Quantification of the Material Ductility Effect on Notch Fracture Toughness Using Numerical Damage Analysis Method

2020 ◽  
Author(s):  
Eui-kyun Park ◽  
Gyo-Geun Youn ◽  
Yun-Jae Kim ◽  
Masayuki Kamaya
Keyword(s):  
Fracture Toughness ◽  
Fracture Resistance ◽  
Damage Model ◽  
Fe Analysis ◽  
Damage Analysis ◽  
Notch Radius ◽  
Cold Worked ◽  
Axial Fracture ◽  
Material Ductility ◽  
The Relationship

Abstract In this study, the finite element (FE) damage analysis based on the multi-axial fracture strain model was applied to investigate the effect of the material ductility on fracture resistance of notched defect. (The fracture toughness is used only for a cracked specimen and the fracture resistance is used for notched specimens throughout the paper.) To obtain the material property with different ductility, the tensile and fracture toughness tests of the cold-worked SUS316 were used. The damage model was determined from comparing the experimental data with simulated FE analysis results. Then the FE analysis was applied to calculate the fracture resistance according to the notch radius in each material. It shows that the slope of initiation resistance according to the notch radius was related to the material ductility. To quantify this effect of ductility, the relationship between notch fracture resistance and material tensile properties was confirmed.

J-R Curve Prediction of Pre-Strained Stainless Steel 316 Material Using FE Damage Analysis Method

2018 ◽  
Author(s):  
Jun-Min Seo ◽  
Ji-Soo Kim ◽  
Yun-Jae Kim
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Damage Model ◽  
Damage Analysis ◽  
Fracture Toughness Test ◽  
Toughness Test ◽  
Cold Worked ◽  
Axial Fracture ◽  
Stainless Steel 316 ◽  
Strain Model

In this study, a method to predict J-R curve of SUS316 material using FE damage analysis is proposed. As experimental data, tensile and fracture toughness test results of cold worked SUS316 are used. The damage model used in this study is multi-axial fracture strain model and the model is determined by simulating the tensile and fracture toughness test according to the procedure in R6 code [1]. A pre-strain constant is newly introduced to consider pre-strain damage caused by the pre-strain, and the damage for various degrees of pre-strain are calculated. As a result, the predicted J-R curves using FE damage model show good agreement with the experimental data.

On notch fracture mechanics

2021 ◽  
Vol 87 (2) ◽  
pp. 56-64
Author(s):  
G. Pluvinage
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Plastic Zone ◽  
Fracture Resistance ◽  
Notch Radius ◽  
Notch Stress Intensity Factor ◽  
Blunt Notch ◽  
Notch Stress

Different stress distributions for an elastic behavior are presented as analytical expressions for an ideal crack, a sharp notch and a blunt notch. The elastic plastic distribution at a blunt notch tip is analyzed. The concept of the notch stress intensity factor is deduced from the definition of the effective stress and the effective distance. The impacts of the notch radius and constraint on the critical notch stress intensity factor are presented. The paper ends with the presentation of the crack driving force Jρ for a notch in the elastic case and the impact of the notch radius on the notch fracture toughness Jρ,c. The notch fracture toughness Jρ,c is a measure of the fracture resistance which increases linearly with the notch radius due to the plastic work in the notch plastic zone. If this notch plastic zone does not invade totally the ligament, the notch fracture toughness Jρ,c is constant. This occurs when the notch radius is less than a critical one and there is no need to use the cracked specimen to measure a lower bound of the fracture resistance.

Energy-based numerical modeling of the strain rate effect on fracture toughness of SA508 Gr. 1a

2017 ◽  
Vol 52 (3) ◽  
pp. 177-189 ◽  
Author(s):  
Hyun-Suk Nam ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim ◽  
Jong-Sung Kim
Keyword(s):  
Fracture Toughness ◽  
Strain Rate ◽  
Damage Model ◽  
Type Model ◽  
Fracture Toughness Test ◽  
Ductile Tearing ◽  
Rate Dependent ◽  
Energy Concept ◽  
Axial Fracture ◽  
Dynamic Loading Conditions

This article presents an energy-based method to simulate ductile tearing under dynamic loading conditions. The strain rate–dependent material properties are characterized by the Johnson–Cook-type model. The damage model is defined based on the multi-axial fracture strain energy concept. The proposed damage model is applied to simulate the fracture toughness test of SA508 Gr. 1a under four different test speeds. Simulated results show a good overall agreement with the experimental results.

Fracture Mechanics Study on the Effects of Various Notch Radii by Using FE Analysis

2015 ◽  
Author(s):  
Zalikha Murni Abdul Hamid ◽  
Keun-Hyung Bae ◽  
Gyo-Geun Youn ◽  
Dae-Young Lee ◽  
Yun-Jae Kim ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Fracture Strain ◽  
Notch Root ◽  
Damage Model ◽  
Fe Analysis ◽  
Experiment Data ◽  
Apparent Fracture Toughness ◽  
Notch Root Radius ◽  
Plane Strain Deformation

This paper predicts the effects of notch root radius on the ductile fracture behavior of the structure through evaluation based on fracture mechanics concept. To understand the effects of notch radii on structure, FE analysis of J-integral for plane strain deformation fields with various size of notches were predicted. The fracture toughness of the specimens with various notch radii were determined by stress modified fracture strain damage model FE simulation that was established based on notched bar tensile test data. The simulated results were validated by comparison with the experiment data. Findings show that the value of apparent fracture toughness increases with the increase in the notch radii. Therefore, indicates the increase in the resistance to the crack propagation. Similar trend can be shown for both C(T) and M(T) specimen. Thus, shows that the proposed method can be used to obtain effects of various notch radii.

Comparison of J Resistance Curves From Toughness Testing Specimens With Those From Various Cracked Pipe Tests

2013 ◽  
Author(s):  
Jong-Hyun Kim ◽  
Jae-Jun Han ◽  
Yun-Jae Kim ◽  
Do-Jun Shim
Keyword(s):  
Damage Model ◽  
Fe Analysis ◽  
Contour Integral ◽  
Damage Analysis ◽  
Resistance Curve ◽  
Size Dependent ◽  
Element Size ◽  
Toughness Testing ◽  
Resistance Curves ◽  
J Estimation

J contour integral still has great importance to predict fracture of both small specimen and full-scaled pipes. However, it is difficult to obtain experimental J resistance curve of full-scaled pipes due to the differences of defect shape and complexity of loads. Due to the recent development of the FE damage analysis to predict fracture of full-scaled pipes, it is also possible to predict J resistance of full-scaled pipes. To use this FE damage model for fracture estimation, it is necessary to verify the validity of this model by compared with toughness testing specimens. In this paper, J resistance curves of full-scaled pipes using FE damage analysis were compared with various toughness testing specimens from Pipe Fracture Encyclopedia performed by Battelle. And the J contour integral were calculated from FE analysis using the element-size-dependent damage model recently proposed by the authors. Compared results showed that J calculation using FE damage analysis could be used for J-estimation of full-scaled pipes by compared with fracture toughness testing specimens.

FE Analysis and Experimental Investigation of Cracked and Un-Cracked Thin-Walled Tubular Components to Evaluate Mechanical and Fracture Properties

2017 ◽  
pp. 266-293
Author(s):  
M.K. Samal
Keyword(s):  
Fracture Resistance ◽  
Damage Model ◽  
Crack Growth Behavior ◽  
Type Specimens ◽  
Element Analysis ◽  
Fracture Properties ◽  
Thin Walled ◽  
Suitable Standard ◽  
Axial Fracture ◽  
Tubular Components

For investigation of fracture behavior and assessment of remaining life of critical thin-walled tubular components in industry, the transverse mechanical property and the axial fracture properties are essential. However, evaluation of these properties by machining suitable standard specimens from these components directly and subjecting them to standard tests is usually not feasible. In this chapter, the nonlocal version of the Rousselier's damage model has been used to predict the fracture resistance behavior of double-edged-notched-tensile specimens made from Zircaloy-4 material. Initially, the micro-mechanical parameters have been determined from the testing of ring-type specimens. Subsequently, these parameters were used in finite element analysis of the double-edged-notched-tensile specimen in order to predict the crack growth behavior and the crack path under applied displacement-controlled loading conditions. The fracture resistance behavior obtained in terms of J-R curve was also compared with the corresponding J-R curves of axially-cracked pin-loading-tension specimens.

scholarly journals Fracture toughness design in horse hoof keratin

1986 ◽  
Vol 125 (1) ◽  
pp. 29-47 ◽  
Author(s):  
J. E. Bertram ◽  
J. M. Gosline
Keyword(s):  
Fracture Toughness ◽  
Fracture Resistance ◽  
Tensile Tests ◽  
Compact Tension ◽  
J Integral ◽  
Morphological Organization ◽  
Strain Behaviour ◽  
Weak Plane ◽  
Equine Hoof ◽  
The Relationship

An engineering fracture mechanics approach was applied to the analysis of the fracture resistance of equine hoof-wall. The relationship between fracture toughness and the morphological organization of the keratin hoof tissue was investigated. Fracture toughness was evaluated using the J-integral analysis method which employs the compact tension test geometry. Tensile tests were also conducted to evaluate the effect of the morphological organization on the stress-strain behaviour. Hoof-wall has greatest fracture resistance for cracks running proximally, parallel to the tubular component of the wall keratin. For fully hydrated material tested in this direction the mean critical J-integral value at failure was 1.19 X 10(4)J m-2. This was nearly three times greater than the value determined for the weakest orientation, in which the crack ran parallel to the material between the tubules. The lower fracture toughness of the intertubular material dominates the fracture behaviour of this tissue. The tubular components of the wall appear to reinforce against fracture along the weak plane and the entire wall organization provides the mechanical capability for limiting and controlling fracture in this tissue.

OS0621 Specimen size effect to the relationship between fracture toughness and critical stretched zone width in cold-worked SUS304

2008 ◽  
Vol 2008 (0) ◽  
pp. _OS0621-1_-_OS0621-2_
Author(s):  
Tadahiko Torimaru ◽  
Masanari Sugiyama ◽  
Hiroshi Sakamoto ◽  
Shigeaki Tanaka ◽  
Tomomi Nakamura
Keyword(s):  
Fracture Toughness ◽  
Size Effect ◽  
Specimen Size ◽  
Zone Width ◽  
Cold Worked ◽  
The Relationship

Burst Pressure Prediction of Cracked Steam Generator Tube Using FE Damage Analysis

2015 ◽  
Author(s):  
Jun-Young Jeon ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim
Keyword(s):  
Crack Propagation ◽  
Steam Generator ◽  
Test Data ◽  
Damage Model ◽  
Fe Analysis ◽  
Multiple Cracks ◽  
Outer Diameter ◽  
Damage Analysis ◽  
Element Size ◽  
Alloy 690

This paper predicts burst pressures of the steam generator tubes with multiple cracks using finite element (FE) damage analysis. Alloy 690(TT) tube (the outer diameter of 19.05 mm and the thickness of 1.07 mm) widely used in the nuclear power plant is considered in this study. Ductile failure at each element is predicted with the damage model known as ‘multi-axial fracture strain model’ as well as crack propagation is simulated by stress reduction technique in the FE analysis. Simplified ductile damage model for Alloy 690(TT) are determined using tube tensile test data and elastic-plastic FE analysis. FE damage analysis results are sensitive to the element size used in the crack propagation region. Using notched tube fracture test data, proper element size for Alloy 690(TT) is found. Single, collinear, parallel, non-aligned axial-cracks are considered in the simulations and the predicted burst pressures are compared with burst test data.

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