Fatigue life prediction model of metallic materials considering crack propagation and closure effect

Abstract

To consider the effect of crack closure on the mechanical properties of metals, the fatigue life of metal specimens is predicted based on energy dissipation model. The main feature of the model consists in considering the relationship between the total failure energy and the energy density increment. The total failure energy model considers the fatigue crack size and stress amplitude. It is assumed the energy density increment gradually decreases and tends to be stable. The influence of crack closure effect is considered. According to the law of metal fatigue characteristics, a new mathematical model for predicting fatigue life is established. Keywords Energy increment • Metallic material • Crack closure effect • Fatigue life List of symbols b Fatigue strength exponent c The fatigue ductility exponent Δ Stress range a Maximum tensile stress a c Critical crack size a 0 Initial crack size n Strain hardening exponent n ′ Cyclic strain hardening exponent f Fracture ductility ′ f Cyclic fatigue ductility coefficient Δ p Plastic strain range Δ pZ Plastic strain increment under equivalent stress increment Equivalent strain increment parameter W p Plastic strain energy ′ f Cyclic fatigue strength coefficient W One-cycle plastic strain energy increment K ′ Cyclic stress intensity coefficient W pf Total failure energy b Ultimate tensile strength K theff Effective initial stress intensity factor K I

Evaluation and prediction of material fatigue characteristics under impact loads: review and prospects

“…This method is used to explain the Palmgren Miner rule from the physical point of view, and it is illustrated with a practical double-block loading instance. It develops a simple fatigue life prediction method, also takes into account the influence of the overload block (Wu et al. , 2020; You et al.…”

Fatigue life prediction of gasoline storage tank considering varying current density and weld stress

“…However, the pressures of different liquid levels in large-scale liquid storage tanks are completely different, and there is no pressure on the upper surface, so the thin-walled cylinder method is not suitable for calculating the stress of large-scale liquid storage tanks. [28][29][30] In this paper, the stress state at the crack is studied based on the combined cylinder method.…”

Fracture Areas Quantitative Investigating of Bending-Torsion Fatigued Low-Alloy High-Strength Steel

“…Surface flaws and internal cracks play a central role in the failure of materials. Therefore, fracture mechanisms are studied very widely, e.g., Wu et al [19] presented a fatigue life prediction model considering crack propagation and closure effect. Additionally, Derpeński et al [20] have taken up fracture tests of axisymmetric specimens with circumferential notches under elevated temperature.…”