Advanced 3D ultrasonic characterisation of 2D woven composites

Maybury, Laura

Abstract

The principal aim of this project was to generate an automated mapping programme that will identify and quantify deviations from design, due to either manufacturing processes or in-service defects. Focusing on woven carbon fibre composites, using data acquired from ultrasonic non-destructive testing, individual weave identities have been developed. Knowledge of the individual weave identity will enable two key pieces of information when analysing components; lay-up and the presence of defects in terms of shear and rotation. Knowledge of the lay-up and presence of defects results in better informed decisions regarding the manufacture and the longevity of components. In many cases the requirement for a twin component to be manufactured will be negated; subsequently saving both time and money.

The development of individual weave identities, alongside automation of the classification procedure is the key contribution of this thesis. The literature review shows that this capability does not currently exist. The weave identity work began with the adaption of Miller Indices from crystallography. In order to automate the weave identification, a spatial frequency vs. angle plot was established using image transformation. It was the realisation that the weave characteristic lines (and their subsequent spots on the spatial frequency vs. angle plots) are different from the lines corresponding to the fibre’s warp and weft tows which allowed for the discrimination of weave type. The process of weave identification was automated and both the accuracy and precision of the measurement of in-plane were established. Consequently, the developed technique enables the identification of angular distortions in woven carbon fibre composites. Finally, the testing of real samples showed that the presented method of weave classification works well, providing the images of the weaves are good, and that the imaging of the weave gets worse with depth, surface roughness and when the probe frequency does not match the ply resonance.

Citation

Maybury, L. Advanced 3D ultrasonic characterisation of 2D woven composites. (Thesis). University of the West of England. Retrieved from https://uwe-repository.worktribe.com/output/3292378

• Thesis Type: Thesis
• Deposit Date: Jun 16, 2020
• Publicly Available Date: Jul 3, 2020
• Public URL: https://uwe-repository.worktribe.com/output/3292378
• Award Date: Jul 3, 2020