Symmetric Galerkin Boundary Element Analysis in Three-Dimensional Linear-Elastic Fracture Mechanics

2005 ◽  
pp. 315-344
Author(s):  
A. Frangi ◽  
G. Maier ◽  
G. Novati ◽  
R. Springhetti
Keyword(s):  
Fracture Mechanics ◽  
Boundary Element ◽  
Three Dimensional ◽  
Linear Elastic Fracture Mechanics ◽  
Element Analysis ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Boundary Element Analysis

Application of the Finite Element Method to Linear Elastic Fracture Mechanics

1991 ◽  
Vol 44 (10) ◽  
pp. 447-461 ◽  
Author(s):  
Leslie Banks-Sills
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Displacement Field ◽  
Three Dimensional ◽  
Linear Elastic Fracture Mechanics ◽  
The Finite Element Method ◽  
Linear Elastic ◽  
Elastic Fracture

Use of the finite element method to treat two and three-dimensional linear elastic fracture mechanics problems is becoming common place. In general, the behavior of the displacement field in ordinary elements is at most quadratic or cubic, so that the stress field is at most linear or quadratic. On the other hand, the stresses in the neighborhood of a crack tip in a linear elastic material have been shown to be square root singular. Hence, the problem begins by properly modeling the stresses in the region adjacent to the crack tip with finite elements. To this end, quarter-point, singular, isoparametric elements may be employed; these will be discussed in detail. After that difficulty has been overcome, the stress intensity factor must be extracted from either the stress or displacement field or by an energy based method. Three methods are described here: displacement extrapolation, the stiffness derivative and the area and volume J-integrals. Special attention will be given to the virtual crack extension which is employed by the latter two methods. A methodology for calculating stress intensity factors in two and three-dimensional bodies will be recommended.

scholarly journals FATIGUE LIFE ANALYSIS OF RAIL-WELDS USING LINEAR ELASTIC FRACTURE MECHANICS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Mequanent M. Alamnie ◽  
Yalelet Endalemaw
Keyword(s):  
Fatigue Life ◽  
Fracture Mechanics ◽  
Fatigue Cracks ◽  
High Stress ◽  
Fatigue Cracking ◽  
Linear Elastic Fracture Mechanics ◽  
Frequency Interval ◽  
Element Analysis ◽  
Linear Elastic ◽  
Elastic Fracture

The initiation and growth of fatigue cracking is mainly due to high stress concentration, heterogeneity and poor quality of weld. The detection and rectification of such weld defects are major concerns of rail network managers to reduce potential risk of rail breaks and derailments. To estimate the fatigue life of welded joints and to analyze the progress of fatigue cracks, a fracture mechanics-based analysis and fatigue models were developed using Finite Element Analysis. The initial flaw is obtained from a sample weld using ultrasonic flaw detecting machine test. Linear Elastic Fracture Mechanics (LEFM) approach based on the Paris law was applied to determine critical crack size and the number of cycles to failure using FRANC3D software. The inspection interval of rail welds before fracture (failure) was suggested based on reliability and life cycle analysis that correspond with minimum overall cost and frequency interval. It is recommended that fracture-based models in combination with reliability analyses can be a sustainable infrastructure decision-making algorithm.

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