Part-Elliptical Cracks Emanating From Open and Loaded Holes in Plates

1979 ◽  
Vol 101 (1) ◽  
pp. 12-17 ◽  
Author(s):  
T. E. Kullgren ◽  
F. W. Smith
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Crack Opening ◽  
Plate Thickness ◽  
Hole Diameter ◽  
Elastic Analysis ◽  
Intensity Factors ◽  
Linear Elastic ◽  
Elliptical Cracks

A linear elastic analysis using the finite element-alternating method is conducted for problems of single semi-elliptical and double quarter-elliptical cracks near fastener holes. Mode-one stress intensity factors are presented along the crack periphery for cases of open and loaded holes and crack opening displacements are calculated. Results are shown for a variety of crack geometries and loading conditions and for two ratios of hole diameter to plate thickness.

Quarter Elliptical Cracks Emanating From Holes in Plates

1978 ◽  
Vol 100 (2) ◽  
pp. 144-149 ◽  
Author(s):  
T. E. Kullgren ◽  
F. W. Smith ◽  
G. P. Ganong
Keyword(s):  
Finite Element ◽  
Analytic Solution ◽  
Plate Thickness ◽  
Hole Diameter ◽  
Solution Technique ◽  
Element Solution ◽  
Intensity Factors ◽  
Flat Plates ◽  
Linear Elastic ◽  
Elliptical Cracks

The finite element-alternating method, a linear elastic solution technique, is refined and applied to problems of quarter-elliptical cracks in irregular bodies. The method involves the iterative superposition of a finite element solution for stresses in an unflawed body and an analytic solution for stresses in an infinite solid containing a flat elliptical crack. Mode-one stress intensity factors are presented along the periphery of quarter-elliptical cracks emanating from open fastener holes in flat plates. Results are shown for a variety of crack geometries and two hole-diameter to plate-thickness ratios. Comparisons are made with experimental results of other authors.

Update: Application of the Finite Element Method to Linear Elastic Fracture Mechanics

2010 ◽  
Vol 63 (2) ◽  
Author(s):  
Leslie Banks-Sills
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Linear Elastic Fracture Mechanics ◽  
The Finite Element Method ◽  
Intensity Factors ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Element Method

Since the previous paper was written (Banks-Sills, 1991, “Application of the Finite Element Method to Linear Elastic Fracture Mechanics,” Appl. Mech. Rev., 44, pp. 447–461), much progress has been made in applying the finite element method to linear elastic fracture mechanics. In this paper, the problem of calculating stress intensity factors in two- and three-dimensional mixed mode problems will be considered for isotropic and anisotropic materials. The square-root singular stresses in the neighborhood of the crack tip will be modeled by quarter-point, square and collapsed, triangular elements for two-dimensional problems, respectively, and by brick and collapsed, prismatic elements in three dimensions. The stress intensity factors are obtained by means of the interaction energy or M-integral. Displacement extrapolation is employed as a check on the results. In addition, the problem of interface cracks between homogeneous, isotropic, and anisotropic materials is presented. The purpose of this paper is to present an accurate and efficient method for calculating stress intensity factors for mixed mode deformation. The equations presented here should aid workers in this field to carry out similar analyses, as well as to check their calculations with respect to the examples described.

Computations of Stress Intensity Factors for Deep Cracks in Plates by Using the Tetrahedral Finite Element

2012 ◽  
Author(s):  
Hiroshi Okada ◽  
Hirohito Koya ◽  
Hiroshi Kawai ◽  
Yinsheng Li
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Structural Integrity ◽  
Intensity Factors ◽  
Welded Structures ◽  
Elliptical Cracks

In this paper, stress intensity factor solutions for deep half-elliptical cracks that are applicable to the structural integrity evaluations of welded structures are presented. Welded structures generally have some weld residual stresses resulting in stress corrosion crackings (SCCs). This paper describes a simple way to compute the stress intensity factors under the weld-residual stresses and the mode I stress intensity factor solutions for deep half-elliptical cracks. The residual stresses are set to vary proportional to the constant, the linear, the quadratic and the cubic functions of x which is the distance from the plate surface. Although we use a straightforward finite element method to perform the computations, we can quickly generate the stress intensity factor solutions as we make use of automatic mesh generation program for the tetrahedral finite element. Thus, it is very tractable to generate the finite element models with cracks. Furthermore, present solutions can be compared with those of Li et al. which are also presented in PVP 2012. We conclude that present method is useful for the evaluations of SIFs of cracks under the residual stresses.

Crack Opening Area Solutions for Through-Wall Cracks in the Vicinity of Welded Attachments

2009 ◽  
Author(s):  
J. K. Sharples ◽  
R. Charles ◽  
C. J. Madew ◽  
P. J. Budden
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Geometry ◽  
Crack Opening ◽  
Stress Profile ◽  
Intensity Factors ◽  
Finite Element Study ◽  
Plate Geometry ◽  
Element Study

This paper presents the latest results of a finite element study undertaken to evaluate crack opening areas (COA) and stress intensity factors (KI) for through-wall cracks located in the region where an attachment is welded to a plate geometry. Both membrane and bend loads have been considered. In addition, COAs and stress intensity factors have been evaluated for the same crack sizes located in a simple plate geometry. These values have been determined by applying both membrane and bend stresses to the plain plate, the magnitudes of which correspond to those for the stress profile in the un-cracked complex geometry in the vicinity of where the cracks would be introduced. This has enabled information to be established on the conservatism or otherwise of using simple plate solutions to evaluate COAs and stress intensity factors for cracks in the complex geometry.

Crack Opening Area Solutions for Through-Wall Cracks in a Complex Geometry

2008 ◽  
Author(s):  
R. Charles ◽  
J. K. Sharples ◽  
P. J. Budden
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Geometry ◽  
Crack Opening ◽  
Complex Geometries ◽  
Intensity Factors ◽  
3D Finite Element ◽  
Plate Geometry ◽  
Element Study

This paper presents the results of a finite element study that has been undertaken to evaluate crack opening areas (COA) for through-wall flaws located in the region where an attachment is “welded” to a plate geometry. This represents the first stage of a study to evaluate crack opening area solutions for flaws situated in complex geometries such as pipe elbows, nozzles and other attachments. The work has been performed by way of 3D finite element methods. In addition to COA evaluations, stress intensity factors have been determined in the study. The crack opening areas and stress intensity factors evaluated for this complex geometry have been compared with those for the same flaw sizes located in a simple plate geometry. This has led to an initial understanding of how conservative or otherwise the use of plate solutions is for representing the more complex geometry cases.

Sign in / Sign up

Export Citation Format

Share Document