Effects of Strain Rate on Low Cycle Fatigue Behaviors of High-Strength Structural Steel

• Published in: Journal of iron and steel research, international international, 2013-07, Vol.20 (7), p.50-56
• Main Authors: Luo, Yun-rong, Huang, Chong-xiang, Tian, Ren-hui, Wang, Qing-yuan
• Format: Article
• Language: English
• Subjects: Applied and Technical Physics; Engineering; Fatigue failure; Iron and steel industry; Low cycle fatigue; Machines; Manufacturing; Materials Engineering; Materials Science; Metallic Materials; Physical Chemistry; Plastic deformation; Processes; Scanning electron microscopy; Strain; Strain rate; Structural steels; 低周疲劳; 低应变速率; 应变能密度; 循环应力响应; 疲劳寿命; 疲劳行为; 高应变速率; 高强度结构钢
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1016/S1006-706X(13)60126-0

The low cycle fatigue （LCF） behavior of a high-strength structural steel was investigated in the strain rate range of 4×10^-6 -0.12 s^-1 （0. 001-3 Hz） under constant total strain （±1%） control. The cyclic stress response at all strain rates exhibited behavior of rapid softening in the early stage of fatigue life and subsequent saturation up to failure. It was found that the stress amplitude, the plastic strain amplitude, the plastic strain energy density and the fatigue life depend mainly on the strain rate. The strain rate of 0. 012 s-1 was found as a transition point where the LCF of the steel showed different behavior from low strain rate to high strain rate. The relationship between the time to failure and strain rate was expressed well by a power law relation. The fracture surfaces of the fatigue sam-ples were characterized by using a scanning electron microscope （SEM） and the fracture mechanisms were discussed in terms of time-dependent deformation of the steel.