scholarly journals DESCRIBING STRESS CONCENTRATION FACTORS OF AN INTERNALLY PRESSURIZED CYLINDER WITH AN IMBEDDED HOLE BY NEW FORMULATION

2020 ◽  
Author(s):  
javad jafari fesharaki
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Internal Diameter ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
New Formulation ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Pressurized Cylinder

The purpose of this paper is to investigate the stress concentration factor(SCF) for an internallypressurized cylinder with hole and based on detailed three-dimensional elastic FE analysis, a newcomprehensive set of formulas for SCFs are proposed. These stress concentration factors are presentedand discussed as a function of the ratio of cylinder diameter to the thickness of cylinder and hole diameter.The first ratio “D/100t” is equal to 1, 1.25, 1.5, 1.75, 2, 2.5, 2.75, 3, 3.25 and 3.5 and the second ratio“D/10d”, cylinder internal diameter to the hole diameter, varies from 0.6, 0.9, 1.2, 1.5, 1.8, 2, 2.3, 2.7,3.1and 3.5. Results are also presented for SCF of longitudinal, circumferential and Von Mises stresses.

Fatigue Assessment of Dented Rigid Risers

2019 ◽  
Author(s):  
Elvis J. O. Santander ◽  
Bianca Pinheiro ◽  
Carlos Magluta ◽  
Ney Roitman
Keyword(s):  
Stress Concentration ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Element Model ◽  
Oil Fields ◽  
Dimensional Finite Element ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Three Dimensional Finite Element ◽  
Remaining Fatigue Life

Abstract In the development of oil fields, submarine pipelines are used in various applications. These pipelines and risers are subject to accidents that may occur during operation, such as shocks between risers or shocks between a riser and an anchor, rock, or any equipment or heavy object, which may cause mechanical failure, such as dents. The objective of this work is to study of the effect of the introduction of plain dents on the structural integrity of rigid risers under fully reversed bending. A three dimensional finite element model was developed to estimate the stress concentration on dented risers under bending. Several numerical simulations were carried out to evaluate stress concentration factors (SCFs) for varying dimensions of dents and risers, in a parametric study. These SCFs can be used in the prediction of the remaining fatigue life of dented rigid risers.

The Prediction of Three-Dimensional Stress Concentration Factors

1959 ◽  
Vol 63 (585) ◽  
pp. 549-551 ◽  
Author(s):  
I. M. Allison
Keyword(s):  
Stress Concentration ◽  
Mathematical Analysis ◽  
Three Dimensional ◽  
Stress Raiser ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Torsional Loading ◽  
Loading System ◽  
Concentration Factors ◽  
Stress Concentration Factors

Two-Dimensional Stress concentration factors may be obtained more quickly and simply than the corresponding three-dimensional factors, either by experiment or mathematical analysis. It would be convenient to obtain information, for varying geometry in the two-dimensional case of a particular type of stress raiser, e.g. a shoulder, groove or hole, and use this either to predict the three-dimensional stress concentration factors or to extend the range of existing three-dimensional results. Clearly a comparison is only possible if the three-dimensional stress raiser embodies a plane of symmetry (which gives the geometry of the similar two-dimensional stress raiser), and if the loading conditions can be reproduced in both the two- and three-dimensional cases. The latter requirement restricts the correlation to the stress concentration factors obtained in tension and in bending. The three-dimensional torsional loading system has no plane of symmetry which can be simulated in two dimensions.

Using the Palm Computer to Augment the Design of Machine Elements

2000 ◽  
Author(s):  
Terry E. Shoup
Keyword(s):  
Stress Concentration ◽  
Stress Analysis ◽  
Three Dimensional ◽  
The Other ◽  
Machine Design ◽  
State Of Stress ◽  
Machine Elements ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Computational Processes

Abstract This paper discusses the utility of the palm sized computers for augmenting the design of machine elements. Two palm computer programs are presented for handling frequently occurring problems in stress analysis in order to demonstrate the utility of the palm computer in this environment. One of these programs handles the manipulation of a three dimensional state of stress and the other program handles stress concentration factors. These modules facilitate computational processes that would not be possible with a traditional hand-held calculator. These programs are useful for students of machine design and practitioners as well.

Studies in Three-Dimensional Photoelasticity: Stresses in Bent Circular Shafts With Transverse Holes—Correlation With Results From Fatigue and Strain Measurements

1944 ◽  
Vol 11 (1) ◽  
pp. A10-A16
Author(s):  
M. M. Frocht
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Fatigue Tests ◽  
Pure Bending ◽  
Simple Method ◽  
Strain Measurements ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Considerable Work ◽  
Maximum Stresses

Abstract Bent circular shafts with holes in the plane of bending are of frequent occurrence in modern machines. They often form a part of the lubricating system as, for example, in the crankshafts of aircraft engines. Considerable work has been done to determine the maximum stresses and the factors of stress concentration in such shafts. The author presents a simple method of calculating such stresses for transverse holes in pure bending. Experimental photoelastic evidence that led to this method is given. A comparison of the stress-concentration factors obtained by it is made with the published results from fatigue tests and strain measurements from large steel shafts, which were performed a number of years ago at the Westinghouse Research Laboratories.

Determination of stress concentration factors for shafts under tension

2020 ◽  
Vol 62 (4) ◽  
pp. 413-421
Author(s):  
Murat Tolga Ozkan ◽  
Fulya Erdemir
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Numerical Data ◽  
Practical Method ◽  
Ann Model ◽  
Element Analysis ◽  
Design And Optimization ◽  
Concentration Factors ◽  
Stress Concentration Factors

Abstract Computer-based design and optimization have become increasingly important in recent years. This paper has investigated the stress concentration factors (SCF) Kt for shoulder filleted shafts with a hole and without a hole. This study contains two types of shoulder filleted shafts, i. e., a stepped bar of circular cross section with shoulder filleted and a tube with filleted shafts under tension stresses. Investigations on SCF that have been carried out in experimental and theoretical studies, were updated and validated for 2 types of shafts. The charts have been converted into numerical value using high precision computer techniques. Dimensional ratios and SCF were determined using previous work charts. This study determines maximum stresses for shoulder filleted shafts by three dimensional finite element analysis (FEA) and artificial intelligence techniques. A set of SCF charts was converted into numerical values and this data was organized and stored in an Excel file. ANSYS models were created and applied the boundary conditions on the models. And also mesh optimizations were performed. Artificial neural networks (ANN) models were designed using previously collected and verified data. Previous works, ANSYS and ANN results were compared to each other. As a result, ANN model and chart results show a good agreement. The usage of ANN model does not require any mathematical formulae or converting the numerical data action for determining the Kt result for shafts. ANN model usage was identified as a very useful and practical method.

Fatigue Damage of Structural Joints Accounting for Nonlinear Corrosion

2002 ◽  
Vol 46 (04) ◽  
pp. 289-298
Author(s):  
Y. Garbatov ◽  
S. Rudan ◽  
C. Guedes Soares
Keyword(s):  
Stress Concentration ◽  
Fatigue Damage ◽  
Nonlinear Models ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Significant Difference ◽  
Dimensional Finite Element ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Three Dimensional Finite Element

Analysis of the influence of corrosion on the stress concentration factors of typical ship structural details is presented. While traditionally constant stress concentration factors are adopted, it is proposed here to use time-varying stress concentration factors, which result from the progress of corrosion in the structure. Three-dimensional finite-element models are adopted to obtain the detailed stress distribution at different times. Linear and nonlinear models of the effects of corrosion wastage on the plate thickness reduction are considered and stress concentration factors and fatigue damage are calculated as a function of time. It is concluded that the stress concentration factors have a nonlinear dependency with the time and this leads to a significant difference of the fatigue damage of structural components subjected to corrosion as compared with the traditional predictions.

Stress concentration factors in CHS-CFSHS T-joints: Experiments, FE analysis and formulae

2017 ◽  
Vol 151 ◽  
pp. 406-421 ◽  
Author(s):  
L.W. Tong ◽  
G.W. Xu ◽  
D.L. Yang ◽  
F.R. Mashiri ◽  
X.L. Zhao
Keyword(s):  
Stress Concentration ◽  
Fe Analysis ◽  
T Joints ◽  
Concentration Factors ◽  
Stress Concentration Factors

Photoelastic Study and Fatigue Tests of a Contoured, Integrally Reinforced Branch Connection

1971 ◽  
Vol 93 (4) ◽  
pp. 1021-1029
Author(s):  
R. W. Schneider ◽  
W. M. Jackson ◽  
W. R. Nicolls
Keyword(s):  
Stress Concentration ◽  
Internal Pressure ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Bending Moment ◽  
Fatigue Tests ◽  
Extensive Study ◽  
Cylindrical Pressure Vessel ◽  
Concentration Factors ◽  
Stress Concentration Factors

The paper describes the results of an extensive study of a contoured, integrally reinforced branch connection in a cylindrical pressure vessel (or run pipe). Three epoxy models were tested by means of three-dimensional photoelasticity using the stress-freezing and slicing technique. Loads applied were internal pressure, a longitudinal moment on the branch, and a transverse bending moment on the branch; one model was required for each mode of loading. Stress distribution curves are given. In addition, thirteen geometrically similar steel headers were fatigue tested by longitudinal and transverse forces cyclically applied to the branch pipes. Tests were conducted over a range of nominal stress in the branch. Stress concentration factors or stress indices from the photoelastic tests for bending and stress intensification factors from the bending fatigue tests are compared. Stress concentration factors for internal pressure loading, as derived from the photoelastic tests, are presented. Since stress intensification factors are not used to describe fatigue behavior under pulsating pressure, a similar comparison is not possible. Owing to the amount of data accumulated, only the most pertinent are presented; in every instance this includes the area of maximum stress.

Bolt Head Fillet Stress Concentration Factors in Cylindrical Pressure Vessels

2001 ◽  
Vol 123 (3) ◽  
pp. 381-386 ◽  
Author(s):  
Gowri Srinivasan ◽  
Terry F. Lehnhoff
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Three Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Three Dimensional Finite Element ◽  
Circle Diameter ◽  
Maximum Stresses

Linear three-dimensional finite element analysis (FEA) was performed on bolted pressure vessel joints to determine maximum stresses and stress concentration factors in the bolt head fillet as a result of the prying action. The three-dimensional finite element models consisted of a segment of the flanges containing one bolt, using cyclic symmetry boundary conditions. The flanges were each 20 mm in thickness with 901.7 mm inner diameter. The outer flange diameter was varied from 1021 to 1041 mm in steps of 5 mm. The bolt circle diameter was varied from 960.2 to 980.2 mm in steps of 5 mm. The bolts used were 16-mm-dia metric bolts with standard head and nut thickness. The threads were not modeled. The internal vessel pressure was 0.6895 MPa (100 psi). Stress concentration factors in the bolt head fillet were calculated, and they ranged from 3.34 to 4.80. The maximum stress in the bolt as well as the stress concentration factors in the bolt head fillet increase with an increase in bolt circle diameter for a given outer flange dimension. Keeping the bolt circle diameter constant, bolt stress and stress concentration factors in the bolt head fillet decrease with increase in outer flange diameter. The maximum stresses in the bolt were also calculated according to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code and the Verein Deutscher Ingenieur (VDI) guidelines and compared to the results observed through finite element analysis. The stresses obtained through FEA were larger than those predicted by the ASME and VDI methods by a factor that ranged between 2.96 to 3.41 (ASME) and 2.76 to 3.63 (VDI).

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