The Enriched Element for Finite Element Analysis of Three-Dimensional Elastic Crack Problems

1980 ◽  
Vol 102 (4) ◽  
pp. 347-352 ◽  
Author(s):  
P. D. Hilton ◽  
B. V. Kiefer
Keyword(s):  
Finite Element ◽  
Free Surface ◽  
Stress Intensity ◽  
Crack Front ◽  
Three Dimensional ◽  
Crack Edge ◽  
Element Analysis ◽  
Front Solution ◽  
Penny Shaped Crack ◽  
Crack Problems

An improved procedure for enriching three-dimensional isoparametric elements with the asymptotic crack front solution is described. Results from finite element calculations, involving these enriched elements, for the three-dimensional problems of a straight crack in plane strain and an axisymmetric penny-shaped crack which demonstrate the high degree of accuracy attainable are presented. Some finite-element solutions for through-crack and surface flaw problems are then reported showing the influence of a free surface on the variation of the stress intensity along the crack edge. Special treatments of the crack front-free surface stress intensity are implemented and the results discussed.

Three-Dimensional Finite Element Analysis of Elastic-Plastic Crack Problems

1981 ◽  
Vol 103 (3) ◽  
pp. 214-218 ◽  
Author(s):  
B. V. Kiefer ◽  
P. D. Hilton
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
Crack Front ◽  
Stress Component ◽  
Three Dimensional ◽  
Specimen Thickness ◽  
Element Analysis ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Crack Problems

A three-dimensional, elastic-plastic finite element program is developed and applied to analyze the stress field in a plate containing a through crack. The center cracked plate is subjected to uniform tensile loading which results in mode I opening of the crack surfaces. Transverse variations of the opening tensile stress component and of the effective stress (von Mises) in the vicinity of the crack front are presented. They clearly demonstrate the three-dimensional nature of this problem with distributions that depend on specimen thickness. For thinner plates, the plastic deformation concentrates near the plate surfaces while the normal stress is largest in the plate interior. In thicker plates the deformation and normal stress fields are more uniform in the plate interior near the crack front, but they develop a rapid boundary layer-type variation in the vicinity of the plate surfaces.

Finite Element Analysis of Load Capacity on Coupling Clamps for Pipe

2012 ◽  
Vol 201-202 ◽  
pp. 741-744 ◽  
Author(s):  
Zhen Ning Hou ◽  
Jun Wu ◽  
Qing Wang ◽  
Hong Gen Tian ◽  
Nan Chao ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Optimization Design ◽  
Load Capacity ◽  
Three Dimensional ◽  
Process Conditions ◽  
Fe Model ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Element Approach

A finite element approach based on Ansys is developed to simulate stress intensity distribution in a three dimensional model of coupling clamp joint, which includes ferrules, pipe caps and bolts. The characteristics of stress intensity distributions of coupling clamp joint under strength pressure loading have been studied by means of the non-linear finite element method. The FE model can also predict the clamp quality and tolerances to be expected under different process conditions and define the most effective process parameters to influence the tolerances. The study could give us a better understanding on the mechanism and basis for optimization design of the coupling clamp joint.

Development of the Next-Generation Computational Fracture Mechanics Simulator on the Earth Simulator 2

2012 ◽  
Author(s):  
Kaworu Yodo ◽  
Hiroshi Kawai ◽  
Hiroshi Okada ◽  
Masao Ogino ◽  
Ryuji Shioya
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Large Scale ◽  
Three Dimensional ◽  
Intensity Factors ◽  
Element Analysis ◽  
Mechanics Analysis ◽  
Analysis System

Fracture mechanics analysis using the finite element method has been one of the key methodologies to evaluate structural integrity for aging infrastructures such as aircraft, ship, power plants, etc. However, three-dimensional crack analyses for structures with highly complex three-dimensional shapes have not widely been used, because of many technical difficulties such as the lack of enough computational power. The authors have been developing a fracture mechanics analysis system that can deal with arbitrary shaped cracks in three-dimensional structures. The system consists of mesh generation software, a finite element analysis program and a fracture mechanics module. In our system, a Virtual Crack Closure-Integral Method (VCCM) for the quadratic tetrahedral finite elements is adopted to evaluate the stress intensity factors. This system can perform the three-dimensional fracture analyses. Fatigue and SCC crack propagation analyses with more than one cracks of arbitrary complicated shapes and orientations. The rate and direction of crack propagation are predicted by using appropriate formulae based on the stress intensity factors. When the fracture mechanics analysis system is applied to the complex shaped aging structures with the cracks which are modeled explicitly, the size of finite element analysis tends to be very large. Therefore, a large scale parallel structural analysis code is required. We also have been developing an open-source CAE system, ADVENTURE. It is based on the hierarchical domain decomposition method (HDDM) with the balancing domain decomposition (BDD) pre-conditioner. A general-purpose parallel structural analysis solver, ADVENTURE_Solid is one of the solver modules of the ADVENTURE system. In this paper, we combined VCCM for the tetrahedral finite element with ADVENTURE system and large-scale fracture analyses are fully automated. They are performed using the massively parallel super computer ES2 (Earth Simulator 2) which is owned and run by JAMSTEC (Japan Agency for Marine-Earth Science and Technology).

Stress Intensity Factor of an Elliptical Crack With a Wavy Crack Front

2016 ◽  
Author(s):  
Masayuki Arai
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Front ◽  
Perturbation Technique ◽  
Three Dimensional ◽  
Elastic Field ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, the stress intensity factor KI for the crack front line a − ε(1 + cosmθ), which is slightly perturbed from a complete circular line with a radius of a, is determined. The method used in this study is based upon the perturbation technique developed by Rice for solving the elastic field of a crack whose front slightly deviates from some reference geometry. It is finally shown that the solution for the stress intensity factor matches the results of a three-dimensional finite element analysis.

Numerical Analysis of Fracture Parameters of Multiple Interacting Cracks

2009 ◽  
Vol 417-418 ◽  
pp. 277-280
Author(s):  
Yong Jie Liu ◽  
Qing Yuan Wang ◽  
Xiang Guo Zeng ◽  
Da Li Lv
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Main Crack ◽  
The Finite Element Method ◽  
Intensity Factors ◽  
Element Analysis ◽  
Fracture Parameters ◽  
Crack Problems

Multiple interacting crack problems for 3-point bending specimen were studied in this article. Two symmetrical minor cracks were placed in the structure, besides a main crack at the middle, and using the finite element method program ABAQUS, the energy release rate (G) and the stress intensity factor (SIF) were evaluated based on the virtual crack closure technology（VCCT）in conjunction with finite element analysis(FEA). Then, effects of variation in relative lengths and locations of the minor cracks on the stress intensity factors of the main crack were obtained and analyzed. Finally, the approach was applied to dynamic analysis, and influences of interacting effects among the cracks on dynamic fracture parameters were also studied.

scholarly journals A semi-analytical method to evaluate the J-R curve for the surface-cracked round bar under three-point bending

2021 ◽  
Author(s):  
Guangwei He ◽  
Lixun CAI ◽  
Chen Bao ◽  
Xudong Qian
Keyword(s):  
Finite Element ◽  
Crack Front ◽  
Analytical Method ◽  
Three Dimensional ◽  
Element Analysis ◽  
Round Bar ◽  
Dimensional Finite Element ◽  
Load Displacement ◽  
Three Dimensional Finite Element ◽  
Analytical Expressions

The current paper presents a semi-analytical method for obtaining J-R curves of round bars with elliptical cracks. This method derives the semi-analytical expressions between load and displacement, J-integral and displacement for surface-cracked round bars, based on the energy density equivalence principle, taking into account the effect of material and crack size. The validity of semi-analytical expressions examined by three-dimensional finite element analysis shows that load~displacement curves and J-integral~load curves predicted by the expressions match well with the simulation results. Through fracture toughness testing conducted on the carbon steel 45, the load~displacement data are used to calculate the average J-R curves for the surface-cracked round bar by the semi-analytical expressions. With the distributions of J-integral along the crack front obtained from three-dimensional finite element analyses, this study also determines the J-R curves at different crack-front points.

Finite element analysis of cracked and uncracked tubular T-joint

1986 ◽  
Vol 13 (3) ◽  
pp. 261-269 ◽  
Author(s):  
G. S. Bhuyan ◽  
M. Arockiasamy ◽  
K. Munaswamy ◽  
O. Vosikovsky
Keyword(s):  
Finite Element ◽  
Crack Front ◽  
Three Dimensional ◽  
Singular Element ◽  
Singular Stress ◽  
Element Analysis ◽  
Joint Stress ◽  
Weld Toe ◽  
Singular Stress Field ◽  
Bending Loads

A welded tubular T-joint is analysed using finite element methods to obtain through-thickness and surface stresses due to axial and in-plane bending loads. The effects of a shallow weld toe crack on the stress redistribution are studied. The two-dimensional analysis of the joint includes the membrane stiffness representation by plane stress element and the flexural stiffness by plate bending element. For the three-dimensional analyses, the joint is modelled using incompatible solid elements to improve flexural characteristics. The embedded elliptical crack front is modelled by straight-line segments. The region at the vicinity of the crack is discretized using special elements, which produce a singular stress field at the crack front. Key words: tubular joint, stress analysis, weld toe crack, incompatible element, singular element.

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