Fatigue crack growth of aluminium alloy 7075-T651 under proportional and non-proportional mixed mode I and II loads

Yu, Xiaobo; Li, Ling; Proust, Gwénaëlle

doi:10.1016/j.engfracmech.2017.01.008

Cited by 24 publications

(13 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The evaluation of an equivalent SIF only makes sense when there is more than one SIF mode. As reported in literature crack growth can occur, besides pure mode I, only in mode III [31], mode I and III [32], mode I and II [27] [74] and modes I, II, and III combined [30,80]. The holed C(T) specimen did not develop visible out-of-plane displacements other than the ones in the very near zone, as described by He and Kotouzov [62].…”

Section: Analysis Of Equivalent Sif and Equivalent Sif Rangesupporting

confidence: 67%

Linear Elastic Fracture Mechanics Analysis of Fatigue Crack Growth Under Complex Loading Using the Digital Image Correlation Technique

Díaz¹

View full text Add to dashboard Cite

Fatigue crack propagation assessment includes identifying the crack direction, knowing the equivalent Stress Intensity Factor (SIF) range, determining a crack length growth rate per number of cycles (da/dN), and establishing a crack propagation rule connecting the equivalent SIF and da/dN rate, such as a Paris type of rule. When mixed and non-proportional loading occur, those parameters are not fully understood yet. This thesis deals with some of the variables that influence crack propagation under non-proportional mixed mode loading. The Digital Image Correlation (DIC) technique was used to acquire images of test specimens subjected to cyclic proportional and non-proportional loading. Two types of specimen samples were used. Firstly, two different plate test specimens were tested; a disk compact tension (DCT), and a modified compact tension, C(T). They were subjected cyclic loading inducing crack opening mode I or proportional crack opening modes I and II. Secondly, the previously and elsewhere acquired DIC data for five thin tubes subject to cyclic loading were analyzed. The thin tubes had prefabricated slit-notches from which fatigue cracks initiated and propagated. Those five thin tubes were subjected to different cases of proportional and non-proportional loading. One tube specimen was exposed to axial loading and presented mode I crack opening. The other four were subjected to torsion loading or mixed axial-torsional loading and exhibited all three I, II and III crack-opening modes. The experimentally acquired DIC displacement fields were processed to independently calculate SIF for each existing opening mode using linear elastic fracture mechanics (LEFM) formulations. One formulation used full

show abstract

Section: Analysis Of Equivalent Sif and Equivalent Sif Rangesupporting

confidence: 67%

Linear Elastic Fracture Mechanics Analysis of Fatigue Crack Growth Under Complex Loading Using the Digital Image Correlation Technique

Díaz¹

View full text Add to dashboard Cite

show abstract

“…Some cracks opening mode will be governed by mode II and will behave according to the Maximum Shear Stress (MSS) Criterion. Yu et al [18] have compared the crack propagation in mode I and mode II, and proposed the basis for the implementation of the MTS and MSS criteria. Both have been implemented in the algorithm.…”

Section: Algorithm For Fatigue Crack Propagationmentioning

confidence: 99%

Algorithm for automatic fatigue crack growth simulation on welded high strength steels

Baptista

Infante²,

Marques³

2019

Frattura Ed Integrità Strutturale

View full text Add to dashboard Cite

Nowadays the demand for high strength steels is increasing. In order to design and develop high performance products, it is essential to understand the fatigue behavior of these materials. When considering welded components, the fatigue behavior is even more complex. The material parameters may change along the crack growth and mixed mode crack propagation may also occur. To assess welded high strength steel fatigue behavior, different welded CT specimens were tested. The Paris law material constants were obtained for the heat affected zone material. Fatigue crack growth life predictions were made using the obtained parameters and different automatic techniques. Previous work showed that the ABAQUS extended finite element method can predict fatigue crack growth, but as the implementation of the Paris law is not straight forward, to many conversions must be made and the results are too computer intensive. A simpler and more intuitive Python algorithm was developed, to enable the use of the experimental material parameters, to predict the crack propagation path. The obtain results show a good agreement with both the experimental Paris curves, and the analytical solution.

show abstract

“…To clarify the incipient direction of the crack path observed by Bold et al [8], Dahlin and Olsson [13] investigated several criteria while using the FEA approach; they concluded that a maximum tangential stress (MTS) range criterion based on an elasto-plastic stress field can appropriately predict the incipient crack growth direction in ductile metals. Yu et al [14] studied the FCG behavior in a thin-walled tubular specimen of aluminum alloy under non-proportional mixed mode I and II loading, showing that the FCG significantly differed from that under mode I or proportional mixed mode loading. Although they obtained a long and stable shear mode growth, they could not apply the commonly accepted MTS criterion in most of the non-proportional loading cases.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Crack Growth under Non-Proportional Mixed Mode Loading in Rail and Wheel Steel Part 1: Sequential Mode I and Mode II Loading

Akama

2019

Applied Sciences

View full text Add to dashboard Cite

Fatigue tests were performed to estimate the coplanar and branch crack growth rates on rail and wheel steel under non-proportional mixed mode I/II loading cycles simulating the load on rolling contact fatigue cracks; sequential and overlapping mode I and II loadings were applied to single cracks in the specimens. Long coplanar cracks were produced under certain loading conditions. The fracture surfaces observed by scanning electron microscopy and the finite element analysis results suggested that the growth was driven mainly by in-plane shear mode (i.e., mode II) loading. Crack branching likely occurred when the degree of overlap between these mode cycles increased, indicating that such degree enhancement leads to a relative increase of the maximum tangential stress range, based on an elasto–plastic stress field along the branch direction, compared to the maximum shear stress. Moreover, the crack growth rate decreased when the material strength increased because this made the crack tip displacements smaller. The branch crack growth rates could not be represented by a single crack growth law since the plastic zone size ahead of the crack tip increased with the shear part of the loading due to the T-stress, resulting in higher growth rates.

show abstract

Fatigue crack growth of aluminium alloy 7075-T651 under proportional and non-proportional mixed mode I and II loads

Cited by 24 publications

References 26 publications

Linear Elastic Fracture Mechanics Analysis of Fatigue Crack Growth Under Complex Loading Using the Digital Image Correlation Technique

Linear Elastic Fracture Mechanics Analysis of Fatigue Crack Growth Under Complex Loading Using the Digital Image Correlation Technique

Algorithm for automatic fatigue crack growth simulation on welded high strength steels

Fatigue Crack Growth under Non-Proportional Mixed Mode Loading in Rail and Wheel Steel Part 1: Sequential Mode I and Mode II Loading

Contact Info

Product

Resources

About