Experimental and Numerical Investigation of Mixed-Mode Interlaminar Fracture of Carbon-Polyester Laminated Woven Composi

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Experimental and Numerical Investigation of Mixed-Mode Interlaminar Fracture of Carbon-Polyester Laminated Woven Composite by Using Arcan Set-up Mohammad Hossein Heydari & Naghdali Choupani & Moharram Shameli

Received: 16 March 2011 / Accepted: 1 August 2011 / Published online: 11 August 2011 # Springer Science+Business Media B.V. 2011

Abstract Composite materials are widely used in marine, aerospace and automobile industries. These materials are often subjected to defects and damages from both in-service and manufacturing process. Delamination is the most important of these defects. This paper reports investigation of mixed-mode fracture toughness in carbon–polyester composite by using numerical and experimental methods. All tests were performed by Arcan set-up. By changing the loading angle, α, from 0° to 90° at 15° intervals, mode-I, mixed-mode and modeII fracture data were obtained. Correction factors for various conditions were obtained by using ABAQUS software. Effects of the crack length and the loading angle on fracture were also studied. The interaction j-integral method was used to separate the mixed–mode stress intensity factors at the crack tip under different loading conditions. As the result, it can be seen that the shearing mode interlaminar fracture toughness is larger than the opening mode interlaminar fracture toughness. This means that interlaminar cracked specimen is tougher in shear loading condition and weaker in tensile loading condition. Keywords Mixed-mode fracture . Fracture toughness . Laminated woven composite . Crack . Arcan set-up

1 Introduction Carbon fiber composites, particularly those with polymeric matrices, have become the dominant advanced composite materials for aerospace, automobile, sporting goods, and other applications due to their high strength, high modulus, low density and reasonable cost. The mechanical properties of the laminated composite depend very much on the properties of the each lamina. The behavior of each lamina is governed by its constituents, i.e. the properties of the fibers, the surrounding matrix, the interface and the relative amount of fiber and matrix in the lamina. Delamination represents the weakest failure mode in laminated composites, and is considered to be the most prevalent life-limiting crack growth mode in most composite structures. In general, a M. H. Heydari : N. Choupani (*) : M. Shameli Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran e-mail: [email protected]

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delamination will be subjected to crack driving forces resulting from either or combination of mode-I (opening or peeling), mode-II (sliding or in-plane shear) and mode-III (tearing or antiplane shear). Because delamination is constrained to grow between individual plies, both interlaminar tension and shear stresses are commonly present at the delamination front [1–4]. A number of test methods have been proposed by many researchers to determine fracture toughness of metals, composites and adhesively bonded