Photoelastic study of stresses in the vicinity of a unique void in a fibre-reinforced model composite under compression

• Published in: Composites science and technology Vol. 84; pp. 72 - 77
• Main Authors: Liebig, W.V., Leopold, C., Schulte, K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 29.07.2013; Elsevier
• Subjects: Applied sciences; B. Fibre/matrix bond; B. Porosity/voids; C. Stress concentrations; Composites; Compressing; Devices; Exact sciences and technology; Fiber composites; Fiber reinforced plastics; Fibre; Forms of application and semi-finished materials; Photoelasticity; Polymer industry, paints, wood; Stress concentration; Stresses; Technology of polymers; Voids; B. Porosity/voids; Photoelasticity; B. Fibre/matrix bond; C. Stress concentrations; Fiber reinforced material; Epoxy resin; Mechanical properties; Compressive strength; Experimental study; Composite material; Stress distribution; Measurement method; Fracture mode
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2013.04.011

The subject of this work is the investigation of the stress field around a unique void in a fibre-reinforced model composite under compression. Voids were introduced into the epoxy material by injection. The idea was to imitate a real void in fibre reinforced plastics (FRP) where voids appear between fibres and in resin rich areas. To investigate the mechanical response of the composite material under compression, a test jig was designed, which fits into a light microscope with an integrated photoelasticity device. That way in situ measurements were conducted. It could be demonstrated, that voids have a significant influence on the stress distribution in the matrix which leads to stress concentrations particularly around the end caps and the longitudinal side of the voids. Furthermore, different failure mechanisms like fibre matrix debonding and fibre buckling could be observed.