Ductile fracture processes in 7075 aluminum

1995 ◽  
Vol 26 (2) ◽  
pp. 407-415 ◽  
Author(s):  
C. P. You ◽  
A. W. Thompson ◽  
I. M. Bernstein
Keyword(s):  
Ductile Fracture ◽  
Fracture Processes

Application of Constraint-Sensitive Fracture Mechanics to the Assessment of Girth Weld Integrity

2004 ◽  
Author(s):  
Yong-Yi Wang ◽  
Ming Liu ◽  
David Horsley
Keyword(s):  
Fracture Mechanics ◽  
Ductile Fracture ◽  
Experimental Evidence ◽  
Practical Application ◽  
Constraint Effect ◽  
Potential Applications ◽  
Constraint Effects ◽  
Assessment Procedures ◽  
Cracked Specimens ◽  
Fracture Processes

It has been known since the 1960’s that the crack-tip fields of specimens containing sharp cracks depend on the mode of loading. Experimental evidence has shown that cracked specimens loaded in bending have lower toughness than the same material loaded in tension. This phenomenon has been attributed to the “constraint effect” on fracture. Modern constraint-sensitive fracture mechanics has brought about fundamental theoretical understandings on the constraint effects. The constraint-sensitive fracture mechanics has moved from academic circles to practical application, as evident by a number of recently published fitness-for-service (FFS) assessment procedures that incorporates the constraint effects. This paper reviews the developments in constraint-sensitive fracture mechanics with the focus on its potential applications to the assessment of pipeline girth weld integrity. The review covers (1) constraint theories and experimental evidences, (2) constraint models for brittle and ductile fracture, and (3) limitations of current constraint models. The paper closes with thoughts on the applications of the constraint models and theories to ductile fracture processes, which are the most relevant to modern linepipes and their welds.

Interaction Effect Evaluation of Multiple Through Cracks in Ductile Fracture Process

2012 ◽  
Author(s):  
Kazuhiro Suga ◽  
Katsumasa Miyazaki ◽  
Yohei Arai ◽  
Masanori Kikuchi
Keyword(s):  
Ductile Fracture ◽  
Interaction Effect ◽  
Maximum Load ◽  
Initial Crack ◽  
Multiple Cracks ◽  
Horizontal Distance ◽  
Effect Evaluation ◽  
Ductile Crack Growth ◽  
Fracture Processes ◽  
Ductile Fracture Process

Study on the interaction effect of multiple cracks on the collapse load during ductile crack growth processes is important for the integrity evaluation of nuclear structure. The ductile fracture processes are well studied numerically by using Gurson’s constitutive equation and taking into account of void growth during plastic deformation. In this study, two through cracks are assumed to exist in a flat plate in tension and the interaction between two cracks is studied. The initial crack length, horizontal distance and vertical distance between two cracks are changed systematically. The interaction behavior between two cracks is studied precisely. Criteria to evaluate maximum load in the ductile fracture processes are discussed. The present study found H/l criteria can estimate the maximum load reasonably, and also the consideration of the effect of the horizontal distance between two cracks in H/l criteria may improve its estimation more reasonable. The effects on maximum load by changing the horizontal distance between two cracks are studied.

Ductile Fracture Simulation of Mulitple Surface Flaws

2011 ◽  
Author(s):  
Kazuhiro Suga ◽  
Katsumasa Miyazaki ◽  
Ryotaro Senda ◽  
Masanori Kikuchi
Keyword(s):  
Ductile Fracture ◽  
Fracture Behavior ◽  
Tensile Load ◽  
Crack Interaction ◽  
Cracked Plates ◽  
Fracture Simulation ◽  
Crack Problems ◽  
Surface Flaws ◽  
Fracture Processes ◽  
Effect Of Surface

Effect of surface flaw on ductile fracture behavior of non-aligned multiple flaws in plate is studied numerically using Gurson’s constitutive equation. Based on experiments, 2 parallel crack problems are simulated. In experiments and simulation crack coalescence, crack non coalescence and crack interaction was observed. In all cases, ductile fracture processes are obtained and results are compared with experimental ones. In this study, a new alignment rule for the prediction of maximum tensile load or rupture load for multiple cracked plates is compared with the simulation result.

Acoustic emission interpretation of ductile fracture processes

1979 ◽  
Vol 15 (6) ◽  
pp. 491-514 ◽  
Author(s):  
W. W. Gerberich ◽  
M. Stout ◽  
K. Jatavallabhula ◽  
D. Atteridge
Keyword(s):  
Acoustic Emission ◽  
Ductile Fracture ◽  
Fracture Processes

Simulation of Ductile Fracture for Multiple Flaws

2010 ◽  
Author(s):  
Masanori Kikuchi ◽  
Kazuhiro Suga ◽  
Shota Kawasaki
Keyword(s):  
Constitutive Equation ◽  
Ductile Fracture ◽  
Interaction Effect ◽  
Evaluation Method ◽  
Crack Problem ◽  
Fracture Pattern ◽  
Crack Coalescence ◽  
Multiple Cracks ◽  
Parallel Cracks ◽  
Fracture Processes

Interaction effect of multiple flaws on ductile fracture is studied numerically by using Gurson’s constitutive equation. Based on experiments, 2 parallel cracks problems and 3 parallel cracks problems are simulated. In some problems, crack coalescence does not occur, and it occurs in other cases. In all cases, ductile fracture processes are obtained, and results are compared with experimental ones. Fracture pattern and load-displacement curves agree well with experiments. It is shown that void growth term is dominant for the coalescence of cracks. Slanted crack problem and non-uniform length crack problem are simulated and evaluation method of multiple cracks problem is discussed.

Interaction Effect Evaluation of Plural Surface Cracks in Ductile Fracture Process

2012 ◽  
Author(s):  
Kazuhiro Suga ◽  
Katsumasa Miyazaki ◽  
Ryotaro Senda ◽  
Masanori Kikuchi
Keyword(s):  
Ductile Fracture ◽  
Fracture Process ◽  
Crack Depth ◽  
Maximum Load ◽  
Crack Penetration ◽  
Crack Problems ◽  
Average Crack ◽  
Fracture Processes ◽  
Ductile Fracture Process ◽  
Effect Of Surface

Effect of surface flaw on ductile fracture behavior of non-aligned multiple flaws in plate is studied numerically using Gurson’s constitutive equation. Based on experiments, two parallel non-aligned crack problems are simulated. From experimental and simulation data, crack coalescence, interaction between two cracks and crack penetration was observed. In all cases, ductile fracture processes are obtained and results are compared with experimental ones. Fracture patterns agree well with experimental results. Close qualitative match was obtained by comparing each load displacement curves that are normalized by maximum load. It shows that the mechanism of ductile fracture process is properly captured. By selecting one normalized experimental data as a base setup, maximum load from related simulation results can be predicted. Aligned rules are checked based on these simulations, and H / a criteria verified it’s availability when average crack depth is used as crack depth.

Simulation of Ductile Fracture of Multiple Flaws

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Kazuhiro Suga ◽  
Masanori Kikuchi ◽  
Shota Kawasaki
Keyword(s):  
Constitutive Equation ◽  
Ductile Fracture ◽  
Void Growth ◽  
Evaluation Method ◽  
Fracture Pattern ◽  
Experimental Results ◽  
Load Displacement ◽  
Fracture Processes

The effect of the interaction of multiple flaws on ductile fracture is studied numerically by Gurson’s constitutive equation. Based on experimental results, two parallel flaw and three parallel flaw problems are simulated. Flaw coalescence does not occur in some problems but does occur in other cases. In all cases, ductile fracture processes are obtained, and the results are compared with the experimental results. The fracture pattern and load-displacement curves agree well with the experimental results. The void growth term is found to be dominant for the coalescence of flaws. The slant flaw problem and the nonuniform length flaw problem are simulated and an evaluation method for the multiple flaws problem is discussed.

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