On the Stress Concentration in Multiple Notches

1962 ◽  
Vol 29 (3) ◽  
pp. 575-577 ◽  
Author(s):  
Kunio Nishioka ◽  
Nobuyoshi Hisamitsu
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Two Dimensional ◽  
Notch Depth ◽  
Pure Bending ◽  
Finite Plate ◽  
Photoelastic Investigation ◽  
Plate Width

The two-dimensional photoelastic investigation has been made on the effect of plate width, pitch, and depth of notch on the stress-concentration factor in a finite plate, which is for the single and multiple notches of any depth, under pure bending. Thus the stress-concentration factor, the effective notch depth, and the reduction of stress concentration caused by multiple notches were clarified.

The Flow and Fracture of a Brittle Material

1950 ◽  
Vol 17 (3) ◽  
pp. 233-248
Author(s):  
L. F. Coffin
Keyword(s):  
Cast Iron ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Gray Cast Iron ◽  
Gray Cast ◽  
Residual Tensile Stress ◽  
Two Dimensional ◽  
Combined Stress ◽  
Plastic Stress

Abstract The mechanism of flow and fracture of a gray cast iron can be understood if one considers the microstructure to consist of a ductile structure with a random dispersion of cracks due to the graphite flakes following the concept of Fisher. A notch effective stress can be calculated for a critically situated crack by a knowledge of the external stresses, a plastic stress-concentration factor of 3, and a residual tensile stress at the sharp edge of the crack, based upon either the “maximum-shear” theory or the “distortion-energy” theory. This allows the formulation of generalized plastic stress-strain relationships and renders gray cast iron applicable to the many known solutions for plastic flow of ductile metals. Fracture in the region of tension-tension and tension-compression can be evaluated by a similar analysis, using the same stress-concentration factor and the same residual stress. A combined stress-testing program is described wherein thin-walled cast-iron tubes are subjected to two-dimensional states of combined stress covering the complete two-dimensional field.

Stress Distribution Around Edge Slits in a Plate Loaded in Tension —the Effect of Finite Width of Plate

1962 ◽  
Vol 66 (617) ◽  
pp. 320-322 ◽  
Author(s):  
J. R. Dixon
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Flat Plate ◽  
Elastic Stress ◽  
Width Ratio ◽  
Finite Width ◽  
Two Dimensional ◽  
Finite Plate ◽  
Edge Slit ◽  
Plate Width

SummaryTwo-dimensional photoelastic tests have been carried out on uni-axially loaded flat-plate specimens with two collinear edge slits, to investigate the effect of finite plate width on the elastic stress distribution. It was found that the effect of slitlength/ plate-width ratio on the elastic stress concentration at the end of the edge slit of length l was virtually the same as that for a central slit of length 2l in a plate of the same width, and could be adequately expressed by existing theories.

A Design Equation for the Stress Concentration Factor of an Oblate Ellipsoidal Cavity

2011 ◽  
Vol 46 (2) ◽  
pp. 87-94 ◽  
Author(s):  
C-R Chiang
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Isotropic Material ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Ellipsoidal Cavity ◽  
Equivalent Inclusion Method ◽  
Equivalent Inclusion ◽  
Correction Terms

The stress concentration factor (SCF) of an oblate ellipsoidal cavity in an isotropic material subjected to a uniform normal stress at infinity perpendicular to the equator of the cavity is determined by the equivalent inclusion method. Numerical results are obtained for general cases; particularly, explicit and exact results are obtained for cases of strongly oblate cavities. To extend the range of validity for these cases, a two-dimensional model is developed for finding the correction terms and a simple equation for the SCF of an oblate ellipsoidal cavity is thus obtained. The accuracy of the equation is probed and it is shown that the proposed formula is sufficiently accurate for design purposes.

Extent of the Surface Region in Notched Middle Cracked Tension Specimens

2013 ◽  
Vol 560 ◽  
pp. 107-127 ◽  
Author(s):  
R. Branco ◽  
F.V. Antunes ◽  
J.D. Costa
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Elastic Stress ◽  
Stress Triaxiality ◽  
Surface Region ◽  
Notch Depth ◽  
Notch Radius ◽  
Growth Technique ◽  
Fully Automatic

This article aims at evaluating the extent of the surface region in notched Middle Cracked Tension specimens. Firstly, a fully automatic fatigue crack growth technique is developed to obtain stable crack shapes. After that, the stress triaxiality along the crack front is evaluated for different notch shapes. Then, objective criteria are defined to quantify the extent of the surface region from the stress triaxiality data collected. Next, the extent of the surface region is related to the elastic stress concentration factor of the uncracked geometry by a linear relationship. Finally, empirical two-constant equations able to evaluate the extent of the surface region from the thickness, notch radius, notch depth and elastic stress concentration factor are formulated.

Photoelastic Investigation on Plates with Single Interference-Fit Pins with Load Applied to Plate Only

1956 ◽  
Vol 7 (4) ◽  
pp. 297-314 ◽  
Author(s):  
H. T. Jessop ◽  
C. Snell ◽  
G. S. Holister
Keyword(s):  
Stress Concentration ◽  
Flat Plate ◽  
Circular Hole ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Hole Diameter ◽  
Interference Fit ◽  
Applied Tension ◽  
Photoelastic Investigation ◽  
Hole Boundary

SummaryThe introduction of an interference-fit pin in a circular hole in a flat plate is found to result in a reduction in the stress concentration factor at the hole boundary under tension applied to the plate. The S.C.F. decreases rapidly with increase in the ratio of interference stress to applied tension, and decreases also with increase in the ratio of hole diameter to width of plate. Very little difference in the S.C.F. is found for different ratios of Young's modulus of pin and plate.

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.

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