Three-dimensional Elastic-plastic Finite-element Analysis of Fatigue Crack Propagation PDF Download

Author: R. G. Chermahini
Publisher:
ISBN:
Category : Airframes
Languages : en
Pages :

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Author: Rahmatollah Ghadimi Chermahini
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 147

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Author: Stephen G. Cupschalk
Publisher:
ISBN:
Category : Stress corresion
Languages : en
Pages : 64

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 48

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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722458737
Category :
Languages : en
Pages : 34

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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...

Author: Corneliu Manu
Publisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 500

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Elastic-plastic finite element analyses were performed to predict the crack opening level profiles in semi-elliptical surface cracks. A script was written to use the commercial finite element code ANSYS to predict opening levels in cracked geometries. The functionality of the scripts was verified by comparing predicted opening levels in two and three-dimensional center-cracked geometries to experimental results. In addition, a parameter study was performed in which various aspects of the modeling routine were modified. This included a mesh refinement study as well as a study into the effect of a strain hardening material. The main focus of the current research, however, is to compare finite element predicted opening levels with published opening levels determined experimentally. Due to the complexities and long run-times involved with these models, no attempt was made at growing the cracks from initial length to final length. Instead, discrete crack lengths at which experimental opening levels were published were instead used. Also, no attempt was made to predict the crack aspect ratio evolution. The finite element predicted opening levels were in all cases significantly lower than those reported experimentally, however, similar trends in both crack opening level profile along the crack front, and opening level variations with crack growth were shown.

Author: R. G. Chermahini
Publisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 296

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Author: Satya N. Atluri
Publisher:
ISBN:
Category :
Languages : en
Pages : 46

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This is a summary of research performed in the areas: (a) development of two-dimensional hybrid finite element procedures to calculate stress intensity factors corresponding to general r to the minus alpha stress singularities in isotropic as well as anistropic materials; (b) study of the convergence of the assumed displacement hybrid finite element procedure in fracture mechanics problems; (c) development of a three-dimensional hybrid finite element procedure to calculate the elastic combined mode stress-intensity factors K1, K2 and K3 that vary along an arbitrarily curved three-dimensional crack front; (d) hybrid finite element solutions of fundamental three-dimensional crack problems; (e) development of a two-dimensional finite element procedure for analyzing plane problems of fracture involving large-scale yielding conditions and under cyclic loading; (f) study of the J-integral as a ductile fracture initiation condition; (g) studies of finite deformation effects near the crack-tip; (h) analysis of stable crack growth under rising load and study of criteria for loss of stability of growth in ductile materials; and (i) elastic-plastic analysis of effects of crack closure on fatigue crack growth rates. (Author).

Author: Sylvie Pommier
Publisher: John Wiley & Sons
ISBN: 1118622693
Category : Technology & Engineering
Languages : en
Pages : 271

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Novel techniques for modeling 3D cracks and their evolution in solids are presented. Cracks are modeled in terms of signed distance functions (level sets). Stress, strain and displacement field are determined using the extended finite elements method (X-FEM). Non-linear constitutive behavior for the crack tip region are developed within this framework to account for non-linear effect in crack propagation. Applications for static or dynamics case are provided.