A multiaxial high-cycle fatigue life evaluation model for notched structural components

165

Notch features including holes, fillets, shoulders, and grooves commonly exist in engineering components. When subjected to external loads, these geometrical discontinuities generally act as stress raisers and thus present significant influences on the component strength and life, which are more remarkable under complex loading paths. Accordingly, numerous theories and approaches have been developed to address notch effects in metal fatigue as well as damage modelling and life predictions, which aim to provide theoretical support for structural optimal design and integrity evaluation. However, most of them are self‐styled or focus on specific objects, which limits their engineering applicability. This review recalls recent developments and achievements in notch fatigue modelling and analysis of metals. In particular, four commonly used methods for fatigue evaluation of metallic notched components/structures are summarized and elaborated, namely, nominal stress approaches, local stress‐strain approaches, and critical distance theories and weighting control parameters‐based approaches, which intend to provide a reference for further research on notch fatigue analysis and promote the integration and/or development among different approaches for practice.

τ_{R} = \frac{1}{V} \int f ((), τ) italicdv,

σ_{n, FI} = \frac{1}{V} \int f ((), σ_{n}) italicdv .

…”

Section: Weighting Control Parameters–based Approachesmentioning

confidence: 99%

Recent advances on notch effects in metal fatigue: A review

Liao

Zhu

Correia

et al. 2020

165

“…23,24,[27][28][29] However, most of the multiaxial fatigue damage models include additional material constants, which make them inconvenient for practical engineering application. 23,24,[27][28][29] However, most of the multiaxial fatigue damage models include additional material constants, which make them inconvenient for practical engineering application.…”

Section: Multiaxial Fatigue Damage Calculationmentioning

confidence: 99%

“…Many multiaxial fatigue damage models, which are based on the critical plane concept, have been presented. 23,24,[27][28][29] However, most of the multiaxial fatigue damage models include additional material constants, which make them inconvenient for practical engineering application. Shang and Wang 30 proposed a multiaxial fatigue damage model, in which the normal strain excursion ε * n À Á between adjacent turning points of the largest shear strain and the largest shear strain amplitude (Δγ max /2) in association with the critical plane are considered as 2 parameters controlling multiaxial fatigue damage.…”

Section: Multiaxial Fatigue Damage Calculationmentioning

confidence: 99%

Multiaxial notch fatigue life prediction based on pseudo stress correction and finite element analysis under variable amplitude loading

Tao

Shang

Sun

et al. 2018

A new computational methodology is proposed for fatigue life prediction of notched components subjected to variable amplitude multiaxial loading. In the proposed methodology, an estimation method of non‐proportionality factor (F) proposed by authors in the case of constant amplitude multiaxial loading is extended and applied to variable amplitude multiaxial loading by using Wang‐Brown's reversal counting approach. The pseudo stress correction method integrated with linear elastic finite element analysis is utilized to calculate the local elastic‐plastic stress and strain responses at the notch root. For whole local strain history, the plane with weight‐averaged maximum shear strain range is defined as the critical plane in this study. Based on the defined critical plane, a multiaxial fatigue damage model combined with Miner's linear cumulative damage law is used to predict fatigue life. The experimentally obtained fatigue data for 7050‐T7451 aluminium alloy notched shaft specimens under constant and variable amplitude multiaxial loadings are used to verify the proposed methodology and equivalent strain‐based methodology. The results show that the proposed methodology is superior to equivalent strain‐based methodology.

“…Therefore, several nonlocal approaches have been put forward to interpret the notch effect on the fatigue lifetime. [50][51][52][53] The common strategy is the CDTs, in which the PM and the LM can be formalized as…”

Section: Theories Of Critical Distancementioning

confidence: 99%

Evaluation of notch size effect on LCF life of TA19 specimens based on the stress gradient modified critical distance method

Wang

Liu

et al. 2018

In the present study, the stress gradient modified critical distance method is proposed to predict the low‐cycle fatigue lifetime of notched TA19 specimens by introducing a weight function of relative stress gradient into conventional critical distance theories. The accuracy and reliability of the proposed method were validated based on the experimental data by performing low‐cycle fatigue tests on smooth bar TA19 specimens as well as geometrically similar plate specimens containing a bore hole (BHP). Predicted results demonstrate that the mean absolute errors for entire tested specimens using the stress gradient modified critical distance method on the basis of the point method and the line method are 7.49% and 7.41% respectively. Furthermore, the fatigue striation width at the fracture surface was determined by scanning electronic microscope observations to examine the stress gradient effect on the crack growth rate.