疲労き裂伝ぱ・停留シミュレーションによる鋼の組織設計

概要

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The fatigue limits of single-, dual-and tri-phase steels were estimated using the crack-growth and arrest simulation, which was based on a model for continuous distribution of dislocations ahead of a small fatigue crack tip. The effects of microstructural parameters such as grain size, hardness and volume fraction of the three phases on the fatigue limit were systematically analyzed using this simulation. The simplified estimation equation for fatigue limit was derived from the simulation results as follows : δ_w=HV_1・(k_1+k_2/√<D_1>)+Σ_<j=2,3>(HV_j-HV_1)・V_j・(k_<3j>+k_<4j>/√<D_j>), where HV_j is the hardness, D_j is the grain size, and V_j is the volume fraction of the j-th phase. Microstructural design for high fatigue strength steels is discussed with reference to this equation. Also, a more accurate simulation method is outlined including the effects of cyclic hardening and softening behavior of materials.
1997-10-25