A new effective stress intensity factor approach to determine thickness-independent fatigue crack growth rate curves

Calvín, Giovanna; Escalero, Mikel; Zabala, Haritz; Muñiz‐Calvente, Miguel

doi:10.1016/j.tafmec.2022.103505

Cited by 7 publications

(2 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The stress intensity factor, a central component in linear elastic fracture mechanics, has been a challenging problem to solve [19]. This difficulty arises from the singular stress at the crack tip of linear elastic materials, which becomes increasingly intense as the distance to the tip decreases and ultimately leads to nonconvergence in calculation results [20].…”

Section: Introductionmentioning

confidence: 99%

Model Development of Stress Intensity Factor on 7057T6 Aluminum Alloy Using Extended Finite Element Method

et al. 2023

View full text Add to dashboard Cite

The stress intensity factor represents a vital parameter within the realm of linear elastic fracture mechanics. It acts as the cornerstone in determining crack propagation and evaluating damage tolerance. However, calculating this factor is a complex task. To surmount this challenge, models of the stress intensity factor for both edge and center cracks were developed using the extended finite element method. The result of this effort is the ability to calculate the stress intensity factor at the crack tip under different loads and normalized crack lengths. The accuracy of these calculations was confirmed by comparing them to results from the NASGRO method, and the optimal mesh sizes for both the crack elements and overall units were established. Further analysis, conducted through MATLAB’s regression analysis, led to the development of an empirical model. This model was found to be both simple and reliable, making it an ideal tool for engineering applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Model Development of Stress Intensity Factor on 7057T6 Aluminum Alloy Using Extended Finite Element Method

et al. 2023

View full text Add to dashboard Cite

show abstract

“…9,10 However, the distribution of strain at the surface of a thick specimen can differ significantly from the distribution at the mid-thickness. Higher stress triaxiality occurs at this mid-thickness plane strain region, and since higher triaxiality normally favors crack growth in high-cycle fatigue, [11][12][13][14][15] this region may control the material's overall fatigue crack growth behavior. Secondly, these techniques only measure total strain, and it is not possible to isolate the elastic component of strain (i.e., the part that relates to the material's stress state) without additional assumptions.…”

Section: Introduction 1| Fatigue Crack Growth Rate and Stress Ratiomentioning

confidence: 99%

Subsurface fatigue crack tip strains in 7475‐T7351 aluminium alloy measured using stroboscopic neutron diffraction

Coules

Probert

Azuma

et al. 2023

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

Fatigue crack growth in thick‐section metals is typically controlled by an internal plane strain region where strong triaxial constraint of the crack tip occurs. However, the crack tip stress state in this region is challenging to measure. We have used neutron diffraction to study the plane strain section of fatigue crack tips in situ. A stroboscopic form of neutron diffraction using a moving frame‐of‐reference was developed to measure crack tip strains as a function of phase in the fatigue loading cycle without interrupting the cyclic load. Using point measurements of near‐tip strain in 7475‐T7351 aluminium alloy in conjunction with finite element analysis, we can estimate the extent of the crack tip plastic zone, verifying that it is small for this material and set of loading conditions.

show abstract

Misconception of the Use of 2D Plane Stress Solutions for Free Surfaces of Cracked Bodies and Its Significance for Full Field Measurement Techniques

Vojtek,

Kubíček,

Pokorný

et al. 2024

Adv Eng Mater

View full text Add to dashboard Cite

Although 2D fracture mechanics solutions have been successfully applied, many analyses are affected by the wrong presumption of the 2D plane stress state at the free surface intersected by a crack front. The significance of this presumption and the related confusion have grown rapidly with the progress of strain field measurement techniques, such as the digital image correlation. The article demonstrates this wrong presumption on two of the most commonly measured and studied entities, which are the plastic zone in front of the crack tip and the crack tip opening displacement. 3D stress and strain solution is necessary to be performed. A realistic crack front curvature is required to be considered. Only such solutions can be used for comparison with the experimentally obtained strain fields. Other solutions are wrong and can bring confusion, wrong conclusions about material behavior, and slow down the progress in the field of fracture mechanics due to the incompatibility of the presumed stress state and the stress state present in experiments.

show abstract

A new effective stress intensity factor approach to determine thickness-independent fatigue crack growth rate curves

Cited by 7 publications

References 30 publications

Model Development of Stress Intensity Factor on 7057T6 Aluminum Alloy Using Extended Finite Element Method

Model Development of Stress Intensity Factor on 7057T6 Aluminum Alloy Using Extended Finite Element Method

Subsurface fatigue crack tip strains in 7475‐T7351 aluminium alloy measured using stroboscopic neutron diffraction

Misconception of the Use of 2D Plane Stress Solutions for Free Surfaces of Cracked Bodies and Its Significance for Full Field Measurement Techniques

Contact Info

Product

Resources

About