Effect of drilling induced damage on notched tensile and pin bearing strengths of woven GFR-epoxy composites

Analytical and experimental studies were made to evaluate the notched tensile and pin bearing strengths of the woven glass fiber reinforced (GFR)-epoxy composite laminates. The symmetric glass/epoxy woven mat cross-ply laminates containing 16 woven mats were prepared using hand lay-up technique with 45% of volume fraction. The laminates were cut into specimens as per ASTM standards. The experiments were done at three different feed rates, spindle speeds and hole diameters to examine the influence of drilling parameters on the notched tensile strength and bearing strengths of the laminates. The design of experiments and analysis of variance (ANOVA) techniques of Taguchi, were utilized to study the statistical influence of the drilling parameters on the extension of delamination. The fracture data of center-hole tensile specimens were correlated using a modification in one of the stress fracture criteria viz., the point stress criterion (PSC). The bearing strength was correlated with notched and un-notched tensile strengths of the woven fabric composite laminates.