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EFFECT OF A SINGLE PEAK OVERLOAD ON PHYSICALLY SHORT FATIGUE CRACK RETARDATION IN AN AXLE‐STEEL

1996; Wiley; Volume: 19; Issue: 2-3 Linguagem: Inglês

10.1111/j.1460-2695.1996.tb00959.x

8756-758X

Zheng Chang-qing, J. Yucheng, Yang Guang-li,

Non-Destructive Testing Techniques

Abstract— Experiments on the propagation behaviour of physically short fatigue cracks were conducted on an axle‐steel, using a direct current potential technique. Various overload ratios (OLR = 1.5, 1.7, 1.9 and 2.1) and different overload positions were employed. The experimental results show that physically short cracks are more sensitive to the overload retardation effect than long cracks. The overloads produce a beneficial effect when they are introduced early. Later overloads, although giving an increase in life, produce a smaller effect. The delay cycles N D due to the application of a single overload increase with increasing overload ratios. The experimental data, when plotted on a log‐log graph of N D / N CAL (where N CAL is the number of cycles under constant amplitude loading) versus overload ratio OLR, gives a straight line relationship, namely N D / N CAL = 2.81 × 10 −3 (OLR) 10,12 .