Gaining mechanistic insight into key factors contributing to crack path transition in particle toughened carbon fibre reinforced polymer composites using 3D X-ray computed tomography

Abstract

Composite materials are increasingly used to help in reducing the carbon footprint of transportation and upscaling renewable energy infrastructure that provides clean energy for future cities. However, the inherent susceptibility of carbon fibre reinforced polymers to impact damage results in knock-down in design and is linked to the micro-mechanistic response of the material to damage. In situ experimental and high-resolution imaging techniques using X-ray computed tomography (X-ray CT) have been used to gain a mechanistic understanding of the key factors controlling crack path — and hence macro-scale toughness within a composite. Multiscale Synchrotron Radiation Computed Tomography (SRCT) and lab-based micro-focus X-ray CT are used to investigate different material systems toughness response from standard Double Cantilever Beam tests. The crack transition to the weaker ply region of the composite is identified as a controlling factor across a scale of mm’s, and ‘trigger’ regions are reported on and investigated. The ‘trigger’ regions were identified as gaps in the ply adjacent to the interlayer. This work feeds directly into delamination growth predictions, a better understanding of material response, and enabling informed manufacture and design, allowing for reduced material usage, longer life and more sustainable vehicles and infrastructure.

Keywords

• Transport
• Renewable energy
• Polymer matrix composites
• Synchrotron Radiation Computed Tomography
• X-ray computed tomography
• Delamination