modulus carbon fibre, both in the form of unidirectional prepreg. To date more than 300 spccimens have been tested according to the EN 2561 standard (tensile test parallel to the fibre direction). Different testing conditions such as tabbed and untabbed specimens, dry and wet conditioning, 23 and 70(degree)C test temperature, 7° bevelled or squared off 90(degree) tabs, and the influence of different gripping systems (mechanical and hydraulic) were studied. Average strength values and Youngʹs modulus values are presented with their standard deviations for these materials at every tested condition. In tensile strength measurements, the importance of using tabs for the gripping system and tested material is demonstrated.