Download or read book Improved Stress intensity Factors for Semi elliptical Surface Cracks in Finite thickness Plates written by I. S. Raju and published by . This book was released on 1977 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Re Evaluation of Finite Element Models and Stress Intensity Factors for Surface Cracks Emanating from Stress Concentrations written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-28 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A re-evaluation of the 3-D finite-element models and methods used to analyze surface crack at stress concentrations is presented. Previous finite-element models used by Raju and Newman for surface and corner cracks at holes were shown to have ill-shaped elements at the intersection of the hole and crack boundaries. These ill-shaped elements tended to make the model too stiff and, hence, gave lower stress-intensity factors near the hole-crack intersection than models without these elements. Improved models, without these ill-shaped elements, were developed for a surface crack at a circular hole and at a semi-circular edge notch. Stress-intensity factors were calculated by both the nodal-force and virtual-crack-closure methods. Both methods and different models gave essentially the same results. Comparisons made between the previously developed stress-intensity factor equations and the results from the improved models agreed well except for configurations with large notch-radii-to-plate-thickness ratios. Stress-intensity factors for a semi-elliptical surface crack located at the center of a semi-circular edge notch in a plate subjected to remote tensile loadings were calculated using the improved models. The ratio of crack depth to crack length ranged form 0.4 to 2; the ratio of crack depth to plate thickness ranged from 0.2 to 0.8; and the ratio of notch radius to the plate thickness ranged from 1 to 3. The models had about 15,000 degrees-of-freedom. Stress-intensity factors were calculated by using the nodal-force method. Tan, P. W. and Raju, I. S. and Shivakumar, K. N. and Newman, J. C., Jr. Langley Research Center RTOP 505-63-01-05...

Download or read book A Comparison of Stress Intensity Factors for Semi elliptical Surface Cracks in Plates of Finite Thickness written by D. J. Portch and published by . This book was released on 1977 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Re evaluation of Finite element Models and Stress intensity Factors for Surface Cracks Emanating from Stress Concentrations written by and published by . This book was released on 1988 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Review and Assessment of the Stress intensity Factors for Surface Cracks written by J. C. Newman (Jr) and published by . This book was released on 1978 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress intensity Factors for Small Surface and Corner Cracks in Plates written by I. S. Raju and published by . This book was released on 1988 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Point Load Weight Functions for Semi Elliptical Cracks in Finite Thickness Plate written by Xin Wang and published by . This book was released on 2012 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the application of the weight function method for the calculation of stress intensity factors for surface semi-elliptical cracks in finite thickness plates subjected to arbitrary two-dimensional stress fields. A new general mathematical form of point load weight function has been formulated by taking advantage of the knowledge of a few specific weight functions for two-dimensional planar cracks available in the literature and certain properties of the weight function in general. The existence of the generalized form of the weight function simplifies the determination of a specific weight function for specific crack configurations. The determination of a specific weight function is reduced to the determination of the parameters of the generalized weight function expression. These unknown parameters can be determined from reference stress intensity factor solutions. This method is used to derive the weight functions for semi-elliptical surface cracks in finite thickness plates. The derived weight functions are then validated against stress intensity factor solutions for several linear and non-linear two-dimensional stress distributions. The derived weight functions are particularly useful for the fatigue crack growth analysis of planar surface cracks subjected to fluctuating nonlinear stress fields resulting from surface treatment (shot peening), stress concentration, or welding (residual stress).

Download or read book Analysis of Surface Cracks in Finite Plates Under Tension Or Bending Loads written by and published by . This book was released on 1979 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress Intensity Factors and Weight Functions written by Theo Fett and published by Computational Mechanics. This book was released on 1997 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book the authors describe methods for the calculation of weight functions. In the first part they discuss the accuracy and convergence behaviour of methods for one- and two-dimensional cracks, while in the second part they provide solutions for cracks subjected to mode-I and mode-II loading.

Download or read book Analyses of Surface Cracks in Finite Plates Under Tension Or Bending Loads written by J. C. Newman and published by . This book was released on 1979 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Three Dimensional Crack Problems written by M.K. Kassir and published by Springer. This book was released on 1975-04-30 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Weight Functions and Stress Intensity Factor Solutions written by Xue-Ren Wu and published by Pergamon. This book was released on 1991 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture mechanics is an indispensible tool in the design and safe operation of damage tolerant structures. One of the essential elements in fracture mechanics based analysis is the stress intensity factor. This book provides a powerful theoretical background to the weight function method in fracture mechanics and numerous stress intensity factors. Part I gives a theoretical background and overview of the weight function method. Part II provides further details of the weight functions for various geometries and a large number of stress intensity factor solutions. Part II deals with the determination of crack opening displacements, Dugdale model solutions and crack opening areas.

Download or read book Stress intensity Factors Along Three dimensional Elliptical Crack Fronts written by M. Gosz and published by . This book was released on 1998 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Stress and Fracture Analyses of Semi Elliptical Surface Cracks written by WG. Reuter and published by . This book was released on 2000 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present paper concentrates on both elastic and elastic-plastic finite-element stress analyses of the surface crack in a plate subjected to tension and bending loads. Stress-intensity factor (K) equations that cover a wider range of crack-length-to-width ratios, than those previously developed by Newman and Raju, for various crack-depth-to-crack-length ratios and crack-depth-to-plate-thickness ratios have been developed and are presented. These equations are used in the subsequent fracture analyses of surface crack specimens subjected to tension and bending loads. From elastic-plastic finite-element analyses, the variations of a hyper-local constraint parameter (?h) along the surface-crack front were studied to identify the region of maximum constraint and the critical fracture location. (The hyper-local constraint parameter is based on the average normal stresses acting over the plastic-zone region on a line in the crack plane perpendicular to the crack front.) The application of linear-elastic fracture mechanics to fracture of surface-crack specimens made of a high-strength D6AC steel are presented for both tension and bending loads. Two methods were used to characterize fracture: the K2-integral around the crack front and K at a critical fracture location (?c). The critical fracture location was the location of the maximum of the product of K times ?h. These two methods were used to evaluate the fracture toughness for both the crack-initiation loads and at the maximum failure load conditions. For tension and bending loads, the K2-integral method correlated 90% of the fracture data within ±25% in terms of load, whereas K at the critical fracture location correlated the data within ±20%.

Download or read book Stress Intensity Factors for Small Surface and Corner Cracks in Plates written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-26 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional finite-element and finite-alternating methods were used to obtain the stress-intensity factors for small surface and corner cracked plates subjected to remote tension and bending loads. The crack-depth-to-crack-length ratios (a/c) ranged from 0.2 to 1 and the crack-depth-to-plate-thickness ratios (a/t) ranged from 0.05 to 0.2. The performance of the finite-element alternating method was studied on these crack configurations. A study of the computational effort involved in the finite-element alternating method showed that several crack configurations could be analyzed with a single rectangular mesh idealization, whereas the conventional finite-element method requires a different mesh for each configuration. The stress-intensity factors obtained with the finite-element-alternating method agreed well (within 5 percent) with those calculated from the finite-element method with singularity elements. Raju, I. S. and Atluri, S. N. and Newman, J. C., Jr. Langley Research Center RTOP 505-63-01-05

Download or read book Stress intensity Factor Equations for Cracks in Three dimensional Finite Bodies Subjected to Tension and Bending Loads written by J. C. Newman and published by . This book was released on 1984 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress Intensity Magnification for Deep Surface Cracks in Sheets and Plates written by Robert B. Anderson and published by . This book was released on 1970 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Irwin stress intensity factor for surface cracks with crack depths less than half the plate thickness is extended to cases of relatively deep cracks by including the effect of the free surface opposite the crack. The stress intensity magnification factor is given as a function of applied load, crack length, crack depth, sheet thickness, yield strength, and Poisson's ratio. The combinations of these variables for which the plastic zone extends completely through the thickness a r e also predicted. The range of applicability of the analysis to surface-crack specimen data was investigated in terms of crack-depth-to-specimen-thickness ratio and crack depth-to-length ratio.