Application of Equivalent CTOD Ratio to Fracture Assessment of Structural Components

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Satoshi Igi ◽  
Mitsuru Ohata ◽  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Large Scale ◽  
Steel Structures ◽  
Evaluation Procedure ◽  
Structural Components ◽  
Steel Component ◽  
Application Procedure ◽  
Edge Surface ◽  
Toughness Evaluation ◽  
Fracture Assessment

Plastic constraint correction using the equivalent CTOD concept has been studied in the International Standardization of Fracture Toughness Evaluation Procedure for Fracture Assessment of Steel Structures project. This project was carried out over a 3-year period with the foundation of the Japanese Ministry of Economy, Trade, and Industry, and the results were summarized in a draft standard “Method of constraint loss correction of CTOD fracture toughness for fracture assessment of steel component.” Equivalent CTOD ratio β is proposed in terms of the constraint loss correction between the fracture performance of steel structures and fracture toughness tests using the Weibull stress as the driving force of the brittle fracture. This paper provides the application procedure of equivalent CTOD ratio to the fracture assessment of structural components. Equivalent CTOD ratio was taken in the failure assessment diagram, and discussed the applicability by comparison with large scale test results of structural component such as edge surface crack panel, center through-wall crack panel, and other geometries.

Application of Equivalent CTOD Ratio to Fracture Assessment of Structural Components

2008 ◽  
Author(s):  
Satoshi Igi ◽  
Mitsuru Ohata ◽  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Large Scale ◽  
Steel Structures ◽  
Structural Components ◽  
Steel Component ◽  
Draft Standard ◽  
Application Procedure ◽  
Edge Surface ◽  
Fracture Assessment ◽  
Scale Test

Plastic constraint correction using the equivalent CTOD concept has been studied in the IST project. This project was carried out over a 3-year period with the foundation of METI in Japan, and the results were summarized in a draft standard, “Method of constraint loss correction of CTOD fracture toughness for fracture assessment of steel component.” Equivalent CTOD ratio β is proposed in terms of constraint loss correction between the fracture performance of steel structures and fracture toughness tests using the Weibull stress as the driving force of brittle fracture. This paper provides the application procedure of Equivalent CTOD ratio to the fracture assessment of structural components. Equivalent CTOD ratio was taken in the fracture assessment diagram, and discussed the applicability by comparison with large scale test result of structural component such as Edge Surface Crack Panel, Center Through-wall crack panel and so on.

Analysis on Critical CTOD of Long-Term Used Penstock

2017 ◽  
Vol 741 ◽  
pp. 57-62
Author(s):  
Fumito Kawamura ◽  
Masazumi Miura ◽  
Ryuichiro Ebara ◽  
Keiji Yanase
Keyword(s):  
Fracture Toughness ◽  
Structural Integrity ◽  
Steel Structures ◽  
Chemical Compositions ◽  
Structural Components ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Critical Crack ◽  
Crack Tip Opening

Many studies have been conducted to characterize the fracture toughness of structural steels and their welded joints. However, most studies focus on newly developed steels, and the number of studies on the fracture toughness of long-term used steels in structural components is rather limited. Furthermore, a lack of data on the fracture toughness causes difficulties in evaluating the structural integrity of existing steel structures. In this study, CTOD tests were performed to characterize the fracture toughness of penstock that has been in service for 50 years. By measuring the critical crack tip opening displacement in conjunction with analysis for chemical compositions, the characteristics of fracture toughness were investigated.

scholarly journals Fracture Assessment of Weld Joints of High-Strength Steel in Pre-Strained Condition

2019 ◽  
Vol 9 (7) ◽  
pp. 1306
Author(s):  
Gyubaek An ◽  
Jeongung Park ◽  
Mituru Ohata ◽  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Welded Joints ◽  
Steel Structures ◽  
Great Earthquake ◽  
Small Scale ◽  
Ship Structures ◽  
Strained Condition ◽  
Critical Fracture ◽  
Fracture Assessment ◽  
Unstable Fractures

Unstable fractures tend to occur after ductile crack initiation or propagation. In most collapsed steel structures, a maximum 15% pre-strain was recorded, at the steel structural connections, during the great earthquake of 1995, in Japan. Almost-unstable fractures were observed in the beam-to-column connections, where geometrical discontinuities existed. Structural collapse and unstable failure occurred after large-scale plastic deformations. Ship structures can also suffer from unstable fractures in the welded joints. The fracture resistance of butt-welded joints subjected to tension in the pre-strained condition was estimated by considering the toughness deterioration, due to pre-strain and toughness correction for constraint loss in a tension specimen. The target specimen for this fracture assessment was a double-edged, through-thickness crack panel, with a crack in the weld joint (heat-affected zone (HAZ)). The critical fracture toughness value (crack tip opening displacement (CTOD)) of a large structure with pre-strain, which was applied to the HAZ region, was estimated from a small-scale, pre-stained, three-point bend specimen. Fracture toughness values, evaluated by a CTOD test, were recently mandated for shipbuilding steel plates. The critical fracture toughness value is a very useful parameter to evaluate the safety of huge ship structures.

Equivalent CTOD Concept for Correction of CTOD Toughness for Constraint Loss in Steel Weld Components

2012 ◽  
Vol 706-709 ◽  
pp. 97-104
Author(s):  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Assessment Method ◽  
Weld Strength ◽  
Steel Weld ◽  
Structural Components ◽  
Conventional Procedure ◽  
Failure Assessment ◽  
Fracture Assessment ◽  
Weibull Stress ◽  
Fracture Toughness Specimen

This paper presents a new fracture assessment method, IST method developed as ISO 27306. The IST method implements an equivalent CTOD ratio,β, for the CTOD toughness correction for constraint loss in structural components. Usingβ, the standard fracture toughness specimen and structural components are linked at the same level of the Weibull stress. This paper extends the equivalent CTOD concept to weld components. Effects of the weld strength mismatch and residual stress onβare discussed. It is shown on the failure assessment diagram (FAD) that the CTOD toughness correction withβleads to accurate fracture assessments of weld panels, whereas the conventional procedure gives much conservative results.

Japanese Research Activities on Offshore Fracture Mechanics Applications

1988 ◽  
Vol 41 (2) ◽  
pp. 96-106 ◽  
Author(s):  
S. Machida ◽  
H. Yajima ◽  
M. Toyosada ◽  
Y. Hagiwara ◽  
K. Kajimoto
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Structural Integrity ◽  
Local Strain ◽  
Practical Method ◽  
Offshore Structures ◽  
Structural Components ◽  
Research Activities ◽  
Fracture Assessment ◽  
Size Evaluation

The brittle fracture, for its catastrophic nature, is one of the most important factors for designing offshore structures especially operating in the cold sea. Fracture mechanics method can provide a useful tool to maintain the reliability of structural integrity. This paper gives descriptions on a proposed method for fracture assessment with experimental verifications, and also informations from some recent Japanese research activities associated with the application of fracture mechanics to the offshore structures, i.e. initial defect size evaluation, a practical method for evaluation of the local strain in strain concentrated structural components, effect of strain rate on fracture toughness and fracture toughness of weldments.

RUUKKI RAEX 300

Alloy Digest ◽  
2012 ◽  
Vol 61 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Shear Strength ◽  
Impact Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Structural Components ◽  
Wear Resistant

Abstract RUUKKI RAEX 300 (typical yield strength 900 MPa) is part of the Raex family of high-strength and wear-resistant steels with favorable hardness and impact toughness to extend life and decrease wear in structural components. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on wear resistance as well as forming, machining, and joining. Filing Code: SA-643. Producer or source: Rautaruukki Corporation.

CYCLOPS BHT

Alloy Digest ◽  
1965 ◽  
Vol 14 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Elevated Temperature ◽  
High Speed ◽  
High Speed Steel ◽  
High Strength ◽  
Heat Treating ◽  
High Load ◽  
Structural Components ◽  
Temperature Performance

Abstract Cyclops BHT is a low-alloy martensitic high-speed steel of the molybdenum type recommended for high strength, high load structural components designed for elevated temperature service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-173. Producer or source: Cyclops Corporation.

DOMEX 110XF

Alloy Digest ◽  
2003 ◽  
Vol 52 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength Steel ◽  
Civil Engineering ◽  
High Strength ◽  
Heat Treating ◽  
Bend Strength ◽  
Structural Components ◽  
Very High

Abstract Domex 110XF is a very-high-strength steel that is used for automotive and civil engineering structural components. This datasheet provides information on composition, physical properties, hardness, tensile properties, and bend strength as well as fracture toughness. It also includes information on heat treating and joining. Filing Code: SA-512. Producer or source: SSAB Swedish Steel Inc.

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