A generalized weakest-link model for size effect on strength of quasi-brittle materials

2017 ◽  
Vol 53 (2) ◽  
pp. 1227-1245 ◽  
Author(s):  
Wei-Sheng Lei
Keyword(s):  
Size Effect ◽  
Brittle Materials ◽  
Weakest Link ◽  
Link Model

scholarly journals DEPENDENCE OF CREEP FAILURE PROBABILITY ON THE SIZE OF METALLIC SPECIMENS

2013 ◽  
Vol 7 (3) ◽  
pp. 166-169
Author(s):  
Krzysztof Nowak
Keyword(s):  
Size Effect ◽  
Scale Effect ◽  
Failure Probability ◽  
Experimental Verification ◽  
Experimental Analysis ◽  
Numerical Models ◽  
Creep Failure ◽  
Weakest Link ◽  
Link Model

Abstract The occurrence of statistical size effect is considered for damage in creep conditions. The numerical and experimental analysis have been performed. The obtained results are ambiguous. Numerical models confirm the scale effect which can be statistical or deterministic one. But this effect has no experimental verification. It may suggest that the weakest link model cannot be applied in creep conditions. Explanation of this needs further investigations

THE SIZE EFFECT OF MICROSTRUCTURAL IMPLICATIONS OF THE WEAKEST LINK MODEL

1990 ◽  
Vol 13 (3) ◽  
pp. 185-200 ◽  
Author(s):  
A. Brückner-Foit ◽  
W. Ehl ◽  
D. Munz ◽  
B. Trolldenier
Keyword(s):  
Size Effect ◽  
Weakest Link ◽  
Link Model

A Mathematical Model for Competing Failure Modes in Strain Cycle Fatigue

2006 ◽  
Vol 129 (2) ◽  
pp. 293-303 ◽  
Author(s):  
Gerald T. Cashman
Keyword(s):  
Failure Modes ◽  
High Stress ◽  
Local Strain ◽  
Initiation Site ◽  
Weakest Link ◽  
Strain Relationship ◽  
Powder Metallurgy Alloy ◽  
Link Model ◽  
Cyclic Plastic Strain ◽  
Selection Of

Elevated temperature data for powder metallurgy alloy René 95 generated in vacuum are presented to demonstrate that the life differences observed between surface and internally initiated failures are due to an environmental effect. The transition in behavior from a mode at low stress dominated by internal initiations to a surface dominated mode at high stress is quantitatively described in terms of both a weakest-link model and a local strain relationship. A fatigue failure mechanism is provided that explains that the natural selection of initiation site is based upon the concept that the site displaying the highest local cyclic plastic strain is the location where fatigue initiates.

Reliability of Welded Structures Containing Cracks in Heat-Affected Zones

2000 ◽  
Vol 122 (4) ◽  
pp. 225-232 ◽  
Author(s):  
David B. Lanning ◽  
M.-H. Herman Shen
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Crack Front ◽  
Surface Crack ◽  
Material Properties ◽  
Coarse Grained ◽  
Welded Structures ◽  
Weakest Link ◽  
Link Model

This study investigates the reliability of a plate containing a semi-elliptical surface crack intersecting regions of dissimilar material properties. A weakest-link model is developed to express fracture toughness distributions in terms of effective crack lengths that account for the varying stress intensity factor along the crack front. The model is intended to aid in the development of fracture toughness distributions for cracks encountering local brittle zones (LBZ) in the heat-affected zones (HAZ) of welded joints, where lower-bound fracture toughness values have been measured in the laboratory when a significant portion of the crack front is intersecting the coarse-grained LBZs. An example reliability analysis is presented for a surface crack in a material containing alternating bands of two Weibull-distributed toughnesses. [S0892-7219(00)01203-6]

scholarly journals Fatigue strength characterization of Al-Si cast material incorporating statistical size effect

2018 ◽  
Vol 165 ◽  
pp. 14002 ◽  
Author(s):  
Roman Aigner ◽  
Martin Leitner ◽  
Michael Stoschka
Keyword(s):  
Size Effect ◽  
Extreme Value Distribution ◽  
Ct Scanning ◽  
Element Analysis ◽  
Cast Material ◽  
Stressed Volume ◽  
Alloy Casting ◽  
Weakest Link ◽  
Testing Region ◽  
Strength Characterization

Cast aluminium components may exhibit material imperfections such as shrinkage and gas pores, or oxide inclusions. Therefore, the fatigue resistance is significantly influenced by the size and location of these inhomogenities. In this work, two different specimen geometries are manufactured from varying positions of an Al-Si-Cu alloy casting. The specimen geometries are designed by means of shape optimization based on a finite element analysis and exhibit different highly-stressed volumes. The numerically optimized specimen curvature enforces a notch factor of only two percent. To enable the evaluation of a statistical size effect, the length of the constant testing region and hence, the size of the highly-stressed volume varies by a ratio of one to ten between the two specimen geometries. Furthermore, the location of the crack initiation is dominated by the comparably greatest defects in this highly-stressed volume, which is also known as Weibull’s weakest link model. The crack initiating defect sizes are evaluated by means of light microscopy and modern scanning electron microscope methods. Finally, the statistical size effect is analysed based on the extreme value distribution of the occurring defects, whereby the size and location of the pores is non-destructively obtained by computed tomography (CT) scanning. This elaborated procedure facilitates a size-effect based methodology to study the defect distribution and the associated local fatigue life of CPS casted Al-Si lightweight components.

Sign in / Sign up

Export Citation Format

Share Document