Finite Element Analysis of Flange Joint With Single and Twin Gaskets Under External Bending Load

2015 ◽  
Author(s):  
N. Rino Nelson ◽  
N. Siva Prasad ◽  
A. S. Sekhar
Keyword(s):  
Finite Element ◽  
Work Performance ◽  
Elevated Temperatures ◽  
Bending Moment ◽  
Element Model ◽  
Pressure Vessels ◽  
Flange Joint ◽  
Element Analysis ◽  
Bending Load ◽  
Gasket Material

Gasketed flange joint is a vital component in pressure vessels and piping systems. Flange joint is usually subjected to bending load due to expansion, wind load, self-weight, etc. Most of the flange design methods use equivalent pressure to include the effect of external bending loads. It becomes complex when the joint is subjected to bending load at elevated temperatures, due to the nonlinear behavior of gasket material. In the present work, performance of the flange joint has been studied under external bending load at elevated temperatures. A 3D finite element model is developed, considering the nonlinearities in the joint due to gasket material and contact between its members along with their temperature dependent material properties. The performance of the joint under different bolt preloads, internal fluid pressures and temperatures is studied. Flange joint with two gaskets (twin gasketed joint) placed beside each other radially, is also analyzed under external bending moment. The maximum allowable bending moments at different internal temperatures, for single and twin gasketed joints with spiral wound gasket are arrived.

A Study on the Behavior of Single- and Twin-Gasketed Flange Joint Under External Bending Load

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
N. Rino Nelson ◽  
N. Siva Prasad ◽  
A. S. Sekhar
Keyword(s):  
Finite Element ◽  
Elevated Temperatures ◽  
Bending Moment ◽  
Pressure Vessels ◽  
Hysteretic Behavior ◽  
Bending Test ◽  
Flange Joint ◽  
Internal Fluid ◽  
Bending Load ◽  
Gasket Material

Gasketed flange joints are widely used in pressure vessels and piping systems. They are subjected to bending load due to differential thermal expansion, wind load, self-weight, etc., in addition to assembly and internal fluid load. Most of the flange designs are based on equivalent pressure method to include the effect of external bending loads. The behavior of gasketed flange joint is complex due to the nonlinear hysteretic behavior of gasket material and contact interfaces between joint members. It becomes more complex when the joint is subjected to bending load at elevated temperatures. In the present work, performance of a flange joint has been studied under internal pressure and external bending load at elevated temperatures. A 3D finite element model is developed, considering the nonlinearities in the joint due to gasket material and contact between its members along with their temperature-dependent material properties. The performance of joint under different bolt preloads, internal fluid pressures, and temperatures is studied. Flange joint with two gaskets (twin-gasketed flange joint, TGJ) placed concentric is also analyzed. The results from finite element analysis (FEA) are validated using four-point bending test on gasketed flange joint. The sealing and strength criteria are considered to determine the maximum allowable bending moment at different internal fluid temperatures, for both single- and twin-gasketed flange joints with spiral wound gasket. Twin gasket is able to withstand higher bending moment without leakage compared to single gasket. Results show that the allowable load on flange joint depends on operating temperature and gasket configuration.

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

Stress and Fatigue Life Modeling of Cannon Breech Closures Including Effects of Material Strength and Residual Stress

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Yield Strength ◽  
Residual Stresses ◽  
Solid Mechanics ◽  
Element Model ◽  
Pressure Vessels ◽  
Material Strength ◽  
Element Analysis

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.

Maximum Stress at Intersecting Bores of Pressurized Blocks

1994 ◽  
Author(s):  
Ajay Garg
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Stress ◽  
Element Model ◽  
Maximum Tensile Stress ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Empirical Methods ◽  
Element Analysis ◽  
Matched Design

Abstract In high pressure applications, rectangular blocks of steel are used instead of cylinders as pressure vessels. Bores are drilled in these blocks for fluid flow. Intersecting bores with axes normal to each other and of almost equal diameters, produce stresses which can be many times higher than the internal pressure. Experimental results for the magnitude of maximum tensile stress along the intersection contour were available. A parametric finite element model simulated the experimental set up, followed by correlation between finite element analysis and experimental results. Finally, empirical methods are applied to generate models for the maximum tensile stress σ11 at cross bores of open and close ended blocks. Results from finite element analysis and empirical methods are further matched. Design optimization of cross bores is discussed.

Investigation of Residual Stress Development During Swage Autofrettage, Using Finite Element Analysis

2009 ◽  
Author(s):  
Michael C. Gibson ◽  
Amer Hameed ◽  
John G. Hetherington
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Axial Stress ◽  
Slope Angle ◽  
Subsequent Development ◽  
Element Model ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Reverse Yielding

Swaging is one method of autofrettage, a means of pre-stressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed through the tube. A Finite Element model of the swaging process was developed, in ANSYS, and systematically refined, to investigate the mechanism of deformation and subsequent development of residual stresses. A parametric study was undertaken, of various properties such as mandrel slope angle, parallel section length and friction coefficient. It is observed that the axial stress plays a crucial role in the determination of the residual hoop stress and reverse yielding. The model, and results obtained from it, provides a means of understanding the swaging process and how it responds to different parameters. This understanding, coupled with future improvements to the model, potentially allows the swaging process to be refined, in terms of residual stresses development and mandrel driving force.

Finite Element Analysis of Local Inelastic Strain Based on Stress Redistribution Locus

2008 ◽  
Author(s):  
Shunji Kataoka ◽  
Takuya Sato
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Loading ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Pressure Vessels ◽  
Stress Redistribution ◽  
Strain Diagram ◽  
Element Analysis ◽  
Inelastic Analysis

Creep-fatigue damage is one of the dominant failure modes for pressure vessels and piping used at elevated temperatures. In the design of these components the inelastic behavior should be estimated accurately. An inelastic finite element analysis is sometimes employed to predict the creep behavior. However, this analysis needs complicated procedures and many data that depend on the material. Therefore the design is often based on a simplified inelastic analysis based on the elastic analysis result, as described in current design codes. A new, simplified method, named, Stress Redistribution Locus (SRL) method, was proposed in order to simplify the analysis procedure and obtain reasonable results. This method utilizes a unique estimation curve in a normalized stress-strain diagram which can be drawn regardless of the magnitude of thermal loading and constitutive equations of the materials. However, the mechanism of SRL has not been fully investigated. This paper presents results of the parametric inelastic finite element analyses performed in order to investigate the mechanism of SRL around a structural discontinuity, like a shell-skirt intersection, subjected to combined secondary bending stress and peak stress. This investigation showed that SRL comprises a redistribution of the peak and secondary stress components and that although these two components exhibit independent redistribution behavior, they are related to each other.

Finite Element Analysis of the Influence of Balance Mode on Rolling Mill Universal Spindle Strength

2014 ◽  
Vol 548-549 ◽  
pp. 449-453 ◽  
Author(s):  
Zhi Qiang Guo ◽  
Ze Lu Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Model ◽  
Rolling Mill ◽  
Loading Condition ◽  
Equivalent Stress ◽  
Bending Moment ◽  
Element Model ◽  
Element Analysis ◽  
Universal Spindle

For the problem of balance bearing of universal spindle in rolling mill being prone to damage, the paper established mechanical model and finite element model of universal spindle. The paper has analyzed that the shear and bending moment in the middle of the shaft is the largest. The fillet near shoulder of balance bearing of the spindle is dangerous part. In order to reduce principal stress of universal spindle caused by moment, the paper improved balance mode of the spindle. The equilibrant was applied from in one place of shaft to put in two places. After optimizing, equivalent stress of the spindle is slight smaller than before under the same loading condition, which illustrates that the strength of the spindle is appropriately improved. Although the effect is not obvious, this has played a guiding role for the optimization of balance mode of universal spindle.

scholarly journals Finite element analysis of dovetail joint made with the use of CNC technology

2010 ◽  
Vol 58 (5) ◽  
pp. 321-328 ◽  
Author(s):  
Václav Sebera ◽  
Milan Šimek
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Models ◽  
Experimental Testing ◽  
Joint Stiffness ◽  
Bending Moment ◽  
Parametric Models ◽  
Cnc Machine ◽  
Element Analysis ◽  
Bending Load

The objective of the paper is the parametrization and the finite element analysis of mechanical pro­per­ties of a through dovetail joint made with the use of a specific procedure by a 3-axis CNC machine. This corner joint was used for the simulation of the bending load of the joint in the angle plane – by compression, i.e. by pressing the joint together. The deformation fields, the stress distribution, the stiffness and the bending moment of the joints were evaluated. The finite element system ANSYS was used to create two parametric numerical models of the joint. The first one represents an ideal­ly stiff joint – both joint parts have been glued together. The second model includes the contact between the joined parts. This numerical model was used to monitor the response of the joint stiffness to the change of the static friction coefficient. The results of both models were compared both with each other and with similar analyses conducted within the research into ready-to-assemble furniture joints. The results can be employed in the designing of more complex furniture products with higher demands concerning stiffness characteristics, such as furniture for sitting. However, this assumption depends on the correction of the created parametric models by experimental testing.

Numerical Analysis of High Pressure Cold Bend Pipe to Investigate the Behaviour of Tension Side Fracture

2012 ◽  
Author(s):  
Celal Cakiroglu ◽  
Amin Komeili ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
Millan Sen
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Internal Pressure ◽  
Experimental Studies ◽  
Element Model ◽  
Combined Loading ◽  
Element Analysis ◽  
Bend Pipe ◽  
Bending Load ◽  
Bending Loads

The cold bend pipelines may be affected by the geotechnical movements due to unstable slopes, soil type and seismic activities. An extensive experimental study was conducted by Sen et al. in 2006 to understand the buckling behaviour of cold bend pipes. In their experiments, it was noted that one high pressure X65 pipe specimen failed under axial and bending loads due to pipe body tensile side fracture which occurred after the development of a wrinkle. The behaviour of this cold bend pipe specimen under bending load has been investigated numerically to understand the conditions leading to pipe body tension side fracture following the compression side buckling. Bending load has been applied on a finite element model of the cold bend by increasing the curvature of it according to the experimental studies conducted by Sen [1]. The bending loads have been applied on the model with and without internal pressure. The distribution of the plastic strains and von Mises stresses as well as the load–displacement response of the pipe have been compared for both load cases. In this way the experimental results obtained by Sen [1] have been verified. The visualization of the finite element analysis results showed that pipe body failure at the tension side of the cold bend takes place under equal bending loads only in case of combined loading with internal pressure.

FEM Stress Analysis and Leakage Behavior of Pipe-Socket Threaded Joints Subjected to Bending Moment and Internal Pressure

2020 ◽  
Author(s):  
Satoshi Nagata ◽  
Shinichi Fujita ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Bending Moment ◽  
Experimental Tests ◽  
Element Analysis ◽  
Contact Conditions ◽  
Sealing Performance ◽  
Bending Load ◽  
Threaded Joints ◽  
Thread Root

Abstract This paper is a report of the studies on the mechanical behaviors and leakage characteristics of pipe-socket threaded joints subjected to bending moment as well as internal pressure by means of experimental tests and finite element simulations. The paper dealt with the 3/4″ and 3″ joints, and the joints for both sizes have two different combinations of thread types in the pipe and socket, i.e. taper-taper thread combination or taper-parallel one, respectively. Experimental bending leak tests showed that the taper-taper joints could retain internal pressure under bending load up to nearly plastic collapse. The taper-parallel joints, however, could hardly keep internal pressure against bending moment even the sealing tape was applied to enhance the sealing performance. Finite element analysis was carried out to simulate those bending tests, especially to clarify the deformation and the stress distribution in the engaged threads in detail. The analysis demonstrated that the sealing performance of the joints highly depend on the contact conditions not only at the thread crest to thread root but also in between flank surfaces. A complicated leak path across the engaged threads under bending moment was identified by the simulation.

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