Comparison of TCD and SED methods in fatigue lifetime assessment

Abstract

This paper assesses the accuracy and reliability of the Theory of Critical Distances (TCD) and the Strain Energy Density (SED) approach in estimating the lifetime of plain and notched specimens subjected to cyclic loading. To validate the two approaches for plain and notched components under uniaxial and multiaxial fatigue loading, a large bulk of experimental data taken from the literature were re-analyzed, with the state variables, i.e. the stress distributions and the strain energy density, being calculated via Finite Element (FE) approach. The results obtained demonstrate that both the TCD and the SED approach can provide highly accurate fatigue life estimation. In addition, the two adopted approaches require few computational efforts and experimental data to be implemented and used for fatigue design in situations of practical interest.

Fatigue behaviour of a multiphase medium carbon steel: Comparison between ferrite/pearlite and tempered microstructures

“…In addition, the S‐N curves of both the AC and QT steels after fatigue experiments are presented in Figure 4. Because the fatigue result is always characterized by physiological scattering, the experimental data must be carefully post‐processed to determine a reliable reference fatigue curve 18 . Figure 4 presents three different straight trend lines, which correspond to three different values of the probability of survival, Ps (i.e.…”

Recent advances on notch effects in metal fatigue: A review

“…Specifically, it is assumed that both the smooth and notched specimens accumulate equal damage and show identical number of cycles to failure if their stress‐strain responses at the initiation sites are the same; moreover, fatigue failure happens when the total strain energy density (sum of the plastic and the positive elastic components) at the initiation regions reaches a threshold value. In general, it presents excellent accuracy in fatigue lifetime assessment of plain and notched components under multiaxial loadings . Moreover, this approach can also be extended to variable amplitude fatigue loading cases…”

“…In general, it presents excellent accuracy in fatigue lifetime assessment of plain and notched components under multiaxial loadings. 143 Moreover, this approach can also be extended to variable amplitude fatigue loading cases. 144 Inspired by the SFI and total strain energy densitybased models, Liao and Zhu 128 developed an energy field intensity (EFI) approach for multiaxial notch fatigue analysis, as is schematized in Figure 16.…”

Physical characteristics of concrete, essential in design of fracture‐resistant, dynamically loaded reinforced concrete structures

“…Effects of material fatigue, caused by dynamic load resulting in the occurrence of variable stresses, manifest themselves in the possibility of destruction of the loaded element at stresses lower than those needed for the destruction of the same element, but loaded statically, eg, Hu et al In the case of dynamic loads, the calculated material strength depends on the number of cycles of stress changes, the value of the initial static stress, on which stresses will overlap, and the ratio of minimum and maximum stresses. An additional factor affecting the strength is the presence of the so‐called notches, which may cause stress concentration.…”