Author: J. C. NewmanPublisher:
ISBN:
Category :
Languages : en
Pages : 98
Book Description
Stress-intensity Factor Equations for Cracks in Three-dimensional Finite Bodies Subjected to Tension and Bending Loads
Author: J. C. NewmanStress Intensity Factors for Three-dimensional Crack Problems
Author: R. S. BainsPublisher:
ISBN:
Category : Fracture mechanics
Languages : en
Pages : 18
Book Description
Three-Dimensional Crack Problems
Author: M.K. KassirPublisher: Springer
ISBN:
Category : Science
Languages : en
Pages : 516
Book Description
Determination of Stress Intensity Factors for Three Dimensional Crack Problems with Differential Stiffness Method
Author: Zhen Ning SongExperimental evaluation of stress concentration and intensity factors
Author: George C. SihPublisher: Springer Science & Business Media
ISBN: 9400983379
Category : Science
Languages : en
Pages : 407
Book Description
Experiments on fracture of materials are made for various purposes. Of primary importance are those through which criteria predicting material failure by deformation and/or fracture are investigated. Since the demands of engineering application always precede the development of theories, there is another kind of experiment where conditions under which a particular material can fail are simulated as closely as possible to the operational situation but in a simplified and standardized form. In this way, many of the parameters corresponding to fracture such as toughness, Charpy values, crack opening distance (COD), etc. are measured. Obviously, a sound knowledge of the physical theories governing material failure is necessary as the quantity of interest can seldom be evaluated in a direct manner. Critical stress intensity factors and critical energy release rates are examples. Standard test of materials should be distinguished from basic experi ments. They are performed to provide routine information on materials responding to certain conditions of loading or environment. The tension test with or without a crack is among one of the most widely used tests. Because they affect the results, with size and shape of the specimen, the rate of loading, temperature and crack configuration are standardized to enable comparison and reproducibility of results. The American Society for Testing Materials (ASTM) provides a great deal of information on recommended procedures and methods of testing. The objective is to standardize specifications for materials and definition of technical terms.
Stress-intensity Factor Equations for Cracks in Three-dimensional Finite Bodies
Author: A Special Crack Tip Element for Three-dimensional Crack Problems
Author: R. JonesPublisher:
ISBN: 9780642900456
Category : Airplanes
Languages : en
Pages : 22
Book Description
This paper develops a finite element method for determining the stress intensity factors along the edge of a crack in an arbitrary three-dimensional body. A special element is placed around the crack front and in each special element the stresses and displacements are derived using the asymptotic nature of the stress and displacement fields near a crack tip. The method is based on the authors' previous technique for evaluating the stress intensity factors in cracked sheets, and coincides with this method in the case of a through crack in a thin sheet. As illustrative examples the problems of a semicircular surface flaw and an internal penny shaped crack are considered. In each case the computed values of the stress intensity factors are in excellent agreement with known analytical results.
Stress-intensity Factors Along Three-dimensional Elliptical Crack Fronts
Author: M. GoszPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 18
Book Description
The objective of the present investigation is to determine the mode I stress-intensity factors along two symmetric surface cracks emanating from a centrally located hole in a rectangular plate (the so-called Round Robin Problem) using the domain integral method. In order to validate the present three-dimensional domain integral implementation, two comparisons were made with benchmark solutions. We first considered the problem of an elliptical crack embedded in a rectangular plate. For plate dimensions much greater than the largest characteristic dimension of the elliptical crack, we compared the present finite element results with the solution of Irwin (1962) for an elliptical crack embedded in an infinitely extended solid. Next, we considered the problem of a quarter-elliptical comer crack in a rectangular, plate and compared the results with those of Newman and Raju (1983). Excellent agreement was obtained for both benchmark comparisons.
Plates and shells with cracks
Author: George C. SihPublisher: Springer Science & Business Media
ISBN: 940101292X
Category : Science
Languages : en
Pages : 344
Book Description
This third volume of a series on Mechanies of Fraeture deals with eraeks in plates and shelIs. It was noted in Volume 2 on three-dimensional eraek problems that additional free surfaees can lead to substantial mathematical complexities, often making the analysis unmanageable. The theory of plates and shelIs forms a part of the theory of elasticity in which eertain physieal assumptions are made on the basis that the distanee between two bounded surfaees, either fiat or eurved, is small in eomparison with the overall dimen sions of the body. In modern times, the broad and frequent applieations of plate- and shell-like struetural members have aeted as a stimulus to whieh engineers and researchers in the field of fracture meehanies have responded with a wide variety of solutions of teehnieal importanee. These eontributions are covered in this book so that the reader may gain an understanding of how analytieal treat me nt s ofplates and shells containing initial imperfeetions in the form of eraeks are earried out. The development of plate and shell theories has involved long standing controversy on the eonsisteney of omitting eertain small terms and at the same time retaining others of the same order of magnitude. This defieieney depends on the ratio of the plate or shell thiekness, h, to other eharaeteristie dimensions and eannot be eompletely resolved in view of the approximations inherent in the transverse dependence of the extensional and bending stresses.
Stress Intensity Factor Determination for Three-Dimensional Crack Using the Displacement Discontinuity Method with Applications to Hydraulic Fracture Height Growth and Non- Planar Propagation Paths
Author: Farrokh SheibaniPublisher:
ISBN:
Category : Technology
Languages : en
Pages :
Book Description
Stress intensity factor determination plays a central role in linearly elastic fracture mechanics (LEFM) problems. Fracture propagation is controlled by the stress field near the crack tip. Because this stress field is asymptotic dominant or singular, it is characterized by the stress intensity factor (SIF). Since many rock types show brittle elastic behaviour under hydrocarbon reservoir conditions, LEFM can be satisfactorily used for studying hydraulic fracture development. The purpose of this paper is to describe a numerical method to evaluate the stress intensity factor in Mode I, II and III at the tip of an arbitrarily-shaped, embedded cracks. The stress intensity factor is evaluated directly based on displacement discontinuities (DD) using a three-dimensional displacement discontinuity, boundary element method based on the equations of proposed in [1]. The boundary element formulation incorporates the fundamental closed-form analytical solution to a rectangular discontinuity in a homogenous, isotropic and linearly elastic half space. The accuracy of the stress intensity factor calculation is satisfactorily examined for rectangular, penny-shaped and elliptical planar cracks. Accurate and fast evaluation of the stress intensity factor for planar cracks shows the proposed procedure is robust for SIF calculation and crack propagation purposes. The empirical constant proposed by [2] relating crack tip element displacement discontinuity and SIF values provides surprisingly accurate results for planar cracks with limited numbers of constant DD elements. Using the described numerical model, we study how fracturing from misaligned horizontal wellbores might results in non-uniform height growth of the hydraulic fracture by evaluating of SIF distribution along the upper front of the fracture.