Application of Micromechanical Models to the Analysis of Ductile Fracture Under Dynamic Loading

2009 ◽  
pp. 343-343-15 ◽  
Author(s):  
D-H Sun ◽  
A Hönig ◽  
W Böhme ◽  
W Schmitt
Keyword(s):  
Ductile Fracture ◽  
Dynamic Loading ◽  
Micromechanical Models

scholarly journals An overview of application of micromechanical models in ductile fracture analysis of welded joints

2020 ◽  
Vol 47 (1) ◽  
pp. 33-62
Author(s):  
M. Rakin ◽  
B. Medjo ◽  
N. Gubeljak ◽  
A. Sedmak
Keyword(s):  
Ductile Fracture ◽  
Welded Joints ◽  
Void Nucleation ◽  
Base Material ◽  
Damage Parameter ◽  
Damage Development ◽  
Long Time ◽  
Actual Material ◽  
Micromechanical Models

Fracture of welded joints has been an important research and industrial topic for a long time, having in mind the key role of welded joints in ensuring the safe operation and integrity of welded structures. This work contains an overview of application of micromechanical models to ductile fracture of welded joints. The main benefit of these models, in comparison with the classical fracture mechanics approach, is consideration of the local quantities (stress and strain) in prediction of damage development. The damage is quantified through the value of the damage parameter, which is typically related to the void nucleation, growth and coalescence for ductile fracture of metallic materials, i.e. the description of the material can be related to the actual material behaviour during fracture. Most of the presented studies, including those published by the present authors, are performed on steel as the base material, and the rest deal with aluminium alloys.

On the Use of Side-Grooves in Estimating JIc Fracture Toughness With Charpy-Size Specimens

1980 ◽  
Vol 102 (2) ◽  
pp. 192-199 ◽  
Author(s):  
W. L. Server ◽  
R. A. Wullaert ◽  
R. O. Ritchie
Keyword(s):  
Fracture Toughness ◽  
Ductile Fracture ◽  
Dynamic Loading ◽  
Pressure Vessel ◽  
Crack Opening ◽  
Test Procedure ◽  
Maximum Load ◽  
Loading Rates ◽  
Surveillance Programs ◽  
Static And Dynamic Loading

The problem of obtaining a meaningful value of toughness from small Charpy-size surveillance specimens, tested at temperature corresponding to the upper shelf where ductile fracture predominates, is investigated. Following the procedures of Green and Knott for measurement of crack opening displacements at initiation of ductile fracture, a test procedure is adopted in which small precracked Charpy-size bend specimens are side-grooved to increasing depths and tested to failure under both quasi-static and dynamic loading rates. Values of the J-contour integral at maximum load (Jmax) for specimens side-grooved in excess of 30 percent are found to agree, within acceptable limits, with “valid” initiation JIc fracture toughness values determined independently using multi-specimen resistance-curve techniques. Three nuclear pressure vessel materials (two base metals, SA533B-1 and SA302B, and a submerged arc weld metal) were evaluated at temperatures between 71 and 177° C, which correspond to upper shelf temperatures. The test procedure described offers a simple, inexpensive, small specimen compromise for estimating the fracture toughness at the onset of ductile fracture from a single Charpy-size bend test piece for both quasi-static and dynamic loading rates. This approach could be readily adopted in nuclear surveillance programs for toughness evaluation of unirradiated and neutron irradiated pressure vessel steels.

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