## Abstract

In this paper, the result from rotating bending fatigue tests of notched specimens are carried out on aluminum cast alloys and high strength steels with H_{B} ≃ 600 are reported. The threshold stress intensity factor range under a stress controlled condition, ΔK_{w}, is introduced for the purpose of predicting the fatigue limit of a metal with an arbitrary crack. The ΔK_{w} value of a long crack, ΔK_{wU} _{L}, is obtained from the fatigue crack propagation limit σ_{W2} of specimens with a sharp and deep notch; ΔK_{w} increases with crack length, and ΔK_{wU} _{L} is an upper limit of ΔK_{w}, Since there are few σ_{w2} data of steels with H_{B} ≥ 400, the σ_{w2} values are evaluated by the fatigue crack initiation limit predicted using Linear Notch Mechanics and the relation between σ_{w1} and σ_{w2} at the branch point. Using ΔK_{wU} _{L} values of many metals with a long crack, the ΔK_{WU} _{L} values are approximated with a simple formula. Moreover the lower limit value of ΔK_{wU} _{L} versus the crack length, ΔK_{wLL}, is proposed. Then using the AK_{w} and ΔK_{wUL} formulae and the ΔK_{wLL} value, the smallness of a fatigue crack is clarified.

Original language | English |
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Pages (from-to) | 21-38 |

Number of pages | 18 |

Journal | International Journal of Fracture |

Volume | 129 |

Issue number | 1 |

DOIs | |

Publication status | Published - Sept 2004 |

## All Science Journal Classification (ASJC) codes

- Computational Mechanics
- Modelling and Simulation
- Mechanics of Materials