Detection of resin-rich areas for statistical analysis of fiber-reinforced polymer composites

Abstract

Resin-rich areas (a.k.a. resin-rich zones or resin pockets) are a common phenomenon in fiber-reinforced polymer (FRP) composites that significantly impact composite material properties and failure initiation. Although resin-rich areas can be intuitively observed from composite cross-sectional images, it is challenging to automate identifying them due to the absence of an explicit definition of their boundaries. In this paper, a novel algorithm is proposed to automatically identify resin-rich areas from composite cross-sectional images. We apply the concept of alpha-hulls to formalize a mathematical definition of the boundaries of resin-rich areas, and design an efficient process to compute the defined boundaries in seconds. This approach enables us to provide statistical analyses to quantitatively summarize the identified resin-rich areas, such as the number of separated areas and the histogram of their sizes. The rigorous mathematical definition of resin-rich areas and ability to collect thorough statistics will facilitate better understanding and quantification of the relationship between resin-rich areas and material properties.