Author: Chan-Jiun JihPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Evaluation of Stress Intensity Factors by Finite Element Method
Author: Chan-Jiun JihEvaluation of Stress-Intensity Factors Using General Finite-Element Models
Author: IS. RajuPublisher:
ISBN:
Category : Bruchmechanik
Languages : en
Pages : 25
Book Description
Finite-element methods are commonly used to evaluate cracked solids. Post-processing methods are used to extract Mode I stress-intensity factor values from finite-element analyses. These methods include the Crack-Opening-Displacement (COD) method, the Force method, the Virtual Crack Closure Technique (VCCT) and the Equivalent Domain Integral (EDI) method. The COD method, Force method and the VCCT appear to require that the finite-element mesh intersect the crack front in an orthogonal manner in order to obtain accurate stress-intensity factor values. The EDI does not appear to require this orthogonality with the crack front to obtain accurate stress intensity factor values. The objectives of this study are to determine if accurate stress intensity factor values can be obtained from finite-element models that lack orthogonality with the crack front and, if accurate values cannot be obtained, to modify the extraction methods so that accurate stress-intensity factor values can be obtained from models without orthogonality at the crack front.
A Re-evaluation of Finite-element Models and Stress-intensity Factors for Surface Cracks Emanating from Stress Concentrations
Author: Evaluation of Stress Intensity Factors in Multi-cracked Thick-walled Cylinders Using Finite Element Methods
Author: Kenneth James KirkhopePublisher:
ISBN:
Category : Cylinders
Languages : en
Pages : 328
Book Description
Evaluation of Stress Intensity Factors for Crack Interaction Problems Using a Finite Element Alternating Method
Author: Michael Robert KratochwillPublisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 410
Book Description
Evaluation of Stress Intensity Factors in Multi-cracked Thick-walled Cylinders Using Finite Element Methods
Author: Kenneth James KirkhopePublisher:
ISBN:
Category : Cylinders
Languages : en
Pages : 0
Book Description
A 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...
Evaluation of Bimaterial Stress Intensity Factors Using the Finite Element-boundary Element Alternating Method
Author: Siddhartha LahiriEvaluation of Stress Intensity Factors by a Self-adaptive Finite Element Scheme
Author: Giovanni CavalliniPublisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 12
Book Description
Evaluation of Finite-Element Models and Stress-Intensity Factors for Surface Cracks Emanating from Stress Concentrations
Author: JC. NewmanPublisher:
ISBN:
Category : Boundary-layer region
Languages : en
Pages : 15
Book Description
This paper presents an evaluation of the three-dimensional finite-element models and methods used to analyze surface cracks at stress concentrations. 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 semicircular 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.