Effect of Drilling-Induced Delamination on Buckling Behavior of Open Hole Composite Laminate Specimens Under Compressive Loading

The effect of drilling-induced delamination defects on the buckling behavior of open-hole composite laminates specimens is experimentally studied. PTFE (polytetrafluoroethylene) films are inserted into the ply interface around the hole as artificial delaminations to quantify the drilling-induced one. Artificial delaminations in two shapes (circular and square) and three sizes (10, 15, and 20 mm) are designed. The effect of various drilling-induced delaminations on local buckling, local buckling-induced delamination and general buckling are examined and evaluated using an ultrasonic C-Scan UPK-T48-HS and the digital image measurement system (VIC-3D). Quantitative information, including critical buckling loads, are provided to assess the effect of drilling-induced delamination on the compressive behavior of composite laminates with open holes. The results are expected to give an insight into the assessment of the damage tolerance of the interstage design and establishment of appropriate thresholds for a safety inspection.