Multi-scale modelling of non-uniform consolidation of uncured toughened unidirectional prepregs

G. Sorba*, C. Binetruy, E. Syerko, A. Leygue, S. Comas-Cardona, J. P.H. Belnoue, O. J. Nixon-Pearson, D. S. Ivanov, S. R. Hallett, S. G. Advani

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

Abstract

Consolidation is a crucial step in manufacturing of composite parts with prepregs because its role is to eliminate inter-and intra-ply gaps and porosity. Some thermoset prepreg systems are toughened with thermoplastic particles. Depending on their size, thermoplastic particles can be either located in between plies or distributed within the inter-fibre regions. When subjected to transverse compaction, resin will bleed out of low-viscosity unidirectional prepregs along the fibre direction, whereas one would expect transverse squeeze flow to dominate for higher viscosity prepregs. Recent experimental work showed that the consolidation of uncured toughened prepregs involves complex flow and deformation mechanisms where both bleeding and squeeze flow patterns are observed [1]. Micrographs of compacted and cured samples confirm these features as shown in Fig.1. A phenomenological model was proposed [2] where bleeding flow and squeeze flow are combined. A criterion for the transition from shear flow to resin bleeding was also proposed. However, the micrographs also reveal a resin rich layer between plies which may be contributing to the complex flow mechanisms during the consolidation process. In an effort to provide additional insight into these complex mechanisms, this work focuses on the 3D numerical modelling of the compaction of uncured toughened prepregs in the cross-ply configuration described in [1]. A transversely isotropic fluid model is used to describe the flow behaviour of the plies coupled with interplay resin flow of an isotropic fluid. The multi-scale flow model used is based on [3, 4]. A numerical parametric study is carried out where the resin viscosity, permeability and inter-ply thickness are varied to identify the role of important variables. The squeezing flow and the bleeding flow are compared for a range of process parameters to investigate the coupling and competition between the two flow mechanisms. Figure 4 shows the predicted displacement of the sample edge with the multi-scale compaction model after one time step [3]. The ply distortion and resin flow observed in Fig.1 is qualitatively retrieved by the computational model.

Original languageEnglish
Title of host publicationProceedings of the 21st International ESAFORM Conference on Material Forming, ESAFORM 2018
PublisherAmerican Institute of Physics (AIP)
Volume1960
ISBN (Electronic)9780735416635
DOIs
Publication statusPublished - 2 May 2018
Event21st International ESAFORM Conference on Material Forming, ESAFORM 2018 - Palermo, Italy
Duration: 23 Apr 201825 Apr 2018

Conference

Conference21st International ESAFORM Conference on Material Forming, ESAFORM 2018
CountryItaly
CityPalermo
Period23/04/1825/04/18

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