Effect Of Fiber Microstructure On Kinking In Unidirectional Carbon Fiber Reinforced Composites Imaged In Real Time Under Axial Compression

It is well known that fibre-reinforced polymer composites (FRPs) undergo micro buckling, then catastrophic failure by kinking when loaded under compression. The aim of this project is to use x-ray computed tomography (CT) to investigate how initial fibre misalignment impacts initiation and propagation of FRP kink bands. We manufactured glass fibre/epoxy composites with intentional fibre misalignment and waviness. The misalignment angle, amplitude, and phase of the waviness are quantified algorithmically from SEM images and CT scans. This step is followed by in-situ compression captured at the European Synchrotron Radiation Facility’s ID19 beamline. Previous work has shown that kinking occurs within 1.2 ms [1] and is essentially planar [2]. As such, synchrotron radiography at 40 kHz is necessary to capture the kink event while achieving the high spatial resolution needed for tracking fibre trajectories. We will focus on the contribution of in-plane waviness on damage within the kink plane, as well as the role of both in-plane and out-of-plane waviness on damage propagation in 3D.