A novel correlation to calculate stress intensity factors of the semi-elliptical crack in high-strength carbon steel pipe based on extended isogeometric analysis

2022 ◽  
Vol 44 (1) ◽  
Author(s):  
Ata Fardaghaie ◽  
Shahram Shahrooi ◽  
Mohammad Shishehsaz
Keyword(s):  
Stress Intensity ◽  
Carbon Steel ◽  
Stress Intensity Factors ◽  
Isogeometric Analysis ◽  
High Strength ◽  
Elliptical Crack ◽  
Steel Pipe ◽  
Intensity Factors

scholarly journals Effects of Corrosion on Mechanical Properties of Welded Carbon Steel Pipe in District Heating Water

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3682 ◽  
Author(s):  
Sang-Jin Ko ◽  
Jeong-Hun An ◽  
Yong-Sang Kim ◽  
Woo-Cheol Kim ◽  
Jung-Gu Kim
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity ◽  
Carbon Steel ◽  
Aging Time ◽  
Stress Intensity Factors ◽  
District Heating ◽  
Tensile Tests ◽  
Steel Pipe ◽  
Intensity Factors ◽  
Heating Water

This study examined the effect of corrosion on mechanical properties of welded carbon steel pipe in district heating water. To evaluate the corrosion properties, potentiodynamic tests were conducted and a galvanostatic test was used to accelerate corrosion. Tensile tests and microstructure observations were performed to figure out the degradation of the corroded region, and stress intensity factors were calculated. As a result of the potentiodynamic tests, welded carbon steel pipe showed uniform corrosion and the total charge was calculated. Using the galvanostatic test, the current density at the equivalent aging time was applied to the specimens. The tensile tests showed that according to corrosion damages, mechanical properties were degraded due to corrosion. Through the microstructure observations and calculations of stress intensity factors, the corrosion of the welded carbon steel pipe induced the degradation of mechanical properties. The mode of fracture was changed from ductile to brittle fracture with increasing aging time.

scholarly journals Influence Coefficients to Calculate Stress Intensity Factors for an Elliptical Crack in a Plate

2002 ◽  
Author(s):  
Patrick Le Delliou ◽  
Bruno Barthelet
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Atomic Energy Commission ◽  
Finite Thickness ◽  
Elliptical Crack ◽  
Intensity Factors ◽  
Normal Loading ◽  
Influence Coefficients ◽  
Wide Range

Crack assessment in engineering structures relies first on accurate evaluation of the stress intensity factors. In recent years, a large work has been conducted in France by the Atomic Energy Commission to develop influence coefficients for surface cracks in pipes. However, the problem of embedded cracks in plates (and pipes) which is also of practical importance has not received so much attention. Presently, solutions for elliptical cracks are available either in infinite solid with a polynomial distribution of normal loading or in plate, but restricted to constant or linearly varying tension. This paper presents the work conducted at EDF R&D to obtain influence coefficients for plates containing an elliptical crack with a wide range of the parameters: relative size (2a/t ratio), shape (a/c ratio) and crack eccentricity (2e/t ratio where e is the distance from the center of the ellipse to the plate mid plane). These coefficients were developed through extensive 3D finite element calculations: 200 geometrical configurations were modeled, each containing from 18000 to 26000 nodes. The limiting case of the tunnel crack (a/c = 0) was also analyzed with 2D finite element calculation (50 geometrical configurations). The accuracy of the results was checked by comparison with analytical solutions for infinite solids and, when possible, with solutions for finite-thickness plates (generally loaded in constant tension). These solutions will be introduced in the RSE-M Code that provides rules and requirements for in-service inspection of French PWR components.

scholarly journals Weight Function Approach for Semi Elliptical Crack at Blade Mounting Locations in Steam Turbine Rotor System

2018 ◽  
Vol 62 (3) ◽  
pp. 203-208
Author(s):  
Damarla Kiran Prasad ◽  
Kavuluri Venkata Ramana ◽  
Nalluri Mohan Rao
Keyword(s):  
Stress Intensity ◽  
Weight Function ◽  
Steam Turbine ◽  
Stress Intensity Factors ◽  
Turbine Rotor ◽  
Rotor System ◽  
Elliptical Crack ◽  
Influence Coefficient ◽  
Intensity Factors ◽  
Steam Turbine Rotor

This paper presents analysis of stress intensity factors at blade mounting locations of steam turbine rotor system. General expressions for the stresses induced in a rotating disc are derived and these equations are applied to steam turbine rotor disc. It is observed that the radial stress increases instantly at blade mounting location which indicates the probability of crack initiation and growth. A semi elliptical crack is considered at that location and weight function approach is used to determine the stress intensity factors. The results are validated with the influence coefficient approach. The differences of present approach with influence coefficient approach are less than 3 %. Hence the present approach is suitable for determination of stress intensity factors in a semi elliptical crack at blade mounting locations of a steam turbine rotor disc.

Influence Coefficients of Stress Intensity Factors for Curved Tubing With a Semi-Elliptical Crack

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Kirsten Plante ◽  
Choon-Lai Tan
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Crack Depth ◽  
Elliptical Crack ◽  
Radius Ratio ◽  
Intensity Factors ◽  
Cross Sectional ◽  
Influence Coefficients ◽  
Wide Range ◽  
Angular Extent

The boundary element method is employed to determine polynomial influence coefficients of stress intensity factors, KI, for a semi-elliptical crack in internally pressurized thick-walled curved tubing. Numerical results of these coefficients are obtained for a wide range of geometric parameters; they are the bend radius ratio, cross-sectional radius ratio, angular extent of the bend, and relative crack depth. The use of influence coefficients allows KI solutions to be determined for different load cases without repetitive 3D stress analysis of the cracked body. This is demonstrated for the case of autofrettage where the effects on KI of the residual stresses arising from it are presented.

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