Journal of Stress Analysis

Journal of Stress Analysis

An Experimental Study of Static and Dynamic Behaviors of Kevlar in Fiber, Fabric and Kevlar/Epoxy Composites

Document Type : Original Research Paper

Authors
G.H. Majzoobi
F. Mohammad Zaheri
Mechanical Engineering Department, Bu-Ali Sina University, Hamedan, Iran
10.22084/jrstan.2025.27509.1235
Abstract
Kevlar is a trademarked brand of aramid fibers. It is known for its remarkable properties, including high tensile strength, light weight, and resistance to heat, and it is commonly used in various applications. In this study, the strength and fracture mechanisms of Kevlar in different forms, including Kevlar fibers, Kevlar fabric impregnated with and without grease as a lubricant, unwoven fibers, and Kevlar/epoxy, were experimentally investigated. The tests were conducted under quasi-static and high-rate loading conditions. The experimental results showed that the addition of resin epoxy or grease to Kevlar increased its brittleness. The failure of the Kevlar/epoxy composite was characterized as completely tensile, indicating brittle failure. Additionally, the failure of the Kevlar/epoxy composite was caused by crack formation in the matrix, followed by the separation of the fibers from the matrix. In contrast to the Kevlar/epoxy composite, the failure of the Kevlar fabric occurred in the shear mode, indicating ductile failure. A punch test was also conducted, and the results showed a ductile fracture mechanism for Kevlar fabric and brittle failure for the Kevlar/epoxy composite. Finally, the dynamic behavior of Kevlar fiber at high strain rates was evaluated using a split Hopkinson bar apparatus. The results indicated that the strength of the Kevlar fibers increased with increasing strain rate.
Keywords
Kevlar fiber
Kevlar fabric
Kevlar/epoxy composite
Dynamic behavior
Fracture mechanism
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Journal of Stress Analysis
Volume 8, Issue 2
2024
Pages 65-72