Fatigue crack growth in cruciform welded joints: Influence of residual stresses and of the weld toe geometry

Ngoula, Desiré Tchoffo; Beier, Heinz Thomas; Vormwald, Michael

doi:10.1016/j.ijfatigue.2016.09.020

Cited by 60 publications

(27 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to capture crack closure effects [12,18,19] in the FE-model, contact boundary conditions have to be defined between crack faces. The contact opening displacements of all the crack face nodes were monitored during the cyclic loading for the determination of the crack closure time, t cl .…”

Section: Effective Cyclic J-integralmentioning

confidence: 99%

“…Only two load cycles were applied for every crack length configuration in order to restrict the FEcalculation time. In addition, two load cycles were applied before the first node release so that the residual stress relaxation/redistribution can be taken into account [18,23]. The crack extension was done at positive nominal stress (in order to satisfy the physical requirement that only an opened crack can propagate) and the increase in crack depth ∆ was chosen to be 0,05 mm for semi-circular cracks (3D calculations) and 0,01 mm for continuous cracks (modelled by using 2D models) respectively.…”

Section: Validation Examplementioning

confidence: 99%

“…The specimen geometry, material parameters, boundary conditions (including the gradual definition of contacts between the crack faces) and applied loads are needed here. If residual stresses are to be considered, they are inserted by using a procedure described by the authors in [18,23].…”

Section: Algorithm Of Crack Growth Simulationmentioning

confidence: 99%

“…The residual stress field that arises from the welding process can have a significant influence on the fatigue life [1,18]. Tensile and compressive residual stresses were generated in the joint by means of structural calculations (see [24] for more details).…”

Section: Influence Of Residual Stresses On the Calculated Fatigue Livesmentioning

confidence: 99%

See 3 more Smart Citations

Short fatigue crack growth in welded joints described by the effective cyclic J-integral

Ngoula

Vormwald

2018

MATEC Web Conf.

View full text Add to dashboard Cite

Abstract. The purpose of the present contribution is to predict the fatigue life of welded joints by using the effective cyclic J-integral as crack driving force. The plasticity induced crack closure effects and the effects of welding residual stresses are taken into consideration. Here, the fatigue life is regarded as period of short fatigue crack growth. The node release technique is used to perform finite element based crack growth analyses. For fatigue lives calculations, the effective cyclic J-integral is employed in a relation similar to the Paris (crack growth) equation. For this purpose, a specific code was written for the determination of the effective cyclic J-integral for various lifetime relevant crack lengths. The effects of welding residual stresses on the crack driving force and the calculated fatigue lives are investigated. Results reveal that the influence of residual stresses can be neglected only for large load amplitudes. Finally, the predicted fatigue lives are compared with experimental data: a good accordance between both results is achieved.

show abstract

Section: Effective Cyclic J-integralmentioning

confidence: 99%

Section: Validation Examplementioning

confidence: 99%

Section: Algorithm Of Crack Growth Simulationmentioning

confidence: 99%

Section: Influence Of Residual Stresses On the Calculated Fatigue Livesmentioning

confidence: 99%

See 2 more Smart Citations

Short fatigue crack growth in welded joints described by the effective cyclic J-integral

Ngoula

Vormwald

2018

MATEC Web Conf.

View full text Add to dashboard Cite

show abstract

“…For cruciform fillet welded joints which are the subject of this work, the external stress concentrators are found on the at the intersection between the base and the filler material, areas named "weld toe areas" in the specialty literature and on the other hand at the root of the welding, as shown in figure 1. These "weld toe areas" in the case of variable loads are very dangerous, and from there, are initiated many cracks that can sometimes have catastrophic effects on the structure [16,17]. In figure 1, we marked with K the cords of the welding, with R/r the radius of the connection between the filler and the base material, s is the thickness of the plates, σmax is the maximum stress, σn is the nominal stress and F is the force the force acting on the weld joint.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Rehabilitation Techniques on Static and Variabile Loads in Case of a HSLA Steel Samples

Babiş¹,

Solomon²,

Iacobescu³

et al. 2018

Preprint

View full text Add to dashboard Cite

Abstract:There are many welded structures in the world such as bridges and viaducts that are subject to fatigue. These structures, generally made of non-alloy or low-alloy steels, have been put into operation some of them with many years ago and have accumulated a large number of variable load cycles over the time. For this reason the occurrence of fatigue phenomenon is inevitable and consists in the occurrence of failures at stresses applied to the structure, below the yield limit of the material. These stresses under the static loads would not cause the failures to appear..This paper will investigate whether two reconditioning techniques "weld toe grinding" and "WIG remelting weld toe", influences favorably the behavior of welded structures made from HSLA steel, in static and variable loads and therefore if the application of these techniques is justified in both cases. In the paper will be presented the chemical composition and mechanical properties of the base and filler materials, micro and macrostructures, graphics with the variation of microhardness, static and fatigue tensile tests will be performed, and it will be rised durability curve in case of fatigue tests.

show abstract

Fatigue of welded joints described by elastic‐plastic fracture mechanics

2018

View full text Add to dashboard Cite

The fatigue life of welded joints is calculated using the effective cyclic J-integral as crack driving force. The plasticity induced crack closure effect is taken into consideration. Here, the fatigue life is regarded as period of short fatigue crack growth. Two and three dimensional finite element models, with cracks as initial defects, are constructed for this purpose. The finite element based crack growth analyses were performed by using the node release technique in combination with the finite element program AB-AQUS. For fatigue life calculations, the effective cyclic J-integral was employed in a relation similar to the Paris (crack growth) equation. For this purpose, a Python code was written for the determination of the crack driving force for various relevant crack lengths. The calculated fatigue lives were compared with experimental data and a good accordance between both results was achieved. Schwingfestigkeit von Schweißverbindungen beschrieben mitHilfe der elastisch-plastischen Bruchmechanik. Die Schwingfestigkeit von Schweißverbindungen wird unter Verwendung des effektiven zyklischen J-Integrals als risstreibende Kraft berechnet. Plastizitätsinduzierte Rissschließeffekte werden dabei berücksichtigt. Hierzu werden ebene und räumliche, mit rissartigen Imperfektionen versehene, Finite-Elemente-Modelle erstellt. Die Simulation des Ermüdungsrisswachstums erfolgt unter Anwendung des Node-Release-Verfahrens mit dem kommerziellen FE-Programm ABAQUS. Zur Berechnung der Lebensdauer wurde das effektive zyklische J-Integral in eine Relation ähnlich der Rissfortschrittsgleichung nach Paris eingesetzt. Zu diesem Zweck wurde ein Algorithmus geschrieben, um die risstreibende Kraft für verschiedene lebensdauerrelevante Risslängen zu bestimmen. Die damit berechneten Lebensdauern für technischen Anriss wurden mit experimentellen Daten verglichen: Berechnete und experimentell bestimmte Lebensdauern stimmten gut überein.

show abstract

Fatigue crack growth in cruciform welded joints: Influence of residual stresses and of the weld toe geometry

Cited by 60 publications

References 35 publications

Short fatigue crack growth in welded joints described by the effective cyclic J-integral

Short fatigue crack growth in welded joints described by the effective cyclic J-integral

The Influence of Rehabilitation Techniques on Static and Variabile Loads in Case of a HSLA Steel Samples

Fatigue of welded joints described by elastic‐plastic fracture mechanics

Contact Info

Product

Resources

About