Submitted Abstract
Polymer composites provide a unique solution to combine structural strength and low weight. To produce these materials at an affordable cost, a new family of fabrication techniques known as Liquid Composite Molding (LCM) emerged in recent years. This technology consists of injecting the polymer resin through fibrous reinforcements contained in a mold. It was used for the new Leap aircraft engine made of composites reinforced by 3D textiles (Safran, 2017). The art of composite manufacturing involves various engineering fields and requires combining sophisticated experimental characterisation techniques such as micro-tomography with advanced computer simulation. The proposed mobility project offers a unique opportunity of setting up such a joint effort between the SUSMAT research unit of the Materials Research and Technology (MRT) Department of LIST and the Chair on composites of high performance (CCHP) of Polytechnique Montréal directed by Prof. François Trochu. The goals of the project are twofold: (1) investigate quality control and manufacturing issues for high performance composites made by LCM using micro-tomographic analysis and process modelling; (2) assist the National Composite Center of Luxembourg (NCC-L) in developing its research capability in LCM. As demonstrated by the research team of Prof. Trochu (Madra, 2017), micro-tomography provides a unique tool to better understand the composite microstructure and its evolution during processing. The microstructure governs mechanical properties and fatigue behaviour. Two computer tools will be used and validated: (1) transfer of a standard geometric computer model of textile architecture in voxel format; (2) from the voxel description obtained by micro-tomography, construct an analytic model of the composite microstructure based on dual kriging (Trochu, 1993). This statistical computer method not only allows a significant reduction of the amount of data required to describe the microstructure, but provides also a unique way to model its statistical variability. This latter point is of paramount importance in composites because of the inevitable scatter in mechanical properties that arises from the microstructural variability. The first computer procedure known as “voxelisation” is required to model the microstructure and simulate its reorganisation under compaction. The second procedure provides a description based on dual kriging of the actual fibrous reinforcement that allows simulating the resin flow and the creation and transport of voids during mold filling. SUSMAT and the research group Design and Durability for Composites (DURACOMP), headed by Dr Belouettar, will provide a key contribution in process modelling. Prof. Trochu will provide a unique expertise to LIST thanks to 30 years of practical experience in applied research on composite manufacturing by resin injection, after developing the commercial software PAM-RTM to simulate the Resin Transfer Molding (RTM) process (ESI, 2017) (www.esi-group.com) and directing three research chairs at Polytechnique Montreal, one sponsored by the prestigious Canada Research Chair programme, one by General Motors in the automotive field and one by Safran in aerospace.