Fatigue Crack Growth Behavior due to the Localized Compressive Deformation on Structural Steel

ABSTRACT The localized compressive deformation (LCD) process was used to analyze the fatigue crack growth behavior of a high‐strength low‐alloy structural steel. Eccentrically loaded single‐edge crack tension specimens (ESE(T)) in accordance with standard ASTM E647 were precracked at a crack length of about 4 mm from the machined notch by applying a constant amplitude cyclic loading. Subsequently, the LCD process was performed by using semi‐spherical indenters to compress both sides of the specimen at the crack tip with different forces (5.0, 7.5, 10 kN). The compressive load and the number of delayed loading cycles are discussed in terms of the crack length and crack tip opening displacement (CTOD). The crack arrest due to the LCD effect increases as a function of increasing the compressive force. The crack was arrested for more than 10 6 cycles when a compressive force of 10 kN was applied. This phenomenon was analyzed experimentally. Biaxial‐stacked rosettes (C4A‐06‐G1350A‐120‐39P) were used to measure the strain during the crack propagation as well as the strain modification at the crack tip due to the LCD process. Stress–strain relations were used to determine the stress state induced by the LCD.