REDUCTION IN COMPRESSIVE STRAIN TO FAILURE WITH INCREASING SPECIMEN SIZE IN PIN-ENDED BUCKLING TESTS

Flexural tests were performed on unidirectional T800/924 carbon-fibre/ epoxy composites in a pin-ended buckling rig producing consistent comp ressive failures. Three sets of tests were carried out with all dimens ions geometrically scaled. The results showed a strong decrease in str ain at failure with increasing specimen size. Three further sets of re sts were conducted where the thickness was kept constant and the lengt h and width of the specimens varied. These showed similar strains at f ailure, suggesting that the size effect observed with the scaled speci mens is predominantly due to the reduction in strain gradient with inc reasing specimen thickness. (C) 1997 Elsevier Science Limited.