高温多軸疲労き裂発生・成長に対する制御因子とき裂成長メカニズム

抄録

Under multiaxial loading conditions, high temperature fatigue crack growth tests for SUS 304 stainless steel were conducted. In this study, effects of applied stress level and specimen geometry on multiaxial fatigue crack growth were investigated experimentally. DC electrical potential drop method was applied to the thin-walled cylindrical specimen subjected cyclic tension and torsion. Controlling factor of multiaxial crack initiation and fatigue crack growth are examined. Fatigue crack growth characteristics changes with the combined stress condition, Δτ/Δσ. Under the condition of large value of Δτ/Δσ,crack growth rate is decelerated during the early stage and the middle stage of crack growth. Based on the result of fractography, crack growth mechanisms under multiaxial loading condition are also discussed.