Influence of 2D and 3D Arrangements of Aramid Fibers on the Dart Drop Test of Epoxy Composites

Abstract

The use of continuous fibers reinforced polymeric composites has increased substantially in the last year's due to their high specific mechanical strength compared to other materials. Despite this property, this class of material is susceptible to low, medium, or high energy impacts, which can cause severe damage to composite laminates. One of the most serious damages is delamination, which can lead to partial or total rupture of the structure. In order to minimize this problem, several studies have been carried out in this area. In this context, this work aims to evaluate the influence of aramid reinforcement with bi-directional (2D) and tri-directional (3D) arrangements impregnated with two epoxy resins of different stiffness on the impact strength of composites submitted to the 340 J dart drop test. The impact results showed that the 2D composites had lower impact strength than the 3D ones, with the presence of perforations (when impregnated with the more rigid resin) and delaminations. Delaminations occurred regardless of the epoxy resin used in the impregnation. On the other hand, the 3D composites impregnated with the less rigid epoxy matrix absorbed more energy (3DF: 97.9%) with less deformation and no delamination compared to the 2D laminate (2DF: 96.1%) produced.

Designing a Laboratory Stand for Testing Impact Resistance of Plastic Films by Free-Falling Dart Drop According Astm D1709

“…The wide application of a variety of polymers in modern engineering requires study of their main mechanical characteristics -hardness, strength and plastic characteristics, impact resistance [4]. Impact resistance of polymers and composites are mainly done by dart drop methods [5], [6]. [7].…”