Author: I. S. RajuPublisher:
ISBN:
Category :
Languages : en
Pages : 52
Book Description
Improved Stress-intensity Factors for Semi-elliptical Surface Cracks in Finite-thickness Plates
Author: I. S. RajuA Re-Evaluation of Finite-Element Models and Stress-Intensity Factors for Surface Cracks Emanating from Stress Concentrations
Author: National Aeronautics and Space Adm NasaPublisher:
ISBN: 9781729062067
Category :
Languages : en
Pages : 36
Book Description
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...
A Comparison of Stress Intensity Factors for Semi-elliptical Surface Cracks in Plates of Finite Thickness
Author: D. J. PortchA Re-evaluation of Finite-element Models and Stress-intensity Factors for Surface Cracks Emanating from Stress Concentrations
Author: A Review and Assessment of the Stress-intensity Factors for Surface Cracks
Author: J. C. Newman (Jr)Stress-intensity Factors for Small Surface and Corner Cracks in Plates
Author: I. S. RajuWeight Functions and Stress Intensity Factor Solutions
Author: Xue-Ren WuPublisher: Pergamon
ISBN:
Category : Science
Languages : en
Pages : 540
Book Description
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.
Point Load Weight Functions for Semi-Elliptical Cracks in Finite Thickness Plate
Author: Xin WangPublisher:
ISBN:
Category : Basal metabolism
Languages : en
Pages : 19
Book Description
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).
Analysis of Surface Cracks in Finite Plates Under Tension Or Bending Loads
Author: Analyses of Surface Cracks in Finite Plates Under Tension Or Bending Loads
Author: J. C. NewmanPublisher:
ISBN:
Category : Materials
Languages : en
Pages : 52
Book Description