Research project: Analysis of a Composite Materials using Multi-Scale Computed Tomography Techniques
Currently Active:
Yes
Applications for the use of composite materials are diverse and are often used in the aerospace, automotive and marine industries. Composite materials have complex macro and micromechanical material behaviour, displaying a range of failure modes. In this work multi-scale Computed Tomography (CT) techniques are used to characterise the material structure, from the whole engineering structure geometry down to individual fibre level.
Project Overview
Multi-scale imaging of aerospace
The problem
The failure of composite components is more complex and difficult to design for than in metallic components, as composites are anisotropic and heterogeneous; failure mechanisms depend strongly on loading type, orientation and fibre architecture.
Figures 1 and 2 show the multi-scale structure and inhomogeneity of the materials and some associated damage mechanisms found prior to failure in commercially produced materials.
The ultimate failure of composite laminates is generally determined after a series of interacting events, such as matrix cracking and fibre failures, occurring on a microscopic level. These microscopic processes need to be understood to determine their effect on macroscopic strength.
Multiple damage mechanisms
Solution
Advanced experimental techniques such as multi-scale computed tomography and acoustic emission sensing have been used to analyse the material structure and damage mechanisms of industrially representative composite structures.
The research has provided the first direct in situ measurement of the accumulation of damage for a high performance material under structurally relevant load conditions. [A.E. Scott, M. Mavrogordato, P. Wright, I. Sinclair, S.M. Spearing. In situ fibre fracture measurement in carbon–epoxy laminates using high resolution computed tomography. Composites Science and Technology, Volume 71, Issue 12, Pages 1471-1477, 2011].
A high level of confidence is placed in the measurements, as the failure processes are viewed internally at the relevant micromechanical length-scales, as opposed to previous indirect and/or surface-based methods.
The techniques have provided novel quantitative analysis to inform and validate existing tensile fibre-strength based models.
