Title: Evaluation of Deep Learning Architectures for Defect Detection in Fused Filament Fabrication

Authors: Israt Sharmin Dola, Rakin Ahmed, Muhammed Jawaad Zulqernine, Tanvir Ahmed Shanto, Robert M Taylor

DOI:

Abstract: Ballistic armor is designed to withstand the impact of firearms and shrapnel. Current armor uses face layers of flexible materials, such as aramid fibers, combined with dense backing plates made of ceramics or metals to both stop bullets and minimize blunt-force trauma. These backing plates provide strong protection for the wearer but are often heavy, limiting mobility. To address these limitations, this study investigates composite sandwich structures as a lightweight alternative for ballistic protection applications. This work evaluates the ballistic performance of sandwich structures composed of woven Kevlar face sheets, polyurethane interlayers, and composite backing panels with varying fiber types, orientations, and thicknesses. Nanomaterial additives, such as graphene nanoplatelets, carbon nanotubes, and nanoclay, were explored as modifiers for the polyurethane interlayer to enhance energy absorption. Composite panels and polyurethane layers were fabricated and mechanically characterized prior to assembly into sandwich structures. Both individual composite panels and assembled sandwich structures were experimentally evaluated under 9mm hollow-point and fullmetal-jacket ballistic impact. Sandwich structures incorporating nanomaterial-modified polyurethane were also evaluated during ballistic testing; however, processing-related effects reduced mechanical integrity and ballistic effectiveness relative to unmodified polyurethane layers. Therefore, the most effective sandwich structures utilized unmodified polyurethane interlayers, thick, sewn Kevlar face sheets, and high-quality composite backing panels. The optimized configurations achieved penetration depths as low as 8% of the total sample thickness. These results highlight the importance of manufacturing quality and layer architecture in the design of composite sandwich structures for ballistic armor and provide guidance for future studies seeking to incorporate nanomaterials in ballistic applications.

References: Ballistic armor is designed to withstand the impact of firearms and shrapnel. Current armor uses face layers of flexible materials, such as aramid fibers, combined with dense backing plates made of ceramics or metals to both stop bullets and minimize blunt-force trauma. These backing plates provide strong protection for the wearer but are often heavy, limiting mobility. To address these limitations, this study investigates composite sandwich structures as a lightweight alternative for ballistic protection applications. This work evaluates the ballistic performance of sandwich structures composed of woven Kevlar face sheets, polyurethane interlayers, and composite backing panels with varying fiber types, orientations, and thicknesses. Nanomaterial additives, such as graphene nanoplatelets, carbon nanotubes, and nanoclay, were explored as modifiers for the polyurethane interlayer to enhance energy absorption. Composite panels and polyurethane layers were fabricated and mechanically characterized prior to assembly into sandwich structures. Both individual composite panels and assembled sandwich structures were experimentally evaluated under 9mm hollow-point and fullmetal-jacket ballistic impact. Sandwich structures incorporating nanomaterial-modified polyurethane were also evaluated during ballistic testing; however, processing-related effects reduced mechanical integrity and ballistic effectiveness relative to unmodified polyurethane layers. Therefore, the most effective sandwich structures utilized unmodified polyurethane interlayers, thick, sewn Kevlar face sheets, and high-quality composite backing panels. The optimized configurations achieved penetration depths as low as 8% of the total sample thickness. These results highlight the importance of manufacturing quality and layer architecture in the design of composite sandwich structures for ballistic armor and provide guidance for future studies seeking to incorporate nanomaterials in ballistic applications.

Conference: SAMPE 2026

Publication Date: 2026/04/27

SKU: 91

Pages: 14

Price: $28.00