Issue34

M. Ševčík et al, Frattura ed Integrità Strutturale, 34 (2015) 216-225; DOI: 10.3221/IGF-ESIS.34.23 216 Focussed on Crack Paths Analytical model of asymmetrical Mixed-Mode Bending test of adhesively bonded GFRP joint M. Ševčík, P. Hutař Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v. v. i., Žižkova 22, 616 62 Brno, Czech Republic sevcik@ipm.cz; hutar@ipm.cz A. P. Vassilopoulos Composite Construction Laboratory CCLab, Ecole Polytechnique Fédérale de Lausanne EPFL, Station 16, CH-1015 Lausanne, Switzerland anastasios.vasilopoulos@epfl.ch M. Shahverdi Structural Engineering Research Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland moslem.shahverdi@empa.ch A BSTRACT . This paper presents new analytical model of asymmetric mixed-mode bending (MMB) specimen of adhesively bonded pultruded GFRP joints. An easily applicable relationship for the calculation of the strain energy release rate of the asymmetric MMB specimens is proposed based on the beam theory. The model is capable to analyze stacking sequence as well as various crack propagation paths. In the paper the effect of the various fiber bridging length and different crack propagation paths is analyzed analytically and supported by experimental results. The methodology and results presented in this paper could be utilized for the design of both joint geometry and lay-up of the laminates constituting the joint or for the prediction of the fracture behavior of such structures. K EYWORDS . GFRP materials; Mixed-Mode bending; Fiber bridging; Analytical model. I NTRODUCTION iber reinforced polymers are modern kind of materials that benefit from their high stiffness vs. weight ratio. Composite materials are being widely used for aeronautical and space applications for decades. Despite theirs higher initial price these materials can be used also in the civil engineering applications. Material of fibers strongly influences the overall strength of the fiber reinforced polymer materials. Glass or aramid fibers are usually used for the civil applications [1] whereas carbon fibers are used mostly for aerospace and automotive applications [2]. Connection of composite laminates is typically performed by adhesive joint. The strength of the adhesive should be higher than interlaminar strength of the laminate. Therefore, the failure should occur between layers of the laminate rather than in the adhesive layer. Unlike the mechanical engineering applications where the adhesive layer thickness is far below F

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