Co-authors​ :

 Pierre JOURNOUD , Christophe BOUVET (FRANCE), Bruno CASTANIÉ (FRANCE), Leon RATSIFANDRIHANA (FRANCE) 

An experimental study has been carried out to describe the evolution of the failure load relative to the maximum misalignment angle of curved carbon–epoxy laminates with out-of-plane wrinkle defects for a large range of misalignments [1]. L-angle specimens with different levels of fibre wrinkling were manufactured and tested in four-point bending tests. To manufacture specimens with wrinkles, two geometries of mould were used. A convex mould to produce specimens with limited defects and a concave mould to make samples with wrinkle defects in the radius of curvature. With the concave mould, two hand layup strategies were considered in order to produce specimens with different levels of wrinkles. In the first one, plies were directly stacked in the mould by hand with compaction, enabling parts to be made without defects. The second strategy involved stacking some or all of the layers on a flat surface first and then moving them into the mould. This second method promoted the appearance of wrinkles in the radius of curvature. Digital Image Correlation (DIC) and infrared thermography were used to monitor the tests. They allowed the stress concentrations induced by the wrinkles to be identified, together with their influences on the failure load of the sample. In most cases, increases in wrinkling levels led to decreases in failure loads. Then, a numerical model was developed to take wrinkle and local delamination defects into consideration and assess their impact on the failure load of L-angle specimens under four-point bending tests [2]. Experimental wrinkles based on a previous work were modelled using the Discrete Ply Model strategy and four-point bending simulations were run. The numerical model allowed the effects of each defect (local delamination and wrinkle) to be distinguished and their combined influence on the failure load to be studied with respect to the maximum misalignment.