scholarly journals Impact of the Weld Geometry on the Stress Intensity Factor of the Welded T-Joint Exposed to the Tensile Force and the Bending Moment

2015 ◽  
Vol 11 (2) ◽  
pp. 103-109
Author(s):  
Jelena M. Djoković ◽  
Ružica R. Nikolić ◽  
Ján Bujňák
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Tensile Force ◽  
Bending Moment ◽  
Linear Elastic ◽  
Weld Geometry ◽  
Axial Tensile ◽  
The Impact

Abstract In this paper it is analyzed the welded T-joint exposed to the axial tensile force and the bending moment, for determining the impact of the weld geometry on the fracture mechanics parameters. The stress intensity factor was calculated analytically, based on the concept of the linear elastic fracture mechanics (LEFM), by application of the Mathematica® programming routine. The presence of the weld was taken into account through the corresponding correction factors. The results show that increase of the size of the triangular welds leads to decrease of the stress intensity factor, while the SIF increases with increase of the welds’ width. The ratio of the two welded plates’ thicknesses shows that plate thicknesses do not exhibit significant influence on the stress intensity factor behavior.

Review of Technical Basis for ASME Code Section XI Appendix L

2020 ◽  
Author(s):  
Deepak S. Somasundaram ◽  
Dilip Dedhia ◽  
Do Jun Shim ◽  
Gary L. Stevens ◽  
Steven X. Xu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Crack Growth ◽  
Multiple Cracks ◽  
Single Crack ◽  
Flaw Tolerance ◽  
Asme Code ◽  
The Impact

Abstract Equivalent Single Crack (ESC) sizes are provided in ASME Code, Section XI, Nonmandatory Appendix L, Tables L-3210-1 (for ferritic piping) and L-3210-2 (for austenitic piping). These two tables define initial flaw aspect ratios for use in fatigue flaw tolerance evaluations. These ESC sizes were based on the results of probabilistic fracture mechanics (PFM) evaluations that determined the equivalent single crack size that resulted in the same probability of through-wall leakage as the case when multiple cracks are initiated and grown around the inner circumference of a pipe. The PFM software, pc-PRAISE, used for the evaluation of ESC sizes had fracture mechanics models based on available data and models in the early 2000s. The stress intensity factor solutions used in pc-PRAISE were generated for a pipe radius-to-thickness ratio, Ri/t, of 5, and used a root-mean-square (RMS) averaged methodology. And the crack growth model was based on NUREG/CR-2189, Volume 5. This paper presents the results of evaluations to calculate a limited number of ESC sizes using updated fracture mechanics models for stress intensity factor and fatigue crack growth rates. The effect of crack growth due to stress corrosion cracking (SCC) in determining the ESCs is also discussed. The impact of the revised ESCs by performing two sample fatigue flaw tolerance problems and the associated results are also presented and discussed in this paper.

Micromechanics of Osteonal Cortical Bone Fracture

1998 ◽  
Vol 120 (1) ◽  
pp. 112-117 ◽  
Author(s):  
X. E. Guo ◽  
L. C. Liang ◽  
S. A. Goldstein
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Cement Line ◽  
Linear Elastic ◽  
Age Related ◽  
Microcrack Propagation

Microcracks have been associated with age-related bone tissue fragility and fractures. The objective of this study was to develop a simple osteonal cortical bone model and apply linear elastic fracture mechanics theory to understand the micromechanics of the fracture process in osteonal cortical bone and its dependence on material properties. The linear fracture mechanics of our composite model of conical bone, consisting of an osteon and interstitial bone tissue, was characterized in terms of a stress intensity factor (SIF) near the tip of a microcrack. The interaction between a microcrack and an osteon was studied for different types of osteons and various spacing between the crack and the osteon. The results of the analysis indicate that the fracture mechanics of osteonal cortical bone is dominated by the modulus ratio between the osteon and interstitial bone tissue: A soft osteon promotes microcrack propagation toward the osteon (and cement line) while a stiff one repels the microcrack from the osteon (and cement line). These findings suggest that newly formed, low-stiffness osteons may toughen cortical bone tissue by promoting crack propagation toward osteons. A relatively accurate empirical formula also was obtained to provide an easy estimation of the influence of osteons on the stress intensity factor.

Closed Form Expressions for Fracture Mechanics Analysis of Cracked Pipes

1985 ◽  
Vol 107 (2) ◽  
pp. 203-205 ◽  
Author(s):  
A. Zahoor
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Internal Pressure ◽  
Closed Form ◽  
Bending Moment ◽  
Axial Tension ◽  
Mechanics Analysis ◽  
Pipe Radius

Closed form stress intensity factor (K1) expressions are presented for cracks in pipes subjected to a variety of loading conditions. The loadings considered are: 1) axial tension, 2) remotely applied bending moment, and 3) internal pressure. Expressions are presented for circumferential and axial cracks, and include both part-through and through-wall crack geometries. The closed form K1 expressions are valid for pipe radius to wall thickness ratio between 5 and 20.

J-Integral Evaluation for Calculating Structural Intensity and Stress Intensity Factor Using Commercial Finite Element (FE) Solutions

2013 ◽  
Vol 650 ◽  
pp. 379-384 ◽  
Author(s):  
Jong Wan Hu
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Integral Approach ◽  
J Integral ◽  
Fe Modeling ◽  
Linear Elastic ◽  
Structural Intensity

This report is mainly performed to investigate finite element (FE) modeling and post-processing capacities for fracture mechanics analyses characterized by the stress intensity factor (SIF) at successively stationary crack tip positions. As part of a linear elastic fracture mechanics (LEFM) analysis, the determination of stress intensity factor distribution can also be adopted by J-integral approach. The aim of this report is to review three papers related to estimate J-integrals through FE study and represent the theoretical backgrounds. Furthermore, the technical details for both FE modeling and SIF evaluation will be described in this report based on complete understanding of three reference papers. These numerical approaches to deal with SIF evaluation of general cracks can be applied in 2D and 3D FE models.

Assessment of Methods in Girth Welds of Steel Pipelines

2005 ◽  
Vol 473-474 ◽  
pp. 243-248 ◽  
Author(s):  
Gyula Nagy ◽  
János Lukács ◽  
Imre Török
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
The Other ◽  
Burst Test ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Material Discontinuities ◽  
Girth Welds

This paper presents two basic methods for the assessment of failed girth welds of steel hydrocarbon transporting pipelines. One of them is based on the principles of linear elastic fracture mechanics (LEFM) and stress intensity factor conception for planar material discontinuities, and the other can be used for the complex assessment of all kinds of occurring defects. The results of the presented methods are compared to the results of burst test of pipeline sections containing a failed girth weld and cut from a Hungarian gas pipeline.

VALIDITY OF THE DIRECT RELATION BETWEEN THE FRACTURE MECHANICS PARAMETERS, K AND G, IN THE CASE OF BONE

2004 ◽  
Vol 04 (03) ◽  
pp. 321-331 ◽  
Author(s):  
SATYA PRASAD PARUCHURU ◽  
KOGANTI MOHAN RAO ◽  
XIAODU WANG ◽  
C. M. AGRAWAL
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Sampling Site ◽  
Direct Relation ◽  
Linear Elastic

The critical values of stress intensity factor and energy release rate (KIc, GIc) are important fracture mechanics parameters used in the characterization of bone fracture, assessment of bone quality, and prosthesis design. There exists, a direct relationship between stress intensity factor, K and energy release rate, G that holds good for linear elastic, isotropic, and homogeneous materials. As bone is anisotropic and non-homogeneous, whether or not the relationship is still valid is an important factor. Bone is a brittle material and if it is tested for a particular crack orientation and at a particular sampling site, it may behave as a linear elastic, isotropic, and homogeneous material. The present work verifies the direct relation between K and G of bone in the case of tangential cracks.

The Application of Fracture Mechanics in Highway Tunnel Lining Cracking

2014 ◽  
Vol 580-583 ◽  
pp. 1377-1381
Author(s):  
Song Zhou Chen
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Stress Field ◽  
Tunnel Lining ◽  
Concrete Fracture ◽  
Linear Elastic ◽  
Highway Tunnel ◽  
Elastic Fracture

Lining cracks of highway tunnel has a very important effect on the healthy operation of the tunnel. Establishing the model for concrete fracture mechanics evaluation, we could identify the tunnel lining cracking situation. By using Linear elastic fracture mechanics method we could calculate the stress field of crack in the lining. Separately by different depth we have calculated crack stress intensity factor. We get that growing rates of variation of stress intensity factor as the crack depths increase. So lining tunnel health operations severely cracked.

The Crack Limit Analysis Based on the Fracture Mechanics of the Main Arch of the Stone Arch Bridge

2013 ◽  
Vol 361-363 ◽  
pp. 1155-1159
Author(s):  
Le Fei Zhang ◽  
Zi Lin Yi ◽  
Yong Jun Deng
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Limit Analysis ◽  
Crack Width ◽  
Limit Problem ◽  
Arch Bridge ◽  
The Impact ◽  
Main Arch

This paper is based on fracture mechanics to calculate the arch bridge crack spacing circle and the stress intensity factor. Then the relation between the cracks spacing limit problem is calculated. And stress intensity factor relations under the same crack length and the same pull force is discussed. Finally the analysis shows that the height of the fracture cracks into the crack width as the impact factor is feasible.

Study on the Relationship Between Interaction Factors and Stress Intensity Factor for Elliptical Flaws

2017 ◽  
Author(s):  
Kisaburo Azuma ◽  
Yinsheng Li ◽  
Kunio Hasegawa
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Front ◽  
Elastic Solid ◽  
Element Analysis ◽  
Linear Elastic ◽  
Close Proximity ◽  
Interaction Factors ◽  
The Relationship

The interaction of multiple flaws in close proximity to one another may increase the stress intensity factor of the flaw in structures and components. This interaction effect is not distributed uniformly along the crack front. For instance, the strongest interaction is generally observed at the point closest to a neighboring flaw. For this reason, the closest point could show a higher value of the stress intensity factor than all other points in some cases, even if the original value at the point of the single flaw is relatively low. To clarify the condition when the closest point shows the maximum stress intensity factor, we investigated the interaction of two similar elliptical flaws in an infinite model subjected to remote tension loading. The stress intensity factor of the elliptical flaws was obtained by performing finite element analysis of a linear elastic solid. The results indicated that the interaction factors along the crack front can be expressed by a simple empirical formula. Finally, we show the relationship between geometrical features of the flaw and the stress intensity factor at the closest point to a neighboring flaw.

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