Fracture and Fatigue Crack Growth Behavior of Surface Flaws and Flaws Originating at Fastener Holes. Volume 1. Results and Discussion
Final technical rept. 30 Jun 1972-30 Sep 1973
BOEING AEROSPACE CO SEATTLE WA
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The combined experimental and analytical study was undertaken to investigate the fatigue crack growth behavior of surface flaws and part-thru and thru cracks originating at fastener holes. Three alloys 2219-T851 aluminum, 9Ni-4Co-0.2C steel, and 6Al-4V ELI beta annealed titanium were tested under three different loading profiles constant cyclic load, periodic overload, spectrum load. Surface flaw test variables included loading conditions uniform tension, pure bending, combined bending and tension, stress ratio 0. 1, 0.3, 0.5, initial flaw shape 0.15 a2c 0.45, and initial flaw depth 0.2 at 0.8. Fastener hole flaw variables included hole condition conventional reamed and cold worked, fastener type close tolerance and Taper- lok, and initial crack shape uniform thru the thickness and quarter circular part-thru. All tests were conducted in air having a relative humidity of about 10 percent.
- Metallurgy and Metallography
- Couplers, Fasteners and Joints