Synchrotron radiation computed laminography for polymer composite failure studies

Feng Xu,Ian Sinclair,Tilo Baumbach,Andrew J Moffat,Lukas Helfen,Gregory Johnson

doi:10.1107/s0909049510001512

Abstract

Synchrotron radiation computed laminography is applied to the three-dimensional micro-imaging of damage in large polymer composite plates with high spatial resolution. The influence of different experimental conditions is studied with respect to measurement time optimization, dose minimization and reduction of artefacts in the reconstructed images. Failures like delaminations, transverse ply cracks and splits are observed under in situ loads. The propagation of up to 2 mm-long cracks is non-destructively followed in situ and investigated in detail. By phase retrieval using a single detector distance, the failures can be easily visualized in three dimensions.

Highlights

Computed laminography (CL) using synchrotron radiation (SR) has been developed as a non-destructive three-dimensional (3D) imaging method for flat specimens (Helfen et al, 2005)
Qualitative and quantitative phasecontrast imaging becomes possible (Nugent et al, 1996; Cloetens et al, 1999, 2002; Paganin et al, 2002) which has been extensively shown in computed tomography (CT), a 3D imaging technique nowadays well established at synchrotron imaging set-ups
We demonstrate that laminographic imaging with SR is a promising technique to study failures in carbon composite materials which allows us to follow the damage evolution for increasing loading states

Summary

Introduction

Computed laminography (CL) using synchrotron radiation (SR) has been developed as a non-destructive three-dimensional (3D) imaging method for flat specimens (Helfen et al, 2005). Otherwise, when a laterally extended object strongly exceeds the lateral field of view of the detector (as is typically the case for conventional structural testing coupons), CT suffers from exceedingly high absorption (and resulting artefacts from insufficient transmission) when the plate-like object is near to parallel to the beam direction. To avoid this results in a destructive method since a specimen with the ROI containing the damage structure has to be extracted from a mechanically representative loading state. The application to micro-imaging of the formation and propagation of damage in a 70 Â 60 Â 1 mm polymer composite panel under different in situ loads demonstrates the potential of the method in materials science

Method and samples

Results and discussion

Conclusions

46. Berlin