MACRO-INSTABILITY OF UNIDIRECTIONAL CFRP COMPRESSION TEST SPECIMENS

With most common compression test methods, unidirectional carbon-fibre -reinforced plastic fails at such low stresses that specimens are unli kely to buckle. However, when the test method is improved and strains approach 2% it is important that the onset of buckling is recognised, and predicted. The current paper presents experimental data which are compared with predictions from a modified buckling theory. It is shown that shear deformation and varying modulus of elasticity should be in cluded in the predictive method. When reasonable assumptions are made concerning the support conditions at the specimen ends, predictions ag reed well with experimental data obtained for the particular material (XAS/914) studied here.