Rate dependence of mode I fracture behaviour in carbon-fibre/epoxy composite laminates

doi:10.1016/S0266-3538(97)00176-0

Composites Science and Technology

Volume 58, Issues 3–4, March–April 1998, Pages 591-602

https://doi.org/10.1016/S0266-3538(97)00176-0 Get rights and content

Abstract

The rate dependence of mode I interlaminar fracture behaviour in unidirectional carbon-fibre/epoxy composite laminates has been investigated over a wide range of loading rates from quasi-static (displacement rate, δ = 0.01–500 mm min⁻¹) to impact (δ = 5–20 mm see⁻¹) at room temperature. Impact fracture tests were performed by the WIF (wedge-insert-fracture) method with a SHPB (split Hopkinson pressure bar) system for accurate measurement of impact fracture toughness, while quasi-static fracture tests were performed by the DCB (double-cantilever-beam) method with a screw-driven testing machine. In the present composite laminates, the fracture toughness decreased stepwise with increasing loading rate showing a distinct rate-sensitive transition region and two rate-insensitive regions above and below. As a consequence of this stepwise characteristic, the crack growth behaviour varied with loading rate: in and below this transition region, the crack grew unstably accompanied by high-speed propagation and arrest; but above the transition region, the crack grew stably and continuously. This trend was well explained by a simple model incorporating the rate dependence of fracture toughness and the contribution of kinetic energy in the specimen during unstable crack propagation.

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Rate dependence of mode I fracture behaviour in carbon-fibre/epoxy composite laminates

Abstract

Composites

Composites

Polymer

Compos. Sci. Technol.

Compos. Sci. Technol.

Characterizing delamination growth in graphite-epoxy

A double cantilever beam test for characterizing mode I delamination of composite materials

J. Reinforced Plastics and Composites

The analysis of interlaminar fracture in uniaxial fibre-polymer composites