A Factorial Design Approach to Investigate the Effect of Geometry in Drill String Screw Connectors

1995 ◽  
Vol 117 (2) ◽  
pp. 101-107 ◽  
Author(s):  
H. Bahai ◽  
I. I. Esat ◽  
L. Rass
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Factorial Design ◽  
Stress Concentration Factor ◽  
Parametric Study ◽  
Design Method ◽  
Drill String ◽  
Parametric Equation ◽  
Efficient Calculation ◽  
Bending Modes

This paper describes a parametric study of drill string threaded connector design based on a “factorial design” method. The study is facilitated by a hybrid model which has been developed, validated, and reported previously, enabling efficient calculation of load and stress distribution along threaded connectors subjected to both axial and bending modes of loading. A parametric equation is produced where stress concentration factor is defined in terms of various geometrical variables. The equation is then utilized to carry out a constrained optimization within the feasible parameter space, and hence produce an “optimum” thread and connector design.

A Reconsideration of the Geometry Factor for the Standard and Profile Shifted Teeth

1989 ◽  
Vol 111 (3) ◽  
pp. 402-413 ◽  
Author(s):  
J. H. Kuang ◽  
Y. T. Yang
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Concentration Factor ◽  
Empirical Equation ◽  
Design Parameters ◽  
Spur Gears ◽  
Geometry Factor ◽  
Gear Teeth ◽  
Semi Empirical

A semi-empirical equation for the determination of the stress concentration factor for spur gears is introduced. The effects of some design parameters such as fillet radii of rack cutters, teeth number, and profile shifting factor, on the stress distribution at the fillets of gear teeth are investigated. Values of the modified geometry factors for the standard and profile shifted teeth are also derived. It is hoped that the present investigation may yield a more accurate prediction of the localized stresses at tooth fillets than the results thus far available.

Mechanical Properties on the Welded Connection of Pipe and Hollow Spheres Joints

2011 ◽  
Vol 189-193 ◽  
pp. 3452-3457
Author(s):  
Ya Jie Yan ◽  
Hong Gang Lei ◽  
Xue Yang
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Wall Thickness ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Hollow Spheres ◽  
Steel Structures ◽  
Element Analysis ◽  
Static Tests

Taking pipe - hollow spherical node as the object, and using ANSYS finite element analysis software, established five kinds of finite element model to analyze the stress concentration at the weld connection of the different connections of steel structures - hollow ball under the uniaxial tension. Obtained this node’s stress concentration factor, stress distribution, by changing the hollow spherical diameter and wall thickness, pipe’s diameter and wall thickness, obtained the trend of the stress concentration factor under different control ball matches. Take static tests on typical structures of two specifications 6 hollow sphere nodes, get the measured stress concentration factor, and stress distribution of this node. Through comparative analysis of theoretical analysis and experimental results, show that the two rules are consistent. The research results can provide basis for improving the pipe - hollow spherical joints connecting structural.

Optimum design of perforated symmetric laminates using evolutionary algorithm

2018 ◽  
Vol 53 (23) ◽  
pp. 3281-3305
Author(s):  
A Khechai ◽  
PM Mohite
Keyword(s):  
Genetic Algorithm ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Analytical Solution ◽  
Stress Concentration Factor ◽  
Failure Load ◽  
Composite Plates ◽  
Shear Loading ◽  
Effective Parameters ◽  
Circular Cutout

Here, analytical studies have been carried out to determine the optimal values of effective parameters on the stress concentration factor around a cutout using genetic algorithm. Optimum designs of single lamina as well as symmetric laminates with 4, 8 and 12 layers of graphite/epoxy and glass/epoxy plates containing a circular cutout with various sizes are presented. The work focuses on extending the analytical solution given by Greszczuk to determine the stress distribution in multilayered composite plates subjected to arbitrary in-plane loadings. This is achieved by introducing an arbitrary oriented uniaxial, biaxial and shear loading conditions into Greszczuk solution. In order to mimic as much as possible the real structural behavior, the finite-width correction factor given by Tan is used. Effective parameters on stress distribution around the circular cutout in composite plates considered as design variables include: load angle, fiber orientation, cutout size and stacking sequence of the laminate. The objective function in this study is the minimization of maximum stress concentration around the cutout which is calculated by the present analytical solution. The first ply failure load predicted using Tsai–Wu criterion is maximized for both single lamina and symmetric laminates. Also, the weight of the plates is minimized by increasing the hole size to width ratio. The results obtained by the present analytical solution compare favorably with those obtained using complex variable method. For laminated plate subjected to shear loading, the stress concentration factor decreased drastically by 48.79% compared to a single lamina. The failure load is also increased in most of the loading cases. The results also showed that the genetic algorithm code converges rapidly in most of the cases. The accuracy, quickness, low computational cost and the simplicity of the present solution encourage the designers to use it in practical applications.

Neuber’s rule accounting for the material nonlinearity influence on the stress concentration of the laminated composites

2016 ◽  
Vol 36 (3) ◽  
pp. 214-225 ◽  
Author(s):  
Fathollah Taheri-Behrooz ◽  
Nima Bakhshi
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Material Nonlinearity ◽  
Maximum Deviation ◽  
Linear Solution ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Neuber's Rule

Since holes comprise the necessary features of many structural components, a comprehensive understanding of the behavior of composite plates containing an open hole is a crucial step in their design process. In the present manuscript, an extensive numerical study has been conducted in order to investigate the effects of material nonlinearity on the stress distribution and stress concentration factors in unidirectional and laminated composite materials. To attain this objective, various models with different configurations were studied. In unidirectional composites, the maximum deviation of stress distribution around the hole (from the linear solution) happens in 45° lamina in which includes a high level of shear stress. However, the maximum difference in the stress concentration factor occurs in 15° lamina and is 15.1% at the onset of failure. In composite laminates, the maximum deviation of nonlinear stress concentration factor from the linear solution is reported 24.3% and it occurs in [+45/−45] s laminate. In the last section, Neuber’s rule is employed to find the stress concentration factors of the laminated composites, with a reasonable accuracy.

Plastic Stress Concentration at a Circular Hole in an Infinite Sheet Subjected to Equal Biaxial Tension

1960 ◽  
Vol 27 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Bernard Budiansky ◽  
O. L. Mangasarian
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Strain Hardening ◽  
Circular Hole ◽  
Applied Stress ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Deformation Theory ◽  
Biaxial Tension ◽  
Hardening Material

With the use of J2 deformation theory, the stress-concentration factor at a circular hole in an infinite sheet of strain-hardening material subjected to equal biaxial tension at infinity is found for a variety of representative materials. The analysis exploits a transformation which permits the calculation of the stress-concentration factor without determining the stress distribution in the sheet. Subsequent calculations reveal that, for a monotonically increasing applied stress, the stress history at all points in the sheet is nearly radial.

Numerical stress analysis for fatigue evaluation of welded tubular T-joints

1993 ◽  
Vol 20 (2) ◽  
pp. 269-286 ◽  
Author(s):  
D. I. Nwosu ◽  
A. S. J. Swamidas ◽  
K. Munaswamy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Concentration Factor ◽  
Bending Stress ◽  
Element Analysis ◽  
T Joints ◽  
Shell Finite Element ◽  
Good Agreement

The stress distribution along the intersection of offshore tubular T-joints under the action of axial and in-plane and out-of-plane (bending) brace loading has been investigated using degenerated shell elements. The ratios of through-thickness membrane to bending stress and bending to total stress have been obtained using a simple linear interpolation between the stresses on the inner and outer surfaces of the tube. The nominal brace stress and the maximum principal stress values have been used for stress concentration factor determination. The influence of thickness and other geometric parameters on the stress distribution along the intersection was investigated in two ways, viz., increasing the chord thickness while maintaining a constant brace thickness, and keeping the chord thickness constant while reducing the brace thickness.Comparison of the shell finite-element results obtained in this study with the semiloof thin-shell finite-element results of the University College, London (UCL), exhibits good agreement. Good agreement exists between the results of this study and the UCL parametric equations for the chord and the brace of the joint, with a maximum difference of about 7% on the braceside around the saddle position. Comparisons between the finite-element results and other known parametric equations for stress concentration factor with different diametral, wall thickness, and chord thickness and ratios also show good agreement. A comparison of the results obtained from the finite-element analysis and the experimental results of the Canadian Cooperative Fatigue Studies Program, carried out at Memorial University of Newfoundland and University of Waterloo, is also made. Key words: stress distribution, finite-element analysis, stress concentration factors, membrane stress, bending stress, tubular T-joints.

The Stress Analysis and Experimental Research of Tubular Joints of Offshore Drilling Platform

1984 ◽  
Vol 106 (1) ◽  
pp. 43-45
Author(s):  
T. Y. Chen ◽  
B. Z. Chen ◽  
Y. Q. Wang
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Experimental Research ◽  
Stress Concentration Factor ◽  
Analytical Method ◽  
Concentration Factor ◽  
Offshore Drilling ◽  
Tubular Joints ◽  
Good Agreement

An analytical method for the stress analysis of tubular joints of T, Y, K type is presented in this paper. The stress distribution and stress concentration factor of the joints are calculated. Numerical results are in good agreement with the experimental results.

Parametric Evaluation of Stress Concentration Factor (SCF) at Brace – Chord Intersection of a Ring Stiffened Tubular Joint

2021 ◽  
Author(s):  
G. Chandra Sai Krishna ◽  
S. Nallayarasu
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Parametric Study ◽  
Concentration Factor ◽  
Tensile Load ◽  
Tubular Joints ◽  
Axial Tension ◽  
Axial Tensile ◽  
Brick Element ◽  
Stress Concentration Factors

Abstract Tubular joints are common in offshore framed structures such as jackets. These joints are subjected to fatigue due to cyclic loads from waves. Stress concentration factor plays a major role in the estimation of fatigue life. Studies have been carried out in the past on stress concentration factors for these joints. However, literature on ring stiffened joints is limited. In the present study, numerical simulations have been carried out on ring stiffened tubular joints, especially the T joints, subjected to axial tension load using finite element method in linear analysis using ABAQUS software. A solid type 20-node quadratic brick element (C3D20R) has been used in the study. Stresses in hotspot locations at brace/chord intersection, ring/chord intersection and ring inner edge are examined. The numerical model has been validated using published experimental data and Lloyd’s register recommendations. Further parametric study has been carried out with 20 models, which includes geometric parameters of ring stiffener such as width of stiffener, thickness of stiffener and spacing between the ring stiffeners. The results of parametric study show a significant reduction of SCF at saddle location by placing ring stiffeners in unstiffened T joint. A set of new parametric equations are developed to calculate SCF for ring stiffened T joint at saddle location for axial tensile load.

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