Carbon fibre lattice strain mapping via microfocus synchrotron X-ray diffraction of a reinforced composite

DOI: 10.1016/j.carbon.2022.08.041

Authors: Jiraphant Srisuriyachot (University of Bath) , Sophie A. M. Mcnair (University of Bath) , Yang Chen (University of Bath) , Thomas Barthelay (University of Bath) , Rob Gray (University of Bath) , Jean Bénézech (University of Bath) , Igor P. Dolbnya (Diamond Light Source) , Richard Butler (University of Bath) , Alexander J. G. Lunt (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Carbon , VOL 194

State: Published (Approved)
Published: August 2022
Diamond Proposal Number(s): 23372

Abstract: Synchrotron X-ray diffraction (SXRD) strain analysis is well established for high crystalline materials such as metals and ceramics, however, previously it has not been used in Carbon Fibre Reinforced Polymer (CFRP) composites due to their complex turbostratic atomic structure. This paper will present the feasibility of using SXRD for fibre orientation and lattice strain mapping inside CFRPs. In particular, it is the first time that the radial and axial strains of carbon fibre crystal planes have been analysed and cross-validated via numerical multi-scale simulation in a two-scale manner. In order to simplify the analysis and provide comparable estimates, an UniDirectional (UD) CFRP formed into a well-established humpback bridge shape was used. The lattice strain estimates obtained from SXRD showed localised stress concentrations and effectively matched the numerical results obtained by modelling. The mean absolute percentage differences between the two were 25.80% and 28.50% in the radial and axial directions, respectively. Differences between the two measurements are believed to originate from the non-uniform thermal history, forming geometry and tool-part interaction which leads to localised residual strains in the laminate which are unable to be fully captured by the numerical simulation performed. The carbon fibre microstructures of the inner plies adjacent to the tool were found to be significantly influenced by these factors and therefore the largest errors were observed at these locations. The approach presented has significant promise and implications for research into the micromechanics of composite materials and areas for future improvement have been outlined.

Journal Keywords: Carbon fibre reinforced polymers; Lattice strain mapping; Fiber orientation; Microstructural characterisation; X-ray diffraction

Subject Areas: Materials, Engineering, Technique Development


Instruments: B16-Test Beamline

Added On: 31/08/2022 10:38

Discipline Tags:

Technique Development - Materials Science Materials Engineering & Processes Materials Science Engineering & Technology Composite Materials Polymer Science

Technical Tags:

Diffraction