Advanced Finite Element Analysis (AFEA) Evaluation for Circumferential and Axial PWSCC Defects

2010 ◽  
Author(s):  
D.-J. Shim ◽  
S. Kalyanam ◽  
E. Punch ◽  
T. Zhang ◽  
F. Brust ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Growth ◽  
Crack Front ◽  
Nodal Point ◽  
Nuclear Industry ◽  
Element Analysis ◽  
Weld Residual Stress ◽  
Axial Crack

The Advanced Finite Element Analysis (AFEA) methodology has been developed by the US NRC and the nuclear industry to evaluate the natural crack growth of primary water stress corrosion cracking (PWSCC) in nickel-based alloy materials. The AFEA methodology allows the progression of a planar crack subjected to typical SCC-type growth laws by calculating stress intensity factors at every nodal point along the crack front, and incrementally advancing the crack front in a more natural manner. This paper describes the enhancements that have been made to the existing AFEA methodology. The most significant enhancement was the feature to evaluate axial crack growth where the crack was contained within the susceptible material. In this paper, this methodology was validated by performing an AFEA evaluation for the axial crack that was found in the V.C. Summer hot leg dissimilar metal weld. Other enhancements to the AFEA methodology include; upgrade to the PipeFracCAE© software developed by Engineering Mechanics Corporation of Columbus, feature to handle non-idealized circumferential through-wall cracks, mapping of weld residual stress for crack growth, and determination of limiting crack size using elastic-plastic J-integral analysis that included secondary stress (weld residual stress and thermal transient stress) effects.

Natural Crack Growth Analyses for Circumferential and Axial PWSCC Defects in Dissimilar Metal Welds

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Do-Jun Shim ◽  
Sureshkumar Kalyanam ◽  
Frederick Brust ◽  
Gery Wilkowski ◽  
Mike Smith ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Crack Front ◽  
Corrosion Cracking ◽  
Nuclear Industry ◽  
Dissimilar Metal ◽  
Weld Residual Stress ◽  
Axial Crack

The natural crack growth analysis (sometimes referred to as advanced finite element analysis (AFEA)) methodology has been developed by the US NRC and the nuclear industry to evaluate the natural crack growth due to primary water stress corrosion cracking (PWSCC) in nickel-based alloy materials. The natural crack growth (or AFEA) methodology allows the progression of a planar crack subjected to typical stress corrosion cracking (SCC)-type growth laws by calculating stress intensity factors at every nodal point along the crack front and incrementally advancing the crack front in a more natural manner. This paper describes the step-by-step procedure enhancements that have been made to the existing AFEA methodology. A significant enhancement was the feature to evaluate axial crack growth, where the crack was contained within the susceptible material. This methodology was validated by performing an AFEA evaluation for the axial crack that was found in the V.C. Summer hot-leg dissimilar metal weld (DMW). Other enhancements to the AFEA methodology include: feature to handle nonidealized circumferential through-wall cracks, mapping of weld residual stress for crack growth, and determination of limiting crack size using elastic-plastic J-integral analysis that included secondary stress (weld residual stress and thermal transient stress) effects.

Estimation of Stress Corrosion Cracking Growth Behavior Under Weld Residual Stress in the Bottom of a Reactor Pressure Vessel by Finite Element Analysis

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki ◽  
Masahito Mochizuki
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Growth Behavior ◽  
Element Analysis ◽  
Weld Residual Stress ◽  
Code Procedure ◽  
Reactor Pressure

A method for evaluating crack growth by repeatedly modeling and analyzing the transitional crack shapes is developed for a general computing environment in which a commercial finite element preprocessor and analysis code are used. The proposed method calculates stress intensity factors (SIFs) by finite element analysis (FEA) by directly distributing estimated weld residual stress obtained from noncracked components on the crack surface on the basis of the superposition principle. In present case, to specify a nonuniform residual stress distribution, a subroutine for a commercial FEA code (ABAQUS) was developed. Arbitrary crack shapes during the crack propagation were expressed by applying the submodeling technique which allowed arbitrary crack shapes to be meshed. The sequence of steps in the proposed method was designed to make it possible to consider complicated stress distributions, such as weld residual stress, and to express arbitrary crack shapes. The applicability of the proposed FEA based method was verified by comparing the result of a stress corrosion cracking (SCC) growth analysis results of a flat plate obtained with the proposed method and with the ASME code procedure. As an application example, the SCC growth behavior of a crack at the bottom of a nuclear reactor pressure vessel (RPV) involving a dissimilar metal weld and a unique geometry was evaluated by the proposed method. The evaluation results were compared with results obtained using a conventional method, i.e., the influence function method (IFM). Since both sets of results were in reasonable agreement, it was concluded that IFM can be applied to this case. Previously, it was difficult to assess the applicability of conventional methods, such as the code procedure and IFM, to a complicated problem because of the existence of complicated residual stress fields, dissimilar metals, and the complicated crack shapes involved. The proposed method using FEA allows the applicability of conventional methods to complicated crack growth evaluations to be assessed.

Estimation of SCC Crack Growth Behavior Under Weld Residual Stress in the Bottom of a Reactor Pressure Vessel by Finite Element Analysis

2012 ◽  
Author(s):  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki ◽  
Masahito Mochizuki
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Crack Growth ◽  
Influence Function ◽  
Function Method ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Element Analysis ◽  
Influence Function Method ◽  
Weld Residual Stress

Crack growth behavior intended for stress corrosion cracking under residual stress was estimated by repeatedly calculated 3-dimensional finite element analysis. The analytical estimation enables consideration of complicated stress distributions, such as weld residual stress, and expression of arbitrary crack shapes. Estimated weld residual stress for non-cracked components was distributed on the crack surface on the basis of superposition principle in order to calculate stress intensity factors. Specifically, the user subroutine DLOAD to specify a non-uniformly distribution load in ABAQUS was applied in the finite element analysis. Arbitrary crack shapes due to the crack propagation were expressed by applying the sub-modeling. The sub-modeling facilitated automatic modeling of cracked components. The estimation results intended for a SCC crack in the bottom of the reactor pressure vessel expressed the complicated crack growth shape along the weld metal. Moreover, crack growth behavior was estimated using the influence function method. The influence function method assumes arbitrary stress distribution and semi-elliptical crack shapes. Applicability of the influence function method was confirmed by comparisons with FEA results.

Online Software Tool for Predicting Weld Residual Stress and Distortion

2008 ◽  
Author(s):  
Yu-Ping Yang ◽  
Wei Zhang ◽  
Wei Gan ◽  
Shuchi Khurana ◽  
Junde Xu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
High Performance ◽  
Local Heating ◽  
Welding Parameters ◽  
Analysis Tool ◽  
Element Analysis ◽  
Weld Residual Stress ◽  
Welding Processes

Weld residual stress and distortion are inevitable during welding due to rapid local heating and cooling, high-temperature material reactions and weld-fixture effects. To predict weld residual stress and distortion, an engineer has to understand welding processes and the finite element analysis method. It is difficult for an engineer without finite element background to calculate the weld residual stress and distortion. With the development of weld modeling technology, automatic meshing generation, and high performance computation, a web-based analysis tool (E-Weld Predictor), was developed to predict weld residual stress and distortion. This allows an engineer to calculate the weld residual stress and distortion on line. The engineer does not need to have finite element analysis knowledge to perform the calculation. By providing welding parameters, defining a weld joint, giving geometry dimensions, and specifying a material, weld residual stress and distortion are automatically calculated in a remote high performance computer. A report will then be sent to the engineer to review. This paper introduces the development of E-Weld Predictor. The software structure, the theory, the implementation, and the validation of E-Weld Predictor are discussed in detail. It also shows the simulation process of applying this software in predicting temperature, microstructure, residual stress and distortion.

Use of an elasto-plastic model and strain measurements of embedded fibre Bragg grating sensors to detect Mode I delamination crack propagation in woven cloth (0/90) composite materials

2017 ◽  
Vol 17 (2) ◽  
pp. 363-378 ◽  
Author(s):  
Ayad Arab Kakei ◽  
Mainul Islam ◽  
Jinsong Leng ◽  
Jayantha A Epaarachchi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Front ◽  
Double Cantilever Beam ◽  
Bragg Grating ◽  
Mode I ◽  
Fibre Bragg Grating ◽  
Element Analysis ◽  
Plastic Model ◽  
Mode I Delamination

Mode I fracture analysis being employed to study delamination damage in fibre-reinforced composite structures under in-plane and out-of-plane load applications. However, due to the significantly low yield strength of the matrix material and the infinitesimal thickness of the interface matrix layer, the actual delamination process can be assumed as a partially plastic process (elasto-plastic). A simple elasto-plastic model based on the strain field in the vicinity of the crack front was developed for Mode I crack propagation. In this study, a double cantilever beam experiment has been performed to study the proposed process using a 0/90-glass woven cloth sample. A fibre Bragg grating sensor has embedded closer to the delamination to measure the strain at the vicinity of the crack front. Strain energy release rate was calculated according to ASTM D5528. The model predictions were comparable with the calculated values according to ASTM D5528. Subsequently, a finite element analysis on Abaqus was performed using ‘Cohesive Elements’ to study the proposed elasto-plastic behaviour. The finite element analysis results have shown a very good correlation with double cantilever beam experimental results, and therefore, it can be concluded that Mode I delamination process of an fibre-reinforced polymer composite can be monitored successfully using an integral approach of fibre Bragg grating sensors measurements and the prediction of a newly proposed elasto-plastic model for Mode I delamination process.

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