University of Manchester

Understanding the fatigue damage mechanisms in 3D woven composites

Dominic Stratton
Active

Scientific Case

3D woven composites have gained popularity recently due to improved performance in the through-thickness direction under static loading than that of 2D composites. However, the fatigue properties of 3D woven composites have yet to be validated. The aim of this project is to further explore the fatigue damage mechanisms of 3D orthogonal woven CFRPs under tension-tension fatigue loading at different stress levels. The failure mechanism will be characterised by X-ray computed tomography (X-ray CT) and this data will be supported by optical microscopy of the specimens after failure. A further project aim is to quantify how the size and the distribution of macro voids in a composite sample effects its fatigue crack propagation.
Composites

Experiment Design

The region-of-interest in both specimens is 24mm x 16mm x 3mm. However, it could be possible to reduce this to improve image quality. The aim of this project is to image the cracks caused by the fatigue testing to understand how they lead to failure. Specimens will be removed from the mechanical testing frame after certain number of fatigue cycles and mounted on sample stage in CT scanner for image acquisition. The scanner to be used is the Nikon XTH 225 and the expected voxel size is around 7 μm.
Scanners and Rigs
Nikon XTH225
3
Not Required
2

Sample & Safety

The material studied is carbon fibre reinforced polymer matrix composite. Two types of specimen geometry were used for fatigue test at different load levels. Specimen one test-piece is 130mm x 16mm x 3mm. Specimen two test-piece is 64mm x 16mm x 3mm. The region of interest in both specimens is 24mm x 16mm x 3mm
2
Low Hazard

Scan Records

Project Report