Evaluation of Bolt Bearing Behavior of Highly Loaded Composite Joints at Elevated Temperature

Abstract

The high load intensities and elevated temperature in the wing and fuselage of a supersonic transport aircraft will result in bolted joints stack-up thickness much greater than the current subsonic transport aircraft. Bolt bearing– bypass tests were conducted to develop a database and a bearing–bypass stress interaction for the design community. All test coupons are IM7/PETI-5 quasi-isotropic laminates (64 plies) with a bolt-hole for a 0.95 cm diameter fastener. Static tests were conducted at room temperature as well as at 177 C. Thermo-mechanical fatigue tests were conducted using a typical supersonic transport flight spectrum loading. Short-term creep tests,of 250 h,indicated that IM7/PETI-5 quasi-isotropic (64 plies) laminates has improved properties over IM7/K3B. Long-term creep tests, of 10,000 h, demonstrate that IM7/PETI-5 is highly creep resistant for long periods. Test results also show that these composites experience very little hole elongation before failing in a bearing mode.