Paper number 978

DAMAGE PROGRESSION AND RESIDUAL TENSION STRENGTH STUDY OF FATIGUED OPEN-HOLE TITANIUM-GRAPHITE HYBRID COMPOSITE LAMINATES

W. Steven Johnson¹ and William B. Bright¹

1Department of Materials Science and Engineering, Georgia Institute of Technology,
778 Atlantic Drive, Atlanta, Georgia 30332-0245, USA

Summary

Titanium graphite hybrid composite laminates are under consideration as a potential material for future supersonic aircraft. In order to be used on such vehicles, issues of damage tolerance and durability must be investigated. This study examines one lay-up with respect to damage progression and residual tension strength. The Open-Hole Tension (OHT) specimens are fatigued for one million cycles. The damage created in the laminates is monitored by the use of x-ray radiographs taken at various intervals. Finally, the residual tension strength is measured in a tensile test. The lay-up in this study demonstrates an average increase in residual strength of approximately 14% after significant damage accumulates in the titanium plies. Results from this study show that extensive cracks in the titanium plies do not reduce the structural integrity of the laminates when loaded in tension.

Keywords

hybrid composite laminate, fatigue, titanium, damage tolerance, residual strength.