Evaluation of fatigue-crack growth rates by polynomial curve fitting

Davies, K. B.; Feddersen, C. E.

doi:10.1007/bf00035965

Cited by 20 publications

(4 citation statements)

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“…Given the demonstrated performance of polynomial fitting for depicting fatigue degradation 27,28 , a secondorder polynomial function is adopted to map the l-th CL and the number of load cycles, as follows 𝑧 𝑙,𝑘 = 𝑝 1,𝑙,𝑘 𝑁 𝑘 2 + 𝑝 2,𝑙,𝑘 𝑁 𝑘 + 𝑝 3,𝑙,𝑘…”

Section: Modeling and Pf Parametersmentioning

confidence: 99%

Particle filter-based delamination shape prediction in composites subjected to fatigue loading

Cadini

Chiachío

et al. 2022

Structural Health Monitoring

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Modeling generic size features of delamination, such as area or length, has long been considered in the literature for damage prognosis in composites through specific models describing damage state evolution with load cycles or time. However, the delamination shape has never been considered, despite that it holds important information for damage diagnosis and prognosis, including the delamination area, its center, and perimeter, useful for structural safety evaluation. In this context, this paper develops a novel particle filter (PF)-based framework for delamination shape prediction. To this end, the delamination image is discretized by a mesh, where control points are defined as intersections between the grid lines and the perimeter of the delamination. A parametric data-driven function maps each point position as a function of the load cycles and is initially fitted on a sample test. Then, a PF is independently implemented for each node whereby to predict their future positions along the mesh lines, thus allowing delamination shape progression estimates. The new framework is demonstrated with reference to experimental tests of fatigue delamination growth in composite panels with ultrasonics C-scan monitoring.

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Section: Modeling and Pf Parametersmentioning

confidence: 99%

Particle filter-based delamination shape prediction in composites subjected to fatigue loading

Cadini

Chiachío

et al. 2022

Structural Health Monitoring

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“…( 9), where values of the maximum (σ max ) and minimum (σ min ) stresses are used to calculate K max and K min by Eq. (8).…”

Section: Determine Paris Law Constantsmentioning

confidence: 99%

“…In recent decades, extensive studies have been published to investigate the mechanisms of fatigue crack in metallic materials [1,2,3,4,5,6,7]. Several kinds of functions or laws have been proposed to describe and predict the rule of fatigue crack propagation including polynomial [8] , exponential [9,10], power functions [11]. A popular model for fatigue crack propagation is the Paris law in which the relationship between cyclic crack growth rate da/dN and the stress intensity factor ∆K is described by a power function [12].…”

Section: Introductionmentioning

confidence: 99%

Fatigue crack propagation in carbon steel using RVE based model

Cheng

Liu

2021

Preprint

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A representative volume element (RVE) based multi-scale method is proposed to investigate the mechanism of fatigue crack propagation by the molecular dynamics (MD) and the extended finite element methods(XFEM) in this study. An atomic model of carbon steel plate is built to study the behavior of fatigue crack at the micro scale by MD method. Then the RVE model for fatigue crack propagation should be built by fitting the data which was obtained from the MD result with the Paris law model. Moreover, the effect of micro-structural defects including interstitial atoms, vacancies have also been considered in this study. The results indicate that the micro-structural defects can deeply influence the values of Paris law constants and the life of the specimen can be evaluated by the proposed method.

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“…In theory, the use of linear elastic fracture mechanics concepts has been proved with considerable success in interpreting fatigue crack growth data. Many propagation rate laws have been proposed, including polynomial [1], exponential [2], power functions [3]. One of the most widely accepted in the Paris-Erdogan [4] fatigue crack growth law is:…”

Section: Introductionmentioning

confidence: 99%

Evolution of Crack Propagation Rate in Notched Specimens Using XFEM Method under Bending Load Condition

Zergot¹,

Moussaoui²,

Hachi³

2022

ACSM

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The crack initiation and propagation often occur in structures subjected to fatigue loads and their privileged sites it is the geometric discontinuity in particular the notches. The geometric configuration of the notches always leads to disturbances of stress fields in the vicinity of the notch end as a consequence of the effects on the crack initiation site and on the crack rate. The present study is interested to the evolution of crack speed propagation in the notched specimens subjected to bending. The specimens chosen are made of PMMA material containing two opposite notches U or V that presented two different parameters, a radius for U-notch and angle for V-notch. The variations taken into account for the sharp notches (V-notch) going from the small angle to the large angle, which are 30°; 45°, 90°, and 140°, and for blunt notches (U-notch) the radius takes the different values 0.5, 1, 1.5, and 2 mm. The fracture brittle behavior adapted to this material led to predict the Fatigue crack growth using a modified form of Paris’s law with the equivalent stress intensity factor (ΔKeq) relying on extended finite element method (XFEM) in order to follow the interaction between the notch and the crack on one side and study the evolution of crack growth rate to another side. The variations, which brought to these parameters entailed an influence on the crack propagation speed, which was born at the end of notch of component as well as the variations of equivalent notch intensity stress factors (ΔKeq). The variations made to the parameters of notches have a huge influence on the crack propagation rate.

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Evaluation of fatigue-crack growth rates by polynomial curve fitting

Cited by 20 publications

References 0 publications

Particle filter-based delamination shape prediction in composites subjected to fatigue loading

Particle filter-based delamination shape prediction in composites subjected to fatigue loading

Fatigue crack propagation in carbon steel using RVE based model

Evolution of Crack Propagation Rate in Notched Specimens Using XFEM Method under Bending Load Condition

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