A MICROMECHANICAL APPROACH TO INVESTIGATE THE INFLUENCE OF VOIDS ON THE STRUCTURAL BEHAVIOUR OF FRP UNDER COMPRESSION LOADING

The subject of this presentation is to develop a micromechanical approach to investigate the influence of voids on the structural behaviour of FRP under compression load. Therefore, the fibrematrix-void constellation was analysed and a reduced model composite was conducted. The idea was to imitate a real void in a fibre-reinforced polymer where they appear between fibres and in resin rich areas. Elementary experimental and numerical studies were conducted due to the reduced model (two or more fibres and a unique void between). For the experiments a test jig was designed which fits in a light microscope with integrated photoelasticity and potential digital image correlation. While testing at different load steps the stress and strain material behaviour were analysed. Furthermore, the failure mechanisms (fibre-matrix debonding, fibre buckling and kinking) of the composite could be observed in situ. Numerical studies were compared with the test results. They included a detailed and step by step analysis of the failure mechanisms, especially of the premature fibre buckling.

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