Fatigue Behavior of Cracked Al 6061-T6 Alloy Structures Repaired with Composite Patch

  • Yoon, Young-Ki (School of Mechanical Engineering, Chonnam National University) ;
  • Park, Jong-Joon (School of Mechanical Engineering, Chonnam National University) ;
  • Kim, Guk-Gi (School of Mechanical Engineering, Chonnam National University) ;
  • Yoon, Hi-Seak (School of Mechanical Engineering, Chonnam National University)
  • Published : 2001.09.01

Abstract

Due to the development of high-strength fibers and adhesives, it is now possible to repair cracked metallic plates by bonding reinforced patches to the plate over the crack. In this study, pre-cracked aluminum 6061-T6 alloy plates repaired with bonded carbon/epoxy composite patch are applied to investigate the effect of various patch shapes on the tensile strength and the fatigue behavior of the structure. A non-patch-boned cased and 2 type-50$\times$50, 40$\times$20 mm-composite patch-bonded cases were tested to obtain fracture loads and fatigue crack growth rate. The results showed that the patch-bonded repair improves the static strength by 17% and the fatigue life by 200% compared to non-repaired case. It means that patch-boned repair is more effective in the fatigue life. It was also revealed that the patching method along crack growth direction is more efficient in cost and weight reduction. By observing the fractography, patch-bonded repair specimens demonstrated zigzag fracture patterns compared with the non-patched specimens, which shows a typical ductile fracture.

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