Numerical investigation on torsional stress concentration factor at the semi elliptical corrosion pit

2013 ◽  
Vol 67 ◽  
pp. 225-232 ◽  
Author(s):  
Muhammet Cerit
Keyword(s):  
Stress Concentration ◽  
Numerical Investigation ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Torsional Stress ◽  
Corrosion Pit

Torsional Stress Concentration Factors for Grooved Shafts

1967 ◽  
Vol 71 (673) ◽  
pp. 40-43 ◽  
Author(s):  
K. R. Rushton
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Preliminary Investigation ◽  
Approximate Expression ◽  
Data Sheet ◽  
Analogue Computer ◽  
Torsional Stress ◽  
Concentration Factors ◽  
Stress Concentration Factors

SummaryThis paper describes a preliminary investigation of the torsional stress concentration factors for circular shafts containing grooves determined using an analogue computer. The range covered by this analysis is for grooves which increase in depth from a minimum of 0·05 of the diameter of the shaft, with radii which vary from 0·5 to 0·05 of the diameter at the minimum section. Results are presented in the form of a data sheet, and a comparison is made with the approximate expression of Neuber. An investigation is also made of the modifications to the stress concentration factor if the flank is not perpendicular to the centre-line of the shaft.

Correlation between the Geometric Parameters of Corrosion Pit and Stress Concentration Factor

2013 ◽  
Vol 327 ◽  
pp. 156-160 ◽  
Author(s):  
Wei Zhao ◽  
Yong Fang Huang ◽  
Xu Bin Ye ◽  
Ben Run Hu ◽  
Jian Zhong Liu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Three Dimensional ◽  
Optical Microscope ◽  
Quantitative Relation ◽  
Estimation Formula ◽  
Corrosion Pit ◽  
Stress Concentration Effect

Corrosion is one major damage mechanisms of aircraft structure, which can result in catastrophic failures and disasters. Quantitative analysis of pitting stress concentration effect is necessary for aircraft aluminum alloy structures, especially in coastal area. In the present paper, based on the observations of corrosion pit morphology of 2524 aluminum alloy using Keyence VHX-600 optical microscope and white light confocal microscope, three-dimensional finite element analyses (FEA) had been conducted systematically to evaluate the stress distribution of the cuboids aluminum alloy specimen with pits stressed remotely under uniaxial tension. It is found that pit metric parameter a/2c is the key parameter affecting stress concentration factor (SCF) and an empirical quantitative relation is given. In addition, we study the contribution of secondary (premature) pits at the bottom of hemi-spherical pit to the SCF of primary pit and an estimation formula is given. These provide significant methods for characterizing pitting damage and quantitatively estimating SCF so as to predict life.

scholarly journals A novel thread connection structure of slimehole drilling tool in ultra-deep natural gas well

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110264
Author(s):  
Zhang Ying ◽  
Lian Zhanghua ◽  
Gao Anqi ◽  
Yang Kun
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Sensitivity Coefficient ◽  
Notch Sensitivity ◽  
Sensitivity Factor ◽  
Drilling Tool ◽  
Gas Well ◽  
Thread Connection

The thread connection’s root fillet radius of 0.038″ size is the greatest weakness of the API NC type joints and thread. During the slimehole drilling, especially in the deep and ultra-deep gas well, its stress concentration factor and notch sensitivity factor are very high A novel thread connection design (TM) of a drilling tool is proposed to decrease the fatigue failure of the slimehole drilling tool in the deep and the ultra-deep gas well in the Tarim oilfield China. The novelty in the TM thread structure is, reducing the threads per inch, extending the distance from the last engaged thread to the external shoulder of the pin and adding three threads to the conventional connection. The novel thread connection will improve the slimehole drilling tool’s anti-fatigue life due to its improved elasticity and rigidity. Furthermore, the TM can transfer the maximum stress at the connection root to the loaded surface, which can effectively lower the fatigue notch’s sensitivity coefficient. In this paper, the finite element method (FEM) is applied to carry out the detailed comparative analysis of the TM with existing thread connection NC38, TX60 and TH90. The TM has the lowest stress concentration factor and fatigue notch sensitivity coefficient, so its anti-fatigue life is the highest. In addition, TM is manufactured and is tested at Tarim oilfield in China.

Stress Concentration of Periodic Collinear Square Holes in an Infinite Plate in Tension

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Changqing Miao ◽  
Yintao Wei ◽  
Xiangqiao Yan
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Infinite Plate ◽  
Numerical Approach ◽  
Numerical Examples ◽  
Calculated Stress ◽  
Bueckner’S Principle

A numerical approach for the stress concentration of periodic collinear holes in an infinite plate in tension is presented. It involves the fictitious stress method and a generalization of Bueckner's principle. Numerical examples are concluded to show that the numerical approach is very efficient and accurate for analyzing the stress concentration of periodic collinear holes in an infinite plate in tension. The stress concentration of periodic collinear square holes in an infinite plate in tension is studied in detail by using the numerical approach. The calculated stress concentration factor is proven to be accurate.

Fracture of Inoculated Iron Under Biaxial Stresses

1955 ◽  
Vol 22 (2) ◽  
pp. 172-174
Author(s):  
I. Cornet ◽  
R. C. Grassi
Keyword(s):  
Cast Iron ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Gray Cast Iron ◽  
Energy Criterion ◽  
Gray Cast ◽  
Published Data ◽  
Thin Wall ◽  
As Stress

Abstract Data are presented on the fracture of inoculated-iron thin-wall tubes, investigated under various ratios of axial to tangential stress, ranging from pure tension to pure compression. These data are consistent with published data on gray cast iron. It may be assumed that in cast-iron, plates of friable graphite in an iron matrix, act like solid iron with respect to compressive stresses, but they act as stress-concentrating cavities with respect to tensile stresses. This gives a stress-concentration factor, which is easily determined experimentally. Stress-concentration factors obtained were 3.2–3.3 for gray cast iron, and 2.4–2.5 for inoculated cast iron. A distortion-energy criterion for fracture, modified by this stress-concentration factor, is consistent with the experimental data. It appears that the concentration of the dispersed graphite, and the shape and size of this brittle phase, affect the fracture strength under combined stresses.

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