Phase contrast micro-tomography and morphological analysis of a short carbon fibre reinforced polyamide

Abstract

Please cite this article as: Cosmi, F., Bernasconi, A., Sodini, N., Phase contrast micro-tomography and morphological analysis of a short carbon fibre reinforced polyamide, Composites Science and Technology (2010), doi: 10.1016/ j.compscitech.2010 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. PHASE CONTRAST MICRO-TOMOGRAPHY AND MORPHOLOGICAL ANALYSIS OF ABSTRACTThe mechanical properties of components made of short fibre reinforced composites, generally obtained by injection moulding, are strongly linked to fibre orientation. Therefore, it is of great importance to be able to verify the results of manufacturing process simulations obtained by commercial software. From the experimental point of view, the definition of carbon short fibre structure within a polymeric matrix in a micro-tomography is a non-trivial task, as the X-rays absorption properties of the two phases are very similar. This paper presents how this problem was overcome by using phase contrast imaging techniques. High resolution fibre structure reconstructions could therefore be obtained. The reconstruction of a large sample volume by overlapping of successive tomographies was also discussed. Moreover, this work shows that the anisotropy identification techniques based on morphological parameters, previously introduced by some of the Authors for short glass fibre 2 reinforced polymers, can also be adopted for fibre arrangement identification in this type of materials.

Threshold Identification for Micro‐Tomographic Damage Characterisation in a Short‐Fibre‐Reinforced Polymer

“…The cross‐sections (slices) of the sample structure were reconstructed from the angular projections by means of the STPv4.04 software, developed in house at Elettra. A 3D representation of the internal structure of the short fibres within reinforced polyamide samples can then be obtained by stacking the slices and can be used as a starting point for morphological and structural investigations .…”

“…In order to be able to compare the two tomographic scans (Tomo_1 and Tomo_2) of the same sample, an accurate identification of the homologous volumes required some degree of attention and was performed manually by exploiting the presence of clearly recognisable fibre aggregations, similarly to . The relative position of the slices in the two reconstructions was checked every 50 slices (0.1100 mm).…”

“…Numerous methods have been proposed in literature in order to describe the morphological properties of a two‐phase material. The Mean Intercept Length, MIL, is a global method that has been successfully applied to describe the fibre orientation in SFRP from micro‐CT scans . The MIL is computed by superimposing a grid of parallel lines in several 3D directions to the image of the reconstructed volume and by dividing the length of the grid by the number of transitions in a same phase .…”

Sequential kriging‐based closure approximations for flow‐induced fiber orientation and prediction of composite stiffness

“…As a result, knowing the flow induced fiber orientation is of great importance because the fiber orientation state significantly affects the composite mechanical properties. Accordingly, accurate and efficient predictions of the fiber orientation are challenging tasks and have been investigated for many years owing to their industrial applications .…”

Phase retrieval in in-line x-ray phase contrast imaging based on total variation minimization

“…X-ray PCI found applications in materials science, ranging from investigating the microstructure of carbon-based materials [1,2] to in-situ measurements of dynamic processes taking place in metal alloys and semiconductors [3][4][5]. X-ray PCI is also entering the field of pre-clinical biomedical research, namely, small animal imaging and various ex-vivo/in-vitro studies [6][7][8][9][10][11].…”