Effect of Anisotropy on Fatigue Crack Propagation Rate and Arrest Behavior with 2024-T3 Alumunum Alloy

J. Ocean Eng. Technol. 1993;7(1):124-132.

2024-T3 A1 합금의 이방성이 피로균열진전속도와 정류거동에 미치는 영향

오세욱,김태형,오정종

동아대학교 공과대학기계공학과,동아대학교 공과대학기계공학과,동아대학교 공과대학기계공학과

Keywords: Single tension peak onerload, Crack arrest, Anisotropy, Fatigue crack opening closing behavior, Delayed retardation, Threhold overload shut off ratio, Rso

핵심용어: 단일인장과대하중, 전류구렬 개.폐구 거동, 연, 림계정류과대망중비

Abstract

In order to examine the effect of anisotropy and stress ratio on fatigue crack propagation rate and opening-closing behavior and also arrest behavior by single tension peak overload, the fatigue tests of constant amplitude atress and single tension peak overload adding to cycle of constant amplitude were carried out in stress ratio of -0.4, -0.2, and 0.4 with materials of T-L and L-T directions in 2024-T3 aluminum alloy plate. Crack opening-closing begavior were measured by the compliance method using COD gage and strain gage. In case of the crack opening-closing behavior was measured by strain gage, the effect of stress ratio is unchangeable. But in the case of COD gage, that is remarkably decreased. Fictitious effective stress intensity factor(U sub(f)) and effective stress intensity factor ratio(U) in L-T direction was higher than those in T-L direction and also threshold arrest overload ratio incrased as stress ratio decreased and that of T-L direction was higher than that in L-T direction.