An extended finite element method-based representative model for primary water stress corrosion cracking of a control rod driving mechanism penetration nozzle

2017 ◽  
Vol 41 (1) ◽  
pp. 138-145
Author(s):  
H. Lee ◽  
S.J. Kang ◽  
J.B. Choi ◽  
M.K. Kim
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Water Stress ◽  
Stress Corrosion Cracking ◽  
Extended Finite Element Method ◽  
Driving Mechanism ◽  
Extended Finite Element ◽  
Control Rod ◽  
Primary Water ◽  
Representative Model

PWSCC Assessment by Using Extended Finite Element Method

2015 ◽  
Vol 06 (03) ◽  
pp. 1550007
Author(s):  
Sung-Jun Lee ◽  
Sang-Hwan Lee ◽  
Yoon-Suk Chang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Extended Finite Element Method ◽  
Structural Integrity ◽  
Displacement Function ◽  
Driving Mechanism ◽  
Extended Finite Element ◽  
Control Rod ◽  
Head Penetration ◽  
Element Method

The head penetration nozzle of control rod driving mechanism (CRDM) is known to be susceptible to primary water stress corrosion cracking (PWSCC) due to the welding-induced residual stress. Especially, the J-groove dissimilar metal weld regions have received many attentions in the previous studies. However, even though several advanced techniques such as weight function and finite element alternating methods have been introduced to predict the occurrence of PWSCC, there are still difficulties in respect of applicability and efficiency. In this study, the extended finite element method (XFEM), which allows convenient crack element modeling by enriching degree of freedom (DOF) with special displacement function, was employed to evaluate structural integrity of the CRDM head penetration nozzle. The resulting stress intensity factors of surface cracks were verified for the reliability of proposed method through the comparison with those suggested in the American Society of Mechanical Engineering (ASME) code. The detailed results from the FE analyses are fully discussed in the manuscript.

scholarly journals Effect of Material Macrostructural Parameters on Quantitative Stress Corrosion Cracking Plastic Zone Using Extended Finite Element Method in Welded Joints for Light Water Reactor Environment

CORROSION ◽  
10.5006/3498 ◽  
2020 ◽  
Vol 76 (9) ◽  
pp. 826-834
Author(s):  
Rehmat Bashir ◽  
He Xue ◽  
Jianlong Zhang ◽  
Rui Guo ◽  
Nasir Hayat ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Yield Strength ◽  
Plastic Zone ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Extended Finite Element Method ◽  
Alloy 600 ◽  
Extended Finite Element ◽  
Light Water

Alloy 600, a nickel-chromium alloy, has an outstanding corrosion resistance with excellent fabricability and is used in light water reactors at elevated temperatures. The alloy is also being considered for an advanced reactor concept because of its high allowable design strength at the elevated temperature. Alloy 600 is a power hardening material and basic plastic properties of the alloy are changed in the welded zone due to inhomogeneity in weld joints. The extended finite element method (XFEM) is used when the problem of variations invariably in the stress intensity factors (K) at a different instant rate exists. This paper focuses on the effect of variations in macrostructural properties of the alloy on stress corrosion cracking plastic zone ahead of the crack-tip using XFEM. To control the variations in the K, a new technique is also introduced in this research. The results show that the plastic zone is affected by K (increases with the increase of K), yield strength (plastic zone decreases with the increase in yield strength), and hardening exponent “n” (core region increases with the increase of exponent) of the materials. Simulations were performed and results are compared with experimental data.

scholarly journals A mesh-independent framework for crack tracking in elastodamaging materials through the regularized extended finite element method

2021 ◽  
Author(s):  
Elena Benvenuti ◽  
Nicola Orlando
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Damage Evolution ◽  
Extended Finite Element Method ◽  
Mesh Adaptivity ◽  
Extended Finite Element ◽  
Evolution Law ◽  
Crack Paths ◽  
Original Crack ◽  
Element Method

AbstractWe propose a formulation for tracking general crack paths in elastodamaging materials without mesh adaptivity and broadening of the damage band. The idea is to treat in a unified way both the damaging process and the development of displacement discontinuities by means of the regularized finite element method. With respect to previous authors’ contributions, a novel damage evolution law and an original crack tracking framework are proposed. We face the issue of mesh objectivity through several two-dimensional tests, obtaining smooth crack paths and reliable structural results.

scholarly journals An Extended Finite Element Method (XFEM) Study on the Elastic T-Stress Evaluations for a Notch in a Pipe Steel Exposed to Internal Pressure

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 507
Author(s):  
K. Yakoubi ◽  
S. Montassir ◽  
Hassane Moustabchir ◽  
A. Elkhalfi ◽  
Catalin Iulian Pruncu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Extended Finite Element Method ◽  
Research Study ◽  
Extended Finite Element ◽  
T Stress ◽  
Cracked Structures ◽  
Element Method

The work investigates the importance of the K-T approach in the modelling of pressure cracked structures. T-stress is the constant in the second term of the Williams expression; it is often negligible, but recent literature has shown that there are cases where T-stress plays the role of opening the crack, also T-stress improves elastic modeling at the point of crack. In this research study, the most important effects of the T-stress are collected and analyzed. A numerical analysis was carried out by the extended finite element method (X-FEM) to analyze T-stress in an arc with external notch under internal pressure. The different stress method (SDM) is employed to calculate T-stress. Moreover, the influence of the geometry of the notch on the biaxiality is also examined. The biaxiality gave us a view on the initiation of the crack. The results are extended with a comparison to previous literature to validate the promising investigations.

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