The process-induced distortions of asymmetric composite laminates have been the focus of many studies to date, given their ‘unpredictable’ nature on reaching room temperature, generating either a ‘saddle’ or cylinder shape and reaching varied degrees of curvature. Models have been devised and developed using classical laminate theory extensions to predict the room temperature shapes and curvatures with greater accuracy. However, because these shape deviations and curvature are shown to be dependent on many factors, (including laminate size, stacking arrangement, thickness, thermal history and constituent properties) a vast range of studies prove incomparable to one another, and exclude noted ageing and environmental effects. The aim of this study was to identify the factors controlling curvature generation in asymmetric carbon fibre laminates in order to quantitatively describe their behaviour. The curvature generation of several cross-ply asymmetric epoxy/carbon fibre composite laminates has been studied by way of composite manufacture (using manual lay-up and vacuum bagging technique) in order to identify the dominant factors controlling curvature, including shrinkage during curing, CTE mismatch and geometry. Measured curvatures were compared to developed theoretical models under a series of interfacial conditions; taking into account the slippage between plies during laminate cure, unaccounted for in previous work. The causes of any deviation between theoretical and experimentally achieved curvatures have been determined and attributed to a number of microstructural defects such as delamination, voiding and, in addition, the degree of cure achieved.
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