Paper number 242

CHARACTERIZATION OF DELAMINATION TOUGHNESS OF ANGLE-PLY GLASS/EPOXY CYLINDERS

F. Ozdil¹, L. A. Carlsson¹ and P. Davies²

1 Department of Mechanical Engineering, Florida Atlantic University
Boca Raton, FL 33431, USA
2 Marine Materials Laboratory, IFREMER, 29280 Plouzané, France

Summary

Delamination growth in filament-wound glass/epoxy composite cylinders is examined. Analysis and experiments on DCB, ENF and MMB specimens machined from the cylinder wall are presented. The beam axis was parallel to the cylinder axis making the cross-section curved, but the beam axis straight. Experiments on beam specimens machined from glass/epoxy cylinders were conducted on 6 and 12 lay-ups, where is the winding angle with respect to the cylinder (and beam) axis (= 30°, 55° and 85°). Fracture toughness data were reduced from experimental data using specially developed beam analysis and experimental compliance calibration methods. It was found that the initiation value of fracture toughness corresponding to crack propagation from the film insert increased with increased mode II fraction, GII / G, and increased ply angle,. External pressure tests performed on cylinders with artificial defects and impact damage revealed that the cylinder implosion behavior was insensitive to the presence of single delaminations but impact damage caused reductions in failure pressure.

Keywords

cylinders, interlaminar fracture, mixed mode, delamination.