A fracture mechanics evaluation on the fatigue crack propagation at spot welded aluminum joint in passenger car body

J. Ocean Eng. Technol. 1997;11(3):20-28.

스폿용접된 자동차 차체용 알루미늄 박판의 피로균열진전의 파괴역학적 평가

박인덕,남기우,강석봉

부경대학교 대학원,부경대학교 재료공학과,한국기계연구원 재료기술연구부

Keywords: Fatigue, Fracture Mechanics, Spot Weld Joint, Fatigue Limit, Fatigue Crack Propagation, Stress Intensity Factors

핵심용어: 피로, 파괴역학, 스폿용접부, 피로한도, 피로균열진전, 응력확대계수

Abstract

The fatigue crack propagation properties and fatigue life of two kinds of Al body panel for automobile were examined experimentally by using the plate specimen and the single spot welding specimen. The fatigue limit of spot welding specimens was lower than that of a plate specimen. The fatigue limit was similar in two kinds of spot welding specimen. The shape and size of crack propagation were observed and measured on beach mark of fracture surface. The crack propagation of surface crack specimen showed almost same tendency to that of a thick plate as almost semi-elliptical. In spot welding specimen, the fatigue crack occurred in inside surface of nugget area was almost semi-elliptical. The crack growth rate can be explained using equation of stress intensity factors.