4.5.1 Introduction 过程设备设计 High cycle fatigue: N>10 Low cycle fatigue: N=102-105 102 10310410510510710 Cycle number M Fig4-62 Stress cyclic curve Fig4-6. High cycle fatigue curve
6 4.5.1 Introduction High cycle fatigue: N>105; Low cycle fatigue : N=102~105 8 Fig.4-63 High cycle fatigue curve σa σ t σa σmσm ax σm i n S t r e s s a mp l i t u d e σa 103 104 105 106 107 10 σ−1 103 102 Cycle number N Fig.4-62 Stress cyclic curve
4.5.2 Low cycle fatigue curve 过程设备设计 4.5.2 Low cycle fatigue curve Calculated curve for low cycle fatigue S=-EE (4-92) NE=O (4-93) P 100 where C ef=1100-v where e is the true strain at fracture and y is the percentage reduction in area
7 4.5.2 Low cycle fatigue curve 4.5.2 Low cycle fatigue curve Calculated curve for low cycle fatigue S E t ε 21 = 4-92 Nε p = C 4-93 where C f ε21 = ψ ε − = 100100 ln f where f ε is the true strain at fracture and ψ is the percentage reduction in area.