Assessing Soil Residual Stresses and Their Impact on Cracking Behavior

2007 ◽  
Author(s):  
Majdi R Abou Najm ◽  
Rabi H Mohtar ◽  
Jason W Weiss ◽  
Erik Braudeau
Keyword(s):  
Residual Stresses ◽  
Cracking Behavior

scholarly journals Prediction of Reheat Cracking Behavior in a Service Exposed 316H Steam Header

2020 ◽  
pp. 2050009
Author(s):  
Haoliang Zhou ◽  
Ali Mehmanparast ◽  
Kamran Nikbin
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Early Stage ◽  
Creep Crack Growth ◽  
Cracking Behavior ◽  
Displacement Boundary ◽  
Root Cause ◽  
Reheat Cracking ◽  
Weld Toe ◽  
Steam Header

Reheat cracking in an ex-service Type 316H stainless steel steam header component has been investigated in this study. The examined steam header was in service for 87,790[Formula: see text]h and the cracks in this component were found in the vicinity of the weld toe. The root cause of this type of failure was due to the welding residual stresses. The welding-induced residual stresses had been present in the header at the early stage of the operation and were released during service. In this paper, a novel technique has been proposed to simulate the residual stress distribution normal to the crack direction by applying remote fixed displacement boundary conditions in an axisymmetric model. This approach can simulate the presence of residual stresses in actual components without the need to develop full weld simulation to quantify them. The predicted residual stress levels and distributions normal to the crack direction have been found in good agreement with the measured residual stresses available in the literature for a similar header. The creep crack growth (CCG) rates have been characterized using the fracture mechanics [Formula: see text] parameter and estimated using predictive models.

Uncertainty Sampling of Weld Residual Stress Fields in Probabilistic Analysis: Part II — Examples

2016 ◽  
Author(s):  
Robert E. Kurth ◽  
Cédric J. Sallaberry ◽  
Frederick W. Brust ◽  
Elizabeth A. Kurth ◽  
Michael L. Benson ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Residual Stresses ◽  
Assessment Tool ◽  
Lessons Learned ◽  
Piping System ◽  
Primary System ◽  
Cracking Behavior ◽  
System Pressure ◽  
Piping Systems ◽  
Low Probability

NRC Standard Review Plan (SRP) 3.6.3 describes Leak-Before-Break (LBB) assessment procedures that can be used to assess compliance with the 10CFR50 Appendix A, GDC-4 requirement that primary system pressure piping exhibit an extremely low probability of rupture. SRP 3.6.3 does not allow for assessment of piping systems with active degradation mechanisms, such as Primary Water Stress Corrosion Cracking (PWSCC) which is currently occurring in systems that have been granted LBB approvals. US NRC staff, working cooperatively with the Electric Power Research Institute through a memorandum of understanding, conducted a multi-year project that focused on the development of a viable method and approach to address the effects of PWSCC in primary piping systems approved for LBB. This project, called eXtremely Low Probability of Rupture (xLPR) [1], defined the requirements necessary for a modular-based probabilistic fracture mechanics assessment tool to directly assess compliance with the regulations. Using the lessons learned from the pilot study, the production version of this code, designated as Version 2.0, focused on those primary piping systems previously approved for LBB. In this version the appropriate fracture mechanics-based models are employed to model the physical cracking behavior and a variety of computational options are provided to characterize, categorize and propagate problem uncertainties. One of the most influential uncertainty on risk in the xLPR code is the one associated with weld residual stresses (WRS). WRS plays a key role in both crack initiation and crack growth. PWSCC is mainly driven by tensile stresses, whose major contributors are the tensile weld residual stresses that develop during fabrication of the piping system. Handling the uncertainty involved with WRS within a probabilistic framework is quite challenging. A companion paper presents the selected approach to represent uncertainty within the framework of the xLPR code while respecting a set of requirements in term of smoothness of profile, efficiency of (potential) importance sampling and (for axial WRS) equilibrium. This paper illustrate with examples the implementation of the described methods into xLPR v2.0.

CrN/AlN nanolaminates: Architecture, residual stresses, and cracking behavior

2022 ◽  
Vol 40 (1) ◽  
pp. 013414
Author(s):  
K. Bobzin ◽  
T. Brögelmann ◽  
N. C. Kruppe ◽  
H. J. Maier ◽  
T. Heidenblut ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Cracking Behavior

Uncertainty Sampling of Weld Residual Stress Fields in Probabilistic Analysis: Part I — Theory

2016 ◽  
Author(s):  
Robert E. Kurth ◽  
Cédric J. Sallaberry ◽  
Frederick W. Brust ◽  
Elizabeth A. Kurth ◽  
Michael L. Benson ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Residual Stresses ◽  
Assessment Tool ◽  
Lessons Learned ◽  
Piping System ◽  
Primary System ◽  
Cracking Behavior ◽  
System Pressure ◽  
Piping Systems ◽  
Low Probability

NRC Standard Review Plan (SRP) 3.6.3 describes Leak-Before-Break (LBB) assessment procedures that can be used to assess compliance with the 10CFR50 Appendix A, GDC-4 requirement that primary system pressure piping exhibit an extremely low probability of rupture. SRP 3.6.3 does not allow for assessment of piping systems with active degradation mechanisms, such as Primary Water Stress Corrosion Cracking (PWSCC) which is currently occurring in systems that have been granted LBB approvals. US NRC staff, working cooperatively with the Electric Power Research Institute through a memorandum of understanding, conducted a multi-year project that focused on the development of a viable method and approach to address the effects of PWSCC in primary piping systems approved for LBB. This project, called eXtremely Low Probability of Rupture (xLPR), defined the requirements necessary for a modular-based probabilistic fracture mechanics assessment tool to directly assess compliance with the regulations [1]. Using the lessons learned from the pilot study [2] the production version of this code, designated as Version 2.0, focused on those primary piping systems previously approved for LBB [3]. In this version the appropriate fracture mechanics-based models are employed to model the physical cracking behavior and a variety of computational options are provided to characterize, categorize and propagate problem uncertainties. One of the most influential sources of uncertainty on risk in the xLPR code is the one associated with weld residual stresses (WRS). WRS plays a key role in both crack initiation and crack growth. PWSCC is mainly driven by tensile stresses, whose major contributors are the tensile weld residual stresses that develop during fabrication of the piping system. Handling the uncertainty involved with WRS within a probabilistic framework is quite challenging. This paper presents the selected approach to represent uncertainty within the framework of the xLPR code while respecting a set of requirements in term of smoothness of profile, efficiency of (potential) importance sampling and (for axial WRS) equilibrium. The current WRS sampling scheme employs correlation in order to smooth the shape of the WRS fields through the thickness of a dissimilar metal weld. This method presents an enrichment of the Cholesky decomposition on the correlation matrix, in order to satisfy the other two requirements.

Method to evaluate residual stresses in the laser cutting process

2002 ◽  
Vol 12 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Y. Zamachtchikov ◽  
F. Breaban ◽  
P. Vantomme ◽  
A. Deffontaine
Keyword(s):  
Residual Stresses ◽  
Laser Cutting ◽  
Cutting Process

Prediction of residual stresses and springback after bending of a textured aluminium plate

2003 ◽  
Vol 105 ◽  
pp. 175-182 ◽  
Author(s):  
L. Delannay ◽  
R. E. Logé ◽  
Y. Chastel ◽  
P. Van Houtte
Keyword(s):  
Residual Stresses

Theoretical study of the prestressing strand's stress by computer modeling methods

2020 ◽  
Vol 76 (11) ◽  
pp. 1139-1148
Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik
Keyword(s):  
Residual Stresses ◽  
High Strength ◽  
Pearlitic Steel ◽  
Internal Stresses ◽  
Steel Microstructure ◽  
Compressive Stresses ◽  
Wide Range ◽  
Prestressing Strands ◽  
Increasing Temperature ◽  
Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

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