scholarly journals Quantitative Acoustic Emission Fatigue Crack Characterization in Structural Steel and Weld

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Adutwum Marfo ◽  
Ying Luo ◽  
Chen Zhong-an
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Structural Steel ◽  
Crack Growth ◽  
Wavelet Packet ◽  
Growth Characteristics ◽  
Three Point Bending ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Frequency Feature

The fatigue crack growth characteristics of structural steel and weld connections are analyzed using quantitative acoustic emission (AE) technique. This was experimentally investigated by three-point bending testing of specimens under low cycle constant amplitude loading using the wavelet packet analysis. The crack growth sequence, that is, initiation, crack propagation, and fracture, is extracted from their corresponding frequency feature bands, respectively. The results obtained proved to be superior to qualitative AE analysis and the traditional linear elastic fracture mechanics for fatigue crack characterization in structural steel and welds.

Comparison of Theoretical Estimates and Experimental Measurements of Fatigue Crack Growth Under Severe Thermal Shock Conditions—Part I: Experimental Observations

1986 ◽  
Vol 108 (4) ◽  
pp. 501-506 ◽  
Author(s):  
D. Marsh ◽  
D. Green ◽  
R. Parker
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Thermal Cycle ◽  
Experimental Measurements ◽  
Linear Elastic ◽  
Elastic Fracture

This paper reports the results of an experiment in which a severe thermal cycle comprising of alternate upshocks and downshocks has been applied to an axisymmetric feature with an internal, partial penetration weld and crevice. The direction of cracking and crack growth rate were observed experimentally and detailed records made of the thermal cycle. A second part of the paper, reported separately, compares a linear elastic fracture mechanics assessment of the cracking to the experimental observations.

Numerical 3-D Fatigue Crack Growth Analyses of Real-Life Components

2010 ◽  
Author(s):  
Daniel Bremberg ◽  
Guido Dhondt
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Real Life ◽  
The Finite Element Method ◽  
Linear Elastic ◽  
Planar Crack ◽  
Elastic Fracture ◽  
Growth Analyses ◽  
Numerical Concept

This paper presents a numerical concept for fatigue crack propagation computations, within the theory of the finite element method and the theory of linear elastic fracture mechanics, capable of automatic analysis of curved 3-D crack fronts and non-planar crack surfaces. The general modelling of fatigue crack growth and the present algorithm based on a remeshing technique are described. A comparison to existing analytical solutions for an embedded elliptical crack shows satisfying agreement and a fatigue crack growth analysis of a real-life component illustrates the framework applicability.

Aspects of Fatigue Crack Growth

1988 ◽  
Vol 202 (1) ◽  
pp. 19-29 ◽  
Author(s):  
M W Brown
Keyword(s):  
Fatigue Crack ◽  
Crack Growth ◽  
High Cycle Fatigue ◽  
Fatigue Cracks ◽  
Cyclic Stress ◽  
Cycle Fatigue ◽  
Linear Elastic ◽  
Propagation Law ◽  
Elastic Fracture ◽  
Low Levels

The propagation of fatigue cracks under low levels of cyclic stress can be modelled by linear elastic fracture mechanics. Elastic-plastic parameters must be used for the higher stress amplitudes of conventional S–N curves in both the low and the high cycle fatigue regimes. The occurrence of different modes of crack growth is discussed and the use of a propagation law to predict component lifetime is demonstrated.

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