The post-impact fatigue response of a graphite/epoxy composite laminate

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:501719

Skordahl, R ^[1]; Mahinfalah, M ^[2]

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1. United Defense LP, Minneapolis, MN (United States)
2. North Dakota State Univ., Fargo, ND (United States)

An investigation was undertaken to determine the effects of impact damage on the fatigue strength of a graphite/epoxy composite laminate. Two different types of projectiles were used to impact sixteen-ply graphite/epoxy coupons. These coupons were subjected to either 7.1 J or 27.4 J impacts by simulated hailstones or hard particle projectiles. Molded iceballs of 25.4 mm or 38.1 mm in diameter were used to simulate hailstones, while 12.7 mm diameter aluminum spheres were used for hard particle impacts. Inspection revealed that neither iceball impact event caused any internal damage, while each aluminum sphere impact caused delaminations within each coupon. After being impacted and inspected, each coupon was subjected to constant amplitude tension-tension fatigue and the S-N behavior of this material after each impact event was modeled. Neither type of impact at the 7.1 J energy level affected this laminate. The hard particle impact at 27.4 J adversely affected the fatigue performance of this laminate while the simulated hailstone impact at the same energy level did not.

• OSTI ID: 501719
• Report Number(s): CONF-961239--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
99 GENERAL AND MISCELLANEOUS
COMPOSITE MATERIALS
EPOXIDES
FATIGUE
GRAPHITE
IMPACT TESTS
PERFORMANCE
REINFORCED MATERIALS