Download or read book Three Dimensional Elastic Surface Cracks written by TA. Cruse and published by . This book was released on 1988 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses a variety of issues associated with the elastic fracture mechanics modeling of surface cracks; both analytical and experimental issues are addressed. The primary analytical focus is on the use of the boundary integral equation method for elastic fracture mechanics analysis. An advanced code is highlighted. A new formulation for three-dimensional crack-surface integral equations is presented with some new analytical results associated with the free-surface singularity. Essential agreements with the results of Benthem are obtained. Fatigue crack growth results for surface cracks in tension and bending are compared with analytical solutions. It is shown that surface cracks in tension grow essentially in accord with an elastic fracture mechanics prediction, whereas surface cracks in bending do not conform to the elastic prediction, based on surface values of the elastic stress-intensity factor. Some thoughts for further research are given.

Download or read book Three Dimensional Elastic Plastic Analysis of Small Circumferential Surface Cracks in Pipes Subjected to Bending Load written by C. Franco and published by . This book was released on 1992 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study presents the elastic-plastic behavior of a circumferentially surfacecracked pipe using the finite element method based on a three-dimensional model.

Download or read book Three dimensional Elastic Stress and Displacement Analysis of Finite Circular Geometry Solids Containing Cracks written by John P. Gyekenyesi and published by . This book was released on 1973 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: A seminumerical method is presented for solving a set of coupled partial differential equations subject to mixed and coupled boundary conditions. The use of this method is illustrated by obtaining solutions for two circular geometry and mixed boundary value problems in three-dimensional elasticity. Stress and displacement distributions are calculated in an axisymmetric, circular bar of finite dimensions containing a penny-shaped crack. Approximate results for an annular plate containing internal surface cracks are also presented.

Download or read book Three dimensional Elastic plastic Finite element Analyses of Constraint Variations in Cracked Bodies written by and published by . This book was released on 1993 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Three dimensional Elastic plastic Analysis of Shallow Cracks in Single edge crack tension Specimens written by and published by . This book was released on 1990 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fracture Mechanics Nineteenth Symposium written by Thomas A. Cruse and published by ASTM International. This book was released on 1988 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Elastic Plastic J Integral Solutions Or Surface Cracks in Tension Using an Interpolation Methodology written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2019-01-15 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: No closed form solutions exist for the elastic-plastic J-integral for surface cracks due to the nonlinear, three-dimensional nature of the problem. Traditionally, each surface crack must be analyzed with a unique and time-consuming nonlinear finite element analysis. To overcome this shortcoming, the authors have developed and analyzed an array of 600 3D nonlinear finite element models for surface cracks in flat plates under tension loading. The solution space covers a wide range of crack shapes and depths (shape: 0.2 less than or equal to a/c less than or equal to 1, depth: 0.2 less than or equal to a/B less than or equal to 0.8) and material flow properties (elastic modulus-to-yield ratio: 100 less than or equal to E/ys less than or equal to 1,000, and hardening: 3 less than or equal to n less than or equal to 20). The authors have developed a methodology for interpolating between the goemetric and material property variables that allows the user to reliably evaluate the full elastic-plastic J-integral and force versus crack mouth opening displacement solution; thus, a solution can be obtained very rapidly by users without elastic-plastic fracture mechanics modeling experience. Complete solutions for the 600 models and 25 additional benchmark models are provided in tabular format. Allen, P. A. and Wells, D. N. Marshall Space Flight Center NASA/TP-2013-217480, M-1356

Download or read book Stress intensity Factor Equations for Cracks in Three dimensional Finite Bodies written by and published by . This book was released on 1981 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Quantification of the Constraint Effect Along a Three Dimensional Crack Front written by Xin Wang and published by . This book was released on 2008 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we examined the characterization of constraint effects for surface cracked plates under uniaxial and biaxial tension loadings. First, three-dimensional (3D) modified boundary layer analyses were conducted using the finite element method to study the constraint effect at a typical 3D crack front. The analyses were carried out using small geometry change formulation and deformation plasticity material model. Elastic-plastic crack front stress fields at a constant J and various T-stress levels were obtained. Three-dimensional elastic-plastic analyses were performed for semi-circular surface cracks in a finite thickness plate, under remote uniaxial and biaxial tension loading conditions. In topological planes perpendicular to the crack fronts, the crack stress fields were obtained. Then, J-Q and J-T two-parameter approaches are used in characterizing the elastic-plastic crack-tip stress fields along the 3D crack front. It is found that the J-Q characterization provides good estimate for the constraint effect for crack-tip stress fields. Reasonable agreements are achieved between the T-stress based Q-factors and the Q-factors obtained from finite element analysis.

Download or read book Surface crack Growth written by Walter G. Reuter and published by ASTM International. This book was released on 1990 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the symposium (on title) held in Sparks, Nevada, April 1988. Twenty-two peer-reviewed papers are divided into sections on models and experiments (monotonic loading), and fatigue crack growth. Areas addressed include the differences in constraint for 2-D through-thickness cracks and 3-D surface

Download or read book On Wave Propagation in Elastic Solids with Cracks written by Ch Zhang and published by Computational Mechanics. This book was released on 1998 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Begins with both a non-hypersingular time-domain traction boundary integral equation formulation for transient elastodynamic crack analysis and a time-stepping scheme for solving the boundary integral equations. The scheme is applied to analyze three-dimensional rectangular and penny-shaped cracks, and to investigate pulse shape effects on the dynamic stress intensity factor. The corresponding frequency-domain boundary integral equation is given, and time- harmonic wave propagation in randomly cracked solids is treated. The second half of the book deals with the elastodynamic analysis of a periodic array of cracks in plane strain and of anti-plane interface cracks between two different materials, and the effect of the material anistrophy on the near-tip quantities, the scattered far-field, and wave attenuation and dispersion. No index. Annotation copyrighted by Book News, Inc., Portland, OR

Download or read book Elastic Plastic Fracture Mechanics Methodology for Surface Cracks written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Elastic Plastic Fracture Mechanics Methodology has evolved significantly in the last several years. Nevertheless, some of these concepts need to be extended further before the whole methodology can be safely applied to structural parts. Specifically, there is a need to include the effect of constraint in the characterization of material resistance to crack growth and also to extend these methods to the case of 3D defects. As a consequence, this project was started as a 36 month research program with the general objective of developing an elastic plastic fracture mechanics methodology to assess the structural reliability of pressure vessels and other parts of interest to NASA which may contain flaws. The project is divided into three tasks that deal with (1) constraint and thickness effects, (2) three-dimensional cracks, and (3) the Leak-Before-Burst (LBB) criterion. This report period (March 1994 to August 1994) is a continuation of attempts to characterize three dimensional aspects of fracture present in 'two dimensional' or planar configuration specimens (Chapter Two), especially, the determination of, and use of, crack face separation data. Also, included, are a variety of fracture resistance testing results (J(m)R-curve format) and a discussion regarding two materials of NASA interest (6061-T651 Aluminum alloy and 1N718-STA1 nickel-base super alloy) involving a bases for like constraint in terms of ligament dimensions, and their comparison to the resulting J(m)R-curves (Chapter Two). Ernst, Hugo A. and Lambert, D. M. Unspecified Center...

Download or read book Three Dimensional Analysis of Surface Crack Hertzian Stress Field Interaction written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results are presented of a stress intensity factor analysis of semicircular surface cracks in the inner raceway of an engine bearing. The loading consists of a moving spherical Hertzian contact load and an axial stress due to rotation and shrink fit. A 3-D linear elastic Boundary Element Method code was developed to perform the stress analysis. The element library includes linear and quadratic isoparametric surface elements. Singular quarter point elements were employed to capture the square root displacement variation and the inverse square root stress singularity along the crack front. The program also possesses the capability to separate the whole domain into two subregions. This procedure enables one to solve nonsymmetric fracture mechanics problems without having to separate the crack surfaces a priori. A wide range of configuration parameters was investigated. The ratio of crack depth to bearing thickness was varied from one-sixtieth to one-fifth for several different locations of the Hertzian load. The stress intensity factors for several crack inclinations were also investigated. The results demonstrate the efficiency and accuracy of the Boundary Element Method. Moreover, the results can provide the basis for crack growth calculations and fatigue life prediction. Ballarini, R. and Hsu, Y. Unspecified Center BEARINGS; BOUNDARY ELEMENT METHOD; STRESS DISTRIBUTION; STRESS INTENSITY FACTORS; SURFACE CRACKS; AXIAL STRESS; COMPUTER PROGRAMS; CONTACT LOADS; CRACK PROPAGATION; FATIGUE LIFE; FRACTURE MECHANICS; LOAD TESTS...

Download or read book Fracture Mechanics written by Satya N. Atluri and published by ASTM International. This book was released on 1992 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Papers of the June 1990 meeting held in Atlanta, Ga. The first volume (47 papers) concentrates on experimental and theoretical aspects of fracture mechanics. Volume two (26 papers) covers numerical and computational approaches. Topics include: ductile fracture, high-temperature and time-dependent fr

Download or read book Numerical Assessments of Cracks in Elastic Plastic Materials written by Huang Yuan and published by Springer Science & Business Media. This book was released on 2002-04-26 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book a systematic discussion of crack problems in elastic-plastic materials is presented. The state of the art in fracture mechanics research and assessment of cracks is documented, with the help of analytic, asymptotic methods as well as finite element computations. After a brief introduction to fracture mechanics, the two-parameter concept for stationary cracks is studied in addition to the issues in three-dimensional crack fields under coupling with strong out-of-plane effects. Cracks along interfaces and crack growth problems under mixed mode conditions are also treated. A systematic study of stress singularities for different notches is accompanied by detailed finite element computations.

Download or read book On the Variation in Crack Opening Stresses at Different Locations in a Three Dimensional Body written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-09 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crack propagation and closure behavior of thin, and thick middle crack tension specimens under constant amplitude loading were investigated using a three dimensional elastic plastic finite element analysis of fatigue crack propagation and closure. In the thin specimens the crack front closed first on the exterior (free) surface and closed last in the interior during the unloading portion of cyclic loading; a load reduced displacement technique was used to determine crack opening stresses at specified locations in the plate from the displacements calculated after the seven cycle. All the locations were on the plate external surface and were located near the crack tip, behind the crack tip, at the centerline of the crack. With this technique, the opening stresses at the specified points were found to be 0.52, 0.42, and 0.39 times the maximum applied stress. Chermahini, R. G. and Blom, Anders F. Unspecified Center NAG1-529...

Download or read book Three dimensional Elastic Stress and Displacement Analysis of Finite Circular Geometry Solids Containing Cracks written by John P. Gyekenyesi and published by . This book was released on 1973 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: A seminumerical method is presented for solving a set of coupled partial differential equations subject to mixed and coupled boundary conditions. The use of this method is illustrated by obtaining solutions for two circular geometry and mixed boundary value problems in three-dimensional elasticity. Stress and displacement distributions are calculated in an axisymmetric, circular bar of finite dimensions containing a penny-shaped crack. Approximate results for an annular plate containing internal surface cracks are also presented.