On the estimation of finite lifetime under fretting fatigue loading

Kouanga, C.T.; Jones, Justin Daniel; Revill, I.; Wormald, A.; Nowell, D.; Dwyer-Joyce, R. S.; Araújo, J.A.; Susmel, Luca

doi:10.1016/j.ijfatigue.2018.03.013

Cited by 18 publications

(6 citation statements)

References 60 publications

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“…It has been successfully used for a wide range of cases, including notches, holes, short cracks and contact problems. It has been applied to all classes of materials: recent examples include polymers [5] composites [6], rocks [7], welded joints [8] low-cycle fatigue [9] and fretting fatigue [10]. Within the general TCD approach there are several different methods, all of which require the definition of a material parameter with dimensions of length: the critical distance L. Stress-based methods involve the determination of a characteristic stress, defined as the stress at a given distance (L/2) from the notch root or averaged over a region ahead of the notch whose size depends on L. Stress-intensity based methods include the insertion of an imaginary crack (of length L) or the assumption of a step-wise mode of crack extension in which the step size is 2L [11].…”

Section: Introductionmentioning

confidence: 99%

The Theory of Critical Distances applied to multiscale toughening mechanisms

Taylor

2019

Engineering Fracture Mechanics

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The Theory of Critical Distances (TCD) is an approach used for predicting the effect of cracks and notches on fracture and fatigue behaviour. In recent years it has been successfully applied to a wide range of problems across all classes of materials. The approach relies on the identification of a material constant known as the critical distance, L, which can only be determined by fitting predictions to experimental data. It has been argued that L is related to the size of microstructural features which affect crack growth, but this argument becomes problematic in the presence of multiple toughening mechanisms operating at different scales. In the present work, this matter was approached through the use of thought experiments conducted on model microstructures. It was found that if two mechanisms operate at different length scales, then the use of the normal TCD approach is still possible, though accuracy is reduced and the value of L obtained falls between the length scales of the two mechanisms. A more sophisticated approach however can successfully identify two relevant L values and thus provide insights into the underlying mechanisms. A practical example is given: the analysis of short and long crack toughness data for bone, for which mechanisms at the hundred-micron and millimetre scales were successfully identified. Some general conclusions emerge about the effect of hierarchical toughening mechanisms: in particular it was found that the mechanisms operating at the small length scales may control the strength of the material but have relatively little effect on its toughness.

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Section: Introductionmentioning

confidence: 99%

The Theory of Critical Distances applied to multiscale toughening mechanisms

Taylor

2019

Engineering Fracture Mechanics

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“…TCD applicability field is not restricted to notched components: examples of its use are found in the study of fretting fatigue. 2,3 In this context, the so called "notch analogue" 2,3,28 is noteworthy: this term refers to similarities of stress states both around notches tip and contact surfaces in fretting fatigue. This is the starting point for applying the same fatigue concepts in two apparently different situations linked by the presence of a multiaxial stress state.…”

Section: Applications Of Tcdmentioning

confidence: 99%

“…This is the starting point for applying the same fatigue concepts in two apparently different situations linked by the presence of a multiaxial stress state. Indeed Kouanga et al 2 studied the crack initiation process in fretting fatigue loadings by using TCD. In this case, TCD showed to be able to predict finite lifetime in metals subjected to Constant Amplitude (CA) loads.…”

Section: Applications Of Tcdmentioning

confidence: 99%

“…It was introduced a scale length whose ability of predicting fatigue failure was widely proved. [1][2][3]13,15 Actually, explaining the meaning of this length is not straightforward. Thanks to FFM, L was related to crack growth discrete quanta but its correlation with fracture mechanism is not fully assessed.…”

Section: Remarks On Critical Distancementioning

confidence: 99%

“…Answering these questions is not trivial, however non-local methods proved to be suitable [1][2][3] when stress gradients are not negligible as it occurs for notched components.…”

Section: Introductionmentioning

confidence: 99%

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Theory of critical distances: A discussion on concepts and applications

Delprete

Maggio

Sesana

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Theory of Critical Distances (TCD) collects several methods adopted in failure prediction of components provided with stress concentration features. The idea of evaluating stress effect in a zone rather than in a single point was proposed decades ago but, only thanks to relatively recent works, TCD concepts showed to be a successful extension of Linear Elastic Fracture Mechanics (LEFM), able to assess strength and fatigue life. The increasing computational power has made Finite Element Method (FEM) widespread, hence stress fields can be easily extracted and used as input data for fatigue post-processing and durability analyses. In this scenario, TCD reveals as a powerful tool which, thanks to the introduction of a single material parameter (critical distance, [Formula: see text]), integrates classical fracture models by considering the presence of microscale phenomena acting in fracture process. In this sense, TCD behaves as a link between continuum mechanics and LEFM. Modalities and reasons for this connection to occur are interesting points of further investigations. Literature on TCD and its theoretical-experimental background is quite extended, nevertheless few industrial applications are available in literature to the best of authors’ knowledge. In this paper, an overview of concepts and applications related to TCD are reported highlighting the relevance of theoretical arguments in actual applications.

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Critical Plane and Critical Distance Approaches to Assess Damage Under Variable Amplitude Fretting Fatigue Loading

Kouanga

Nowell

Dwyer-Joyce

et al. 2022

Lecture Notes in Mechanical Engineering

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This paper summarises an attempt to formulate a design approach suitable for predicting the finite lifetime of mechanical assemblies subjected to constant/variable amplitude fretting fatigue loading. The proposed design methodology makes use of the Modified Wӧhler Curve Method (MWCM), applied in conjunction with the Theory of Critical Distance (TCD) and the Shear Stress-Maximum Variance Method (τ-MVM). In particular, the TCD (applied in the form of the Point Method) is used to take into account the damaging effect of the multiaxial stress gradients acting on the material in the vicinity of the contact region. The time-variable linear-elastic stress state at the critical point is then post-processed according to the MWCM which is a bi-parametrical criterion that estimates fatigue lifetime via the planes experiencing the maximum shear stress amplitude. Finally, the τ-MVM is used to calculate the stress quantities relative to the critical plane whose orientation is determined numerically by selecting the plane containing the direction experiencing the maximum variance of the resolved shear stress. Further, this direction is also used to perform the cycle counting by directly applying the classic Rain-Flow Method to post-process the resolved shear stress. The overall accuracy and reliability of the proposed approach is checked against a large number of new experimental results that were generated in the Sheffield Structures Laboratory under variable amplitude fretting fatigue loading.

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On the estimation of finite lifetime under fretting fatigue loading

Abstract: This is a repository copy of On the estimation of finite lifetime under fretting fatigue loading.

Cited by 18 publications

References 60 publications

The Theory of Critical Distances applied to multiscale toughening mechanisms

The Theory of Critical Distances applied to multiscale toughening mechanisms

Theory of critical distances: A discussion on concepts and applications

Critical Plane and Critical Distance Approaches to Assess Damage Under Variable Amplitude Fretting Fatigue Loading

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