Investigating Planar Delamination Behavior in Carbon Fiber Reinforced Polymer Panels: An evaluation of delamination criteria

The relation between planar delamination growth, induced by transverse quasi-static load case, and the coupon delamination validation tests was investigated by evaluating the delamination criteria. The delamination criterion that allowed to describe planar delamination growth was the strain energy density criterion. An analytical study was performed to relate the elliptical delamination growth in planar delamination growth with the material properties through the strain energy density criterion. Following to this study, an experimental setup was designed to measure the delamination boundary during the transverse load induction of a planar specimen. With this new experimental setup both quasi-static and fatigue tests were performed with quasi-isotropic planar specimen which have artificial delaminations. For the fatigue tests that were performed on this experimental setup, a methodology was proposed on determining the strain energy release rate. The outcomes of the quasi static tests were then compared with a numerical model based on mode-partitioning virtual crack closure technique. All the different studies demonstrated that the physical strain energy release rate was the metric to asses the delamination behavior in a planar fatigue experiment. The delamination criterion that was applicable for planar delamination problems is the strain energy density criterion which measured and predicted the delamination size.Aerospace Engineerin