The Theory of Critical Distances to estimate lifetime of notched components subjected to variable amplitude uniaxial fatigue loading

Susmel, Luca; Taylor, David

doi:10.1016/j.ijfatigue.2011.01.012

Cited by 84 publications

(52 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5(a). The tested notched specimens had gross diameter of 12 mm and net diameter varying in the range of 9.15-9.32 mm, with a root radius equal to 0.225 mm, 1.2 mm, and to 3 mm, resulting in an axial linear-elastic net stress concentration factor, Kt, of 4.42, 2.20, and 1.66, respectively [17].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Estimating Lifetime of Notched Components Subjected to Variable Amplitude Fatigue Loading According to the Elastoplastic Theory of Critical Distances

Susmel

Taylor

2015

Journal of Engineering Materials and Technology

Self Cite

View full text Add to dashboard Cite

The present paper is concerned with the use of the elastoplastic theory of critical distances (TCD) to perform the fatigue assessment of notched components subjected to in-service variable amplitude (VA) fatigue loading. The elastoplastic TCD takes as its starting point the assumption that the detrimental effect of stress!strain concentrators of any kind can efficiently be taken into account by directly postprocessing the entire elasto plastic stress!strain field in the vicinity of the notch apex. Thanks to its specific features, the TCD can be formalized in different ways by simply changing size and geometrical features of the domain used to calculate the required effective stress. The so-called point method (PM) is the simplest form in which this theory can be applied. This formalization of the TCD postulates that the elastoplastic stress!strain state to be used to estimate fatigue damage has to be determined at a given distance from the tip of the notch being assessed. According to the TCD's philosophy, such a distance is treated as a fatigue property. Therefore, given the material, this critical length does not change as either the features of the assessed stress!strain concentrator or the profile of the investigated load ing path vary. In the present study, the above design strategy is attempted to be used to estimate lifetime of notched component subjected to VA loading, the required critical dis tance being determined under constant amplitude (CA) loading. The accuracy and reli ability of the devised approach were checked by using a number of experimental results generated by testing, under both concave upward and concave downward spectra, notched samples containing geometrical features having a different sharpness. Such a validation exercise allowed us to prove that the elastoplastic TCD, used in the form of the PM, is highly accurate in estimating fatigue damage also in notched components subjected to in-service VA loading.

show abstract

Section: Methodsmentioning

confidence: 99%

“…1(a)), the TCD, applied in the form of the PM, allows fa tigue lifetime to be predicted with a level of accuracy which is not affected by the geometrical features of the assessed notch ( Fig. 1(b)) [17],…”

mentioning

confidence: 99%

Estimating Lifetime of Notched Components Subjected to Variable Amplitude Fatigue Loading According to the Elastoplastic Theory of Critical Distances

Susmel

Taylor

2015

Journal of Engineering Materials and Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…The daily variation of the internal pressure was described through two different load spectra each containing 1000 cycles. A concave upwards spectrum p i _CUS was determined by considering a conventional Rayleigh distribution [64], whereas a concave downwards spectrum p i _CDS was derived from those usually employed to 24 investigate the damaging effect of cycles of low stress amplitude [65]. In the present validation exercise, spectra p i _CUS and p i _CDS were assumed to summarise two appreciably different, but potentially realistic daily variations of the internal pressure that are significant from a fatigue damage point of view.…”

Section: Some Realistic Examplesmentioning

confidence: 99%

Investigating in-service failures of water pipes from a multiaxial notch fatigue point of view: A conceptual study

Brevis

Susmel

Boxall

2014

Proceedings of the Institution of Mechanical Engineers, Part C:

View full text Add to dashboard Cite

In ve s tigatin g in -sFinally, by taking as reference information the number of years for a blowout hole to form, the proposed approach is used to show how the lifetime of grey cast iron pipes can be remarkably shortened by fatigue. Ke yw o rd s :Water pipes, Multiaxial Notch Fatigue, Pitting, In-service lifetime IN TROD U CTIONThe secure supply of safe potable water is fundamental to society, for public health andwellbeing. Yet we distribute this vital product through an ageing, undervalued, buried infrastructure. Failures of water distribution systems do occur, including both catastrophic

show abstract

“…The concept of the MTS criterion is, in fact, the same with that of the point method in the theory of critical distances (TCD). The TCD has been originally proposed by Susmel and Taylor and utilized systematically to assess brittle fracture [45], ductile rupture [46] and fatigue damage [47] in notched components.…”

Section: Introductionmentioning

confidence: 99%

Combined tension–shear fracture analysis of V-notches with end holes

et al. 2015

View full text Add to dashboard Cite

In the present research, two stress-based failure criteria were proposed to predict brittle fracture in components containing V-notches with end holes (VO-notches) under mixed mode I/II loading. The first criterion, called VO-MTS, was an extension of the maximum tangential stress (MTS) criterion, and the second one, called VO-MS, was developed based on the mean stress (MS) failure concept. Two different groups of critical distances were utilized in the predictions. The first group was equal to the critical distances for sharp crack, and the second one was computed by using the mode I fracture test results on notched specimens. To verify the criteria, the theoretical fracture curves were compared with numerous experimental results gathered from 108 new brittle fracture tests performed on the Brazilian disk specimens weakened by central V-notches with end holes and made of PMMA under mode I and mixed mode I/II loadings. It was found that both the criteria provide very good predictions to the experimental results for different mode mixity ratios. Also, found in this research was that the curves are almost independent of the critical distance groups, meaning that one can simply utilize the critical distances of sharp crack in both the VO-MTS and the VO-MS criteria without requiring performing mode I VO-notch fracture experiments. List of symbolsCTSN Compact-tension-shear-notch CZM Cohesive zone model d Total slit length in the VO-BD specimen D Diameter of the VO-BD specimen d c Critical distance of the MS criterion for sharp cracks d c,vo Critical distance of the MS criterion for VO-notch E Young's modulus ERNFT Effective relative notch fracture toughness FE Finite element FFM Finite fracture mechanics FNR Fictitious notch radius K vo eff Effective relative notch fracture toughness K IC Plane-strain fracture toughness of material K vo I Mode I notch stress intensity factor

show abstract

The Theory of Critical Distances to estimate lifetime of notched components subjected to variable amplitude uniaxial fatigue loading

Cited by 84 publications

References 26 publications

Estimating Lifetime of Notched Components Subjected to Variable Amplitude Fatigue Loading According to the Elastoplastic Theory of Critical Distances

Estimating Lifetime of Notched Components Subjected to Variable Amplitude Fatigue Loading According to the Elastoplastic Theory of Critical Distances

Investigating in-service failures of water pipes from a multiaxial notch fatigue point of view: A conceptual study

Combined tension–shear fracture analysis of V-notches with end holes

Contact Info

Product

Resources

About