LCM of thermoset-based fiber reinforced composites for large-scale applications: are process kinetics and structural properties antagonistic?

This article reviews the main methods to manufacture large-scale composite parts, with a focus on Liquid Composite Molding techniques of thermoset-based fiber reinforced structural parts. As this process relies on the impregnation of a dry textile stack, this manufacturing step is crucial in terms of part production rate, and part quality. To increase the process kinetics, a large effort has been devoted to increase the permeability of the textile preforms, while keeping a similar fiber content. An increase of almost two orders of magnitude can be attained if the textile shows a strong separation of scales between densely packed tows and large intra-two spaces. This however leads to a potential degradation in the resulting structural properties, particularly in dynamic mode due to the presence of the resin rich pockets. Alternative solutions emerge, which may help reach a cost-effective compromise.