Pipe Sleeve Repair Analysis Case Study Examining Axial Surface Cracks With Pressure Reduction and Geometry Factors to Improve Remaining Life

2021 ◽  
Author(s):  
Greg Thorwald ◽  
Carolyn Kolovich
Keyword(s):  
Pressure Reduction ◽  
Surface Cracks ◽  
Remaining Life ◽  
Axial Surface

scholarly journals Risk analysis of gas leakage in gas pressure reduction station and its consequences: A case study for Zahedan

Heliyon ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. e06911
Author(s):  
Peiman Dadkani ◽  
Esmatullah Noorzai ◽  
AmirHossein Ghanbari ◽  
Ali Gharib
Keyword(s):  
Risk Analysis ◽  
Gas Pressure ◽  
Pressure Reduction ◽  
Gas Leakage ◽  
Pressure Reduction Station

scholarly journals A DAMAGE PROGNOSIS METHODOLOGY FOR A SIMPLE CRACKED BEAM

2018 ◽  
Vol 48 (1) ◽  
pp. 43-49
Author(s):  
E. A. PRESEZNIAK ◽  
J. E. PEREZ IPIÑA ◽  
C. A. BAVASTRI
Keyword(s):  
Fracture Mechanics ◽  
Nonlinear Optimization ◽  
Optimization Techniques ◽  
Crack Identification ◽  
Remaining Life ◽  
Damage Prognosis ◽  
Mechanics Concepts ◽  
Dynamic Structures ◽  
High Level

Damage prognosis uses numerical and experimental responses to identify damage in structures or part of them, thus allowing the remaining structural life estimation at a high level of precision. Current methods focalize on crack identification; however, a complete methodology to estimate the remaining life of a cracked structure is less developed. A methodology is presented in this paper drawing on concepts such as wavelets transform, dynamic structures, and vibration signals for crack identification; and fracture mechanics and nonlinear optimization to obtain the remaining life. Finite element theory was applied to obtain its vibration modes. The crack was modeled as a flexural spring connected to the elements in the crack position and the crack identification was performed in the wavelet domain. Nonlinear optimization techniques and fracture mechanics concepts were used to estimate the remaining fatigue life. A numerical-experimental case study is solved to show the fundamentals of this methodology.

Verification of the Combination Rules of Multiple Flaws in ASME B&PV Code Section XI: A Case Study of Two Adjacent Surface Planar Flaws

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Toshihisa Nishioka ◽  
Guangqin Zhou ◽  
Takehiro Fujimoto
Keyword(s):  
Finite Element ◽  
Cost Effective ◽  
Pressure Vessels ◽  
Surface Cracks ◽  
Combination Rule ◽  
Combination Rules ◽  
Alternating Method ◽  
Vna Solution ◽  
Coplanar Cracks

In nuclear pressure vessels, multiple surface cracks are often found by regular inspection. In order to evaluate the integrity of the vessels, ASME B&PV Code Section XI provides the flaw combination rules; however, its accuracy has not been clarified yet. For the analyses of interacting multiple semi-elliptical surface cracks, in 1983 Nishioka and Atluri developed the Vijayakumar, Nishioka, and Atluri (VNA) solution-finite element alternating method which is highly accurate and cost effective. Using this highly accurate VNA-finite element alternating method, the case of extremely closely located two interacting coplanar cracks was analyzed. From the numerical results, it is found that the B&PV Code Section XI provides a conservative flaw combination rule. Therefore, the B&PV Code Section XI is precisely verified by modern and accurate computational technologies.

Bulging Factor for Axial Surface Cracks in Pipes

2014 ◽  
Author(s):  
Do-Jun Shim ◽  
Gery Wilkowski
Keyword(s):  
Surface Crack ◽  
Maximum Pressure ◽  
Surface Cracks ◽  
Correction Factors ◽  
Constant Depth ◽  
Dugdale Model ◽  
Crack Driving Force ◽  
Actual Surface ◽  
Secant Equation ◽  
Axial Surface

The bulging factor for an external constant-depth axial surface crack in a pipe was calculated by 3D FE simulations. This was done in a manner consistent with Folias’s original work for the axial through-wall-cracked pipe bulging factor (MT), but was evaluated in the elastic to full-plastic conditions. The results demonstrated that the actual surface-cracked pipe bulging factor is considerably lower than the bulging factor empirically derived by Maxey/Kiefner (Mp) back in the 1970s. Based on the results of the present study, it is suggested that Mp function in the Ln-Secant equation is not truly a bulging factor for axial surface crack. Rather it is an empirically developed equation with many correction factors embedded in it to apply the Dugdale model for prediction of maximum pressure of axial surface-cracked pipes. However, due to this empiricism, this method becomes invalid (or overly conservative) when it is applied in predicting the crack-driving force using the J-based Ln-Secant equation.

Case Study: Non-Conventional Remaining Life Assessment of a Significant Dent in a Subsea Pipeline Scheduled for Decommissioning

2019 ◽  
Author(s):  
A. Brett ◽  
A. Russell
Keyword(s):  
Life Assessment ◽  
Remaining Life ◽  
Element Analysis ◽  
Oil Pipeline ◽  
The North ◽  
Pressure Spike ◽  
The North Sea ◽  
Specific Assessment ◽  
Remaining Life Assessment

Abstract An inline inspection of a subsea oil pipeline located in the North Sea identified a large top of line dent. The pipeline was scheduled for decommissioning within 3 years, however conventional fatigue assessment of the dent indicated that the pipeline could become unsafe before the scheduled decommissioning date. As the required remaining life could not be justified by conventional assessment, a review was completed to determine whether a case-specific assessment methodology could be developed to reduce the conservatism, while reliably demonstrating that the pipeline could be safely operated up until the planned decommissioning date. This review identified that the pipeline had a unique pressure history, which included a large one-off pressure spike that had occurred following detection of the dent. This raised the possibility of a pseudo-hydrotest type assessment to justify the required remaining life. This paper describes the non-conventional pseudo-hydrotest assessment that was undertaken for the dent to demonstrate acceptability, which used a combination of state of the art finite element analysis and fatigue crack growth assessment.

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