Abstract
Transverse cracking behaviour in a quasi-isotropic glass/epoxy (GFRP) laminate loaded in flexure is studied experimentally and theoretically. A theory developed for cross-ply laminates is applied to a [0°/90°/−45°/45°] S quasi-isotropic laminate. An equivalent laminate is introduced to derive the Young's modulus of a cracked transverse ply on the basis of a shear lag analysis. The model predicts the flexural stiffness, the neutral axis position and the residual curvature as a function of the transverse crack density and the in-situ ply stress at first ply failure. Experimental results are obtained with the use of the applied moment – strain data in four-point flexural tests and compared with predictions. Time-dependent behaviour of the residual curvature is also investigated.
The theoretical predictions are in reasonably good agreement with the experimental results. It is found that the decrease in the residual curvature after unloading is mainly ascribed to viscoelasticity of the material.
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Ogi, K., Smith, P.A. Characterisation of Transverse Cracking in a Quasi-Isotropic GFRP Laminate under Flexural Loading. Applied Composite Materials 9, 63–79 (2002). https://doi.org/10.1023/A:1013861917143
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DOI: https://doi.org/10.1023/A:1013861917143