Design-Focused Stress Analysis of Cylindrical Pressure Vessels Intersected by Small-Diameter Nozzles

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Faisal M. Mukhtar ◽  
Husain J. Al-Gahtani
Keyword(s):  
Shell Theory ◽  
Large Diameter ◽  
Small Diameter ◽  
Vessel Diameter ◽  
Theory Of Elasticity ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Overall Design ◽  
Design Charts ◽  
Thin Shell Theory

In a related work previously carried out by the authors, finite element analysis of cylindrical vessel–cylindrical nozzle juncture based on the use of thin shell theory, due to the fact that the intersecting nozzle sizes are moderate to large, have been presented. Such analysis becomes invalid in cases when the nozzles are small in sizes which may result in nozzles whose configuration violates the validity of shell assumption. As a result, use of solid elements (based on theory of elasticity) in modeling the cylindrical vessels with small-diameter nozzles is presented in the present paper. Discussions of the numerical experiments and the results achieved are, first, given. The results are then compared with the prediction by other models reported in the literature. In order to arrive at the overall design charts that cover all the possible ranges of nozzle-to-vessel diameter ratio, the charts for the vessels with moderate-to-large-diameter nozzles are augmented with those of cylindrical vessels intersected by small-diameter nozzles developed in this work.

An Improved Shell Theory Applied for Failure Analysis of Pressure Vessels

2011 ◽  
Author(s):  
R. Liu ◽  
J. Zhao ◽  
X. J. Wu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Closure ◽  
Shell Theory ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Crack Face ◽  
Theoretical Formulation ◽  
Curvature Effects

Crack-face closure occurs physically at the compressive edges when a shell is subjected to bending loads. However, in traditional shell theories, crack closure effects are not concerned when evaluating the stress intensity factor (SIF). In reality, crack closure effects influence significantly the SIF. This article presents the theoretical and numerical analyses of crack-face closure effects on the stress intensity factor of shells under bending. The theoretical formulation is based on the shallow shell theory of Delale and Erdogan, incorporating the effects of crack-face closure, which are modeled by a line contact at the compressive edges of the crack faces. It is shown that due to curvature effects crack closure in shells may not occur on the entire length of the crack, depending on the nature of the bending loading and the geometry of the shell. To validate the theoretical solution finite element analysis (FEA) is also performed; the two results agree well. As an example, the stress intensity factor for a pressurized cylinder containing an axial crack is determined based on the improved shell theory which takes into account the effects of crack-face closure.

Prediction of Closure Bolt Loads in Small Pressure Vessels: NUREG/CR-6007 vs. Detailed Finite Element Analysis

2010 ◽  
Author(s):  
Charles A. McKeel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Small Diameter ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Containment Vessel ◽  
Fea Model ◽  
Significant Difference ◽  
Load Increase ◽  
The Difference

Closure bolt loads in a flanged cylindrical containment vessel under internal pressure are determined by detailed Finite Element Analysis (FEA) and compared to values determined using NUREG/CR-6007 equations. The containment vessel is of small diameter with an inwardly dished bolted head that geometrically contrasts with the large, flat lidded casks which the NUREG addressed. The comparison showed a significant difference in the magnitude of pressure driven prying load between the FEA model and the NUREG approximate equations. This difference affected the predicted pressure that overcomes preload, and the rate of load increase after preload was exceeded. The difference was likely due to the contrasts between this vessel’s closure shape compared to the more typical flat cask lid shape used in the NUREG development.

scholarly journals Mechanical design of apertures and the infolding of pollen grain

2020 ◽  
Vol 117 (43) ◽  
pp. 26600-26607
Author(s):  
Anže Božič ◽  
Antonio Šiber
Keyword(s):  
Shell Theory ◽  
Mechanical Design ◽  
Pollen Grains ◽  
Theory Of Elasticity ◽  
Pollen Grain ◽  
Elastic Response ◽  
Theoretical Studies ◽  
Elastic Parameters ◽  
Folding Pathways ◽  
Thin Shell Theory

When pollen grains become exposed to the environment, they rapidly desiccate. To protect themselves until rehydration, the grains undergo characteristic infolding with the help of special structures in the grain wall—apertures—where the otherwise thick exine shell is absent or reduced in thickness. Recent theoretical studies have highlighted the importance of apertures for the elastic response and the folding of the grain. Experimental observations show that different pollen grains sharing the same number and type of apertures can nonetheless fold in quite diverse fashions. Using the thin-shell theory of elasticity, we show how both the absolute elastic properties of the pollen wall and the relative elastic differences between the exine wall and the apertures play an important role in determining pollen folding upon desiccation. Focusing primarily on colpate pollen, we delineate the regions of pollen elastic parameters where desiccation leads to a regular, complete closing of all apertures and thus to an infolding which protects the grain against water loss. Phase diagrams of pollen folding pathways indicate that an increase in the number of apertures leads to a reduction of the region of elastic parameters where the apertures close in a regular fashion. The infolding also depends on the details of the aperture shape and size, and our study explains how the features of the mechanical design of apertures influence the pollen folding patterns. Understanding the mechanical principles behind pollen folding pathways should also prove useful for the design of the elastic response of artificial inhomogeneous shells.

Some Comments on the Stress Concentration and Shakedown Factors for Spherical Pressure Vessels with Flush Radial Cylindrical Nozzles

1979 ◽  
Vol 21 (3) ◽  
pp. 153-157 ◽  
Author(s):  
M. Robinson
Keyword(s):  
Stress Concentration ◽  
Experimental Work ◽  
Stress Concentration Factor ◽  
Thin Shell ◽  
Shell Theory ◽  
Pressure Vessels ◽  
Simple Design ◽  
Design Proposal ◽  
Thin Shell Theory ◽  
Spherical Pressure

Some previous theoretical shakedown pressures for a cylinder—sphere vessel under internal pressure are, for a certain range of parameters, shown to be too high. The error can be traced to an underestimate of the stress concentration factor owing to the use of the centreline thin-shell theory and the neglect of cylinder stresses. It is shown that much more theoretical and experimental work needs to be done to establish reliable shakedown pressures for a comprehensive range of parameters. A simple design proposal is suggested which should meanwhile prove adequate.

Effects of Residual Stress on Fatigue Strength of Small-Diameter Welded Pipe Joint

1997 ◽  
Vol 119 (4) ◽  
pp. 428-434 ◽  
Author(s):  
T. Yamashita ◽  
T. Hattori ◽  
K. Iida ◽  
T. Nomoto ◽  
M. Sato
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Large Diameter ◽  
Small Diameter ◽  
Local Stress ◽  
Element Analysis ◽  
Fillet Weld ◽  
Pipe Joints ◽  
Welded Pipe

Bending fatigue tests were conducted to investigate the fatigue strength of small-diameter socket welded pipe joints. In most cases of large-diameter socket joints, a fatigue crack started from the root of the fillet weld, though the stress amplitude at the root was smaller than that at the toe of the fillet weld. Additionally, the fatigue strength was affected by the weld bead sequence. The residual stress was considered to be one of the important parameters governing fatigue strength; therefore, its effects were investigated. In several types of pipe joints, the local stress and residual stress distributions were calculated by finite element analysis. The residual stresses were compressive at the toe and tensile at the root of the socket welded joints. Based on these results, the effects of residual stresses on the fatigue strength are discussed for small-diameter welded pipe joints in the present work.

Settlement Analysis of Single Large-Diameter and Super-Long Bored Piles in Cohesive Soils

2012 ◽  
Vol 594-597 ◽  
pp. 320-326 ◽  
Author(s):  
Rui Kun Zhang ◽  
Ming Lei Shi ◽  
Jin Wang
Keyword(s):  
Hybrid Method ◽  
Load Transfer ◽  
Large Diameter ◽  
Soft Clay ◽  
Small Diameter ◽  
Transfer Characteristic ◽  
Single Pile ◽  
Element Analysis ◽  
Bored Piles ◽  
Axially Loaded

The behavior of single axially loaded large-diameter and super-long bored piles have large difference to single small diameter short piles. The article analyzes the load transfer characteristic of single axially loaded large-diameter and super-long bored piles in deep soft clay in the Yangtze River Delta region. And the hybrid method of finite element analysis of rod structure coupling with the shear displacement method for single pile was utilized to simulating and predicting the single pile performance. It is verified that the settlement calculation hybrid method in this paper is reliable.

Finite Element Analysis of Nozzle Dimension Influence on Fluidic Gyroscope Performance

2013 ◽  
Vol 756-759 ◽  
pp. 4690-4693
Author(s):  
Jing Bo Chen ◽  
Lin Hua Piao ◽  
Jin Tang
Keyword(s):  
Finite Element ◽  
Sensitive Element ◽  
Model Building ◽  
Large Diameter ◽  
Small Diameter ◽  
Two Dimensional ◽  
Element Analysis ◽  
Temperature Changes ◽  
Equation Solving ◽  
Element Simulation

In this paper, research the influence on nozzle dimension in the sensitive element of fluidic gyroscope. Airflow of two different nozzle dimensions is analyzed contrastively in the sensitive element of fluidic gyroscope. Using ANSYS-FLOTRAN CFD software, the finite element simulation is conducted by a series of procedures, such as two-dimensional model building of fluidic gyroscope, meshing, loads applying and equation solving. The two dimensional airflow distributions of different nozzle diameters in sensitive element of fluidic gyroscope are calculated. The results show that, compared with large diameter and small diameter nozzle of fluidic gyroscope, airflow velocity in the outlet increases by 10.1%, and 31.3% of velocity in the nozzle in large diameter nozzle. It promotes airflow circulation and reduces airflow accumulation in the sensitive cavity without any vortex increase in large nozzle, it increases thermal wires temperature changes and improves the resolution and sensitivity of fluidic gyroscope.

On the Use of Theory of Rings on Nonlinear Elastic Foundation to Study the Effect of Bolt Spacing in Bolted Flange Joints

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Tan Dan Do ◽  
Abdel-Hakim Bouzid ◽  
Thien-My Dao
Keyword(s):  
Elastic Foundation ◽  
Contact Stress ◽  
Large Diameter ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Linear Elastic ◽  
Circumferential Distribution ◽  
Bolted Flange ◽  
Nonlinear Elastic ◽  
Bolt Spacing

Bolted flange joints are extensively used to connect pressure vessels and piping equipment together. They are simple structures that offer the possibility of disassembly. However, they often experience leakage problems due to a loss of tightness as a result of a nonuniform distribution of gasket contact stresses in the radial and circumferential direction. Many factors contribute to such a failure; the flange and gasket stiffness and bolt spacing design combination being one of them. In our recent paper, the effects of bolt spacing were investigated based on the theory of circular beams resting on a linear elastic foundation (Do, T. D., Bouzid, A. H., and Dao, T.-M., 2011, “Effect of Bolt Spacing on the Circumferential Distribution of Gasket Contact Stress in Bolted Flange Joints,” ASME J. Pressure Vessel Technol., 133 (4), 041205). This paper is an extension of the work in which an analytical solution based on the real nonlinear gasket behavior is developed. This study focuses on the distribution of the gasket contact stress of two large diameter flanges, namely, a 52 in. and a 120 in. heat exchanger (HE) flanges. The nonlinear gasket behavior solution is compared to the Finite Element Analysis (FEA) and the linear gasket behavior solution for evaluation and comparison.

The Method of Design by Analysis for Cylindrical Pressure Vessels with Spherically Dished Head

2019 ◽  
Vol 795 ◽  
pp. 262-267
Author(s):  
Zhen Yu Wang ◽  
Jian Wu ◽  
Ming De Xue ◽  
Shi Yu Li
Keyword(s):  
Internal Pressure ◽  
Shell Theory ◽  
Pressure Vessels ◽  
Design Criteria ◽  
Analysis Method ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Nonlinear Elastic ◽  
Theoretical Stress ◽  
Thin Shell Theory

Standards GB 150.3-2011 and JB4732-1995 (Confirmed in 2005) provide design methods for the cylindrical pressure vessels with spherically dished head under internal pressure. It is available for the ratio of the internal pressure p to the allowable stress Sm, p/Sm≥0.002. Engineers desire the design curves for p/Sm<0.002. This paper presents a stress analysis method based on elastic thin shell theory for a spherically dished head jointed to the end or the middle of the cylindrical shell. The design criteria in the current standards are modified. Based on the theoretical stress solution and design criteria, the suitable range of the design curves is extended to p/Sm≥0.001. Nonlinear elastic perfectly-plastic finite element method ensures the reliability of the design curves.

scholarly journals Finite Element Analysis of Oil and Gas Field Development Completion Tool Based on ANSYS

2021 ◽  
Vol 252 ◽  
pp. 03020
Author(s):  
Yanli Liu ◽  
Daqi Fu ◽  
Gaofeng Zhang ◽  
Yanzheng Yang ◽  
Haijun Zhang ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Large Diameter ◽  
Small Diameter ◽  
Gas Field ◽  
Element Analysis ◽  
Field Development ◽  
Variable Diameter ◽  
Casing Damage ◽  
Oil And Gas Field ◽  
Suitable Structure

At persent, multi expandable patching can’t be operated below the patched period of casing damage wells, a varible diameter expandable cone has been designed, so expandable tools can be put into wells with small diameter and expanded with large diameter which can achieve the purpose of patching for casing damage wells for many times. The indoor prototype testing showed that the tools had a suitable structure, start-up pressure was 3–5MPa,complete closure pressure was 52MPa,maximum overall diameter increased from 188 mm to 220 mm, with the same size of conventional expandable cone, expandable rate was 17.02%.The research results showed that expandable force increases linearly with the increase of thrust, expandable tools could be put into wells with small diameter and expanded with large diameter with the help of variable diameter expandable cone, it should have a broad application prospect after rudcing the closure pressure.

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