Finite Element Simulation of Bolt-Up Process of Pipe Flange Connections With Spiral Wound Gasket

2003 ◽  
Vol 125 (4) ◽  
pp. 371-378 ◽  
Author(s):  
Toshimichi Fukuoka ◽  
Tomohiro Takaki
Keyword(s):  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Numerical Approach ◽  
Exponential Equation ◽  
Flange Connection ◽  
Element Simulation ◽  
Highly Nonlinear ◽  
Strain Relationship ◽  
Relationship Of ◽  
Spiral Wound

It is well known that a large amount of scatter in bolt preloads is observed when bolting up a pipe flange connection, especially in the case of using a spiral wound gasket. In this study, a numerical approach is proposed, which can simulate the bolt-up process of a pipe flange connection with a spiral wound gasket inserted. The numerical approach is designed so as to predict the scatter in bolt preloads and achieve uniform bolt preloads at the completion of pipe flange assembly. To attain the foregoing purposes, the stress-strain relationship of a spiral wound gasket, which shows highly nonlinear behavior, is identified with a sixth-degree polynomial during loading and with an exponential equation during unloading and reloading. Numerical analyses are conducted by three-dimensional FEM, in which a gasket is modeled as groups of nonlinear one-dimensional elements.

Methodical Guideline for Bolt-Up Operation of Pipe Flange Connections: A Case Using Sheet Gasket and Spiral Wound Gasket

2003 ◽  
Author(s):  
Tomohiro Takaki ◽  
Toshimichi Fukuoka
Keyword(s):  
Finite Element Analysis ◽  
Element Analysis ◽  
Flange Connection ◽  
Nominal Size ◽  
Nonlinear Stress ◽  
Strain Relationship ◽  
Simplified Modeling ◽  
Relationship Of ◽  
Representative Material ◽  
Spiral Wound

The purpose of this study is the proposal of guidelines for bolt-up operation of pipe flange connections with joint sheet gasket or spiral wound gasket. Numerical calculations are systematically executed for pipe flanges with wide variety of nominal size by using finite element analysis, which can simulate the bolt-up process of a pipe flange connection, because the tightening performance of the pipe flange connection largely depends on the bolt-up process. Gaskets also have dominant effects on the tightening performance. It is, however, impossible to determine the number of tightening passes to get uniform bolt preloads for all kinds of gaskets. A simplified modeling method of nonlinear stress-strain relationship of gasket is, therefore, evaluated and a representative material property of gasket is selected to develop the bolt assembly guideline. The bolt-up procedure, in which four bolts located 90 degrees from each other are tightened with the same magnitude of preload at the installation process, is investigated.

STRESS-STRAIN RELATIONSHIP OF ZR55AL10NI5CU30 METALLIC GLASS ANALYZED BY 3D IMAGES ON SPHERICAL INDENTS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2453-2458 ◽  
Author(s):  
YUN-HEE LEE ◽  
JONG SEO PARK ◽  
HAE MOO LEE ◽  
SEUNG HOON NAHM
Keyword(s):  
Metallic Glass ◽  
Metallic Glasses ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Polished Surface ◽  
Flow Properties ◽  
Stress Strain ◽  
Strain Relationship ◽  
Relationship Of

Mechanically polished surface of Zr 55 Al 10 Ni 5 Cu 30 metallic glass was indented with a rigid ball 0.5 mm in diameter and its corresponding load-depth curve was recorded automatically. Although a stress-strain relationship beneath the indenter can be analyzed from the raw indentation curve, the current analysis developed for crystalline solids can mislead erroneous properties because it does not consider significant material pile-ups in amorphous metallic glasses. Thus, we proposed a novel indent image processing technique for characterizing the contact and flow properties in the metallic glasses; the contact area was measured by differentiating a three-dimensional indent morphology digitized by a surface profiler and a surface-stretching strain was newly defined in order to estimate the flow properties. Finally, the work-hardening index estimated was about 0.05, comparable with the typical value measured from uniaxial compression in the Zr -based metallic glass.

Triaxial Test and Numerical Analysis on the Fiber Reinforced Laterite Clay

2013 ◽  
Vol 275-277 ◽  
pp. 1219-1224 ◽  
Author(s):  
Jin Li Zhang ◽  
Man Yuan ◽  
Zheng Guo Jiang ◽  
Qing Yang
Keyword(s):  
Three Dimensional ◽  
Calculation Model ◽  
Secondary Development ◽  
Triaxial Tests ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Nonlinear Fitting ◽  
Strain Relationship ◽  
Straight Lines ◽  
Relationship Of

Triaxial compressive tests were performed on laterite clay(LC) reinforced with different fiber contents and lengths. It was observed that the curves of stress-strain have a segmented characteristic at the critical strain. The stress-strain curves of fiber reinforced laterite clay(FRLC) were expressed by the combination of hyperbola and straight lines. The parameters of stress-strain curves were obtained by linear and nonlinear fitting method with experimental results. A three-dimensional calculation model of triaxial tests was developed on the basis of ABAQUS software. To express the stress-strain relationship of hyperbola-straight lines, user’s subroutine was established through secondary development. Based on the test conditions, a large number of calculations were conducted. There is a good agreement between the results of numerical calculations and tests. It shows that the stress-strain relationship of FRLC can be described by the hyperbola-straight line combination model.

scholarly journals 3D Morphology Distribution Characteristics and Discrete Element Simulation of Sand-Gravel Mixtures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wu Qi ◽  
Sun Suyu ◽  
Gao Guangliang ◽  
Fang Yi ◽  
Chen Guoxing
Keyword(s):  
Surface Texture ◽  
Coarse Aggregate ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Interparticle Contact ◽  
Coarse Aggregates ◽  
3D Morphology ◽  
Element Simulation ◽  
Proposed Model ◽  
Sand And Gravel

Sand-gravel mixtures are typical binary materials, exhibiting highly heterogeneous, discontinuous, and significant structural effects. The contact state between sand and gravel particles has a significant influence on the mechanical properties of the mixtures. This article focused on the complex internal structure and its mesostructural behavior of the mixtures, and a systematic statistical analysis was carried out to study the shape, size, and angularity of the coarse particles. The three-dimensional (3D) shapes of coarse aggregates were approximated to be hexahedron, pentahedron, and tetrahedron. An indicator called angularity and surface texture (AT) index was developed to characterize the combined effect of the coarse aggregate angularity and surface texture. Based on the screening testing and digital image processing, the particle size and AT index of aggregates were extracted, and their means, standard deviations, and statistical distributions were studied. An algorithm for generating 3D aggregates was developed based on the statistical results of the coarse aggregate 3D morphology. The coarse aggregate generating code was written using the fish language in PFC3D. The numerical model was then applied to conduct three typical monotonic or cyclic triaxial test simulations. Retrospective simulation of the laboratory tests using the proposed model showed good agreement, and the reliability of the model is effectively verified. The results interpreted well the mechanism of particle motion and the distribution of interparticle contact force during shearing from mesoscale of the mixtures, which can give better understanding and modeling of the nonlinear behavior of the sand-gravel mixtures.

scholarly journals Hydromechanical modeling of granular soils considering internal erosion

2020 ◽  
Vol 57 (2) ◽  
pp. 157-172 ◽  
Author(s):  
Jie Yang ◽  
Zhen-Yu Yin ◽  
Farid Laouafa ◽  
Pierre-Yves Hicher
Keyword(s):  
Experimental Data ◽  
Mechanical Behavior ◽  
Fine Particles ◽  
Numerical Approach ◽  
Internal Erosion ◽  
Erosion Process ◽  
Incremental Model ◽  
Strain Relationship ◽  
Practical Model ◽  
Relationship Of

This paper attempts to formulate a coupled practical model in the framework of continuum mechanics to evaluate the phenomenon of internal erosion and its consequences on the mechanical behavior of soils. For this purpose, a four-constituent numerical approach has been developed to describe the internal erosion process. The detachment and transport of the fine particles have been described by a mass exchange formulation between the solid and fluid phases. The stress–strain relationship of the soil is represented by a nonlinear incremental model. Based on experimental data, this constitutive model has been enhanced by the introduction of a fines content–dependent critical state, which allows accounting for the influence of fines on soil deformation and strength. The applicability of the practical approach to capture the main features of the internal erosion process and its impact on the mechanical behavior of the eroded soil have been validated by comparing numerical and experimental results of internal erosion tests on Hong Kong completely decomposed granite (HK-CDG) mixtures, which demonstrated that the practical model was able to reproduce, with reasonable success, the experimental data. Furthermore, the influence of the stress state, the initial soil density, and the initial fraction of fines have been analyzed through numerical simulations using the proposed model.

Finite Element Simulation of Bolt-Up Process of Pipe Flange Connections

2000 ◽  
Vol 123 (3) ◽  
pp. 282-287 ◽  
Author(s):  
Toshimichi Fukuoka ◽  
Tomohiro Takaki
Keyword(s):  
Finite Element ◽  
Contact Problem ◽  
Finite Element Simulation ◽  
Arbitrary Order ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Numerical Analyses ◽  
Elastic Contact ◽  
Element Simulation ◽  
Bolt Preload

Achieving uniform bolt preload is difficult when tightening a pipe flange with a number of bolts. Several bolt-tightening strategies have been proposed so far for achieving uniform bolt preloads. It seems, however, that effective guidelines for tightening pipe flange connections have not been established. In this study, a numerical approach is presented for estimating the scatter in bolt preloads and achieving the uniform bolt preloads when tightening each bolt one by one in an arbitrary order. Numerical analyses are conducted using three-dimensional FEM as an elastic contact problem. The analytical objects are pipe flanges specified in JIS B 2238 with an aluminum gasket inserted. The validity of the numerical procedures proposed here is ascertained by experiment.

Modeling and Assessment of the Produced Water Discharges from Offshore Petroleum Platforms

2007 ◽  
Vol 42 (4) ◽  
pp. 303-310 ◽  
Author(s):  
Zhi Chen ◽  
Lin Zhao ◽  
Kenneth Lee ◽  
Charles Hannath
Keyword(s):  
Random Walk ◽  
Produced Water ◽  
Model Development ◽  
Three Dimensional ◽  
Monitoring Program ◽  
Ecological Monitoring ◽  
Numerical Approach ◽  
Ocean Model ◽  
Scale Model ◽  
Water Stream

Abstract There has been a growing interest in assessing the risks to the marine environment from produced water discharges. This study describes the development of a numerical approach, POM-RW, based on an integration of the Princeton Ocean Model (POM) and a Random Walk (RW) simulation of pollutant transport. Specifically, the POM is employed to simulate local ocean currents. It provides three-dimensional hydrodynamic input to a Random Walk model focused on the dispersion of toxic components within the produced water stream on a regional spatial scale. Model development and field validation of the predicted current field and pollutant concentrations were conducted in conjunction with a water quality and ecological monitoring program for an offshore facility located on the Grand Banks of Canada. Results indicate that the POM-RW approach is useful to address environmental risks associated with the produced water discharges.

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