An evaluation of Fatigue Crack Propagation Behaviors on Cyclic Overload Test

반복과대하중에 의한 피로파괴거동의 고찰

  • 김용수 (서울산업대학) ;
  • 신근하 (아주대 생산자동공학과) ;
  • 강동명 (서울산업대학 산업안전공학과) ;
  • 김병석 (한국산업인력관리공단)
  • Published : 1992.06.01

Abstract

The retardation effect of fatigue crack propagation after cyclic overloading seems to be affected by strain hardening exponent. Namely, for the material with high values of n, the delay effect is found to be severe. We proposed a modified crack retardation equation which may apply the retardation of fatigue crack growth after a cyclic overloading, as (da/dN)'$_{cyc}$=($\mu$n+λ)B $\Delta$ $K^{q}$ /[(1- $R_{eff}$) $K_{cf}$$\Delta$K]. where, $R_{eff}$ is effective stress ratio [=( $K_{min}$-K, os)/( $K_{max}$$K_{res}$)] The constants $\mu$=-0.5 and λ=0.6, and the values are found to be identical for materials such as aluminum (A 1060), steel (SS 34), brass ( $B_{s}$ SIB) and stainless steel (SUS 304) used in this investigation. (SUS 304) used in this investigation.ation.n.n.

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