The Simulation and Assessment of Compressed Natural Gas Storage Well With Defects

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Wei Tan ◽  
JinJun Zhang ◽  
WeiFei Niu ◽  
ZeJun Wang ◽  
ShiLai Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Natural Gas ◽  
Iterative Methods ◽  
Fem Analysis ◽  
Limit Load ◽  
Liquefied Petroleum Gas ◽  
Element Analysis ◽  
Compressed Natural Gas ◽  
Load Analysis ◽  
Influence Radius

Compressed natural gas (CNG) is a fossil fuel substitute for gasoline (petrol), diesel, or propane/LPG (liquefied petroleum gas). Nowadays, there are three ways used to store CNG: gas bottles group, jumbo tubes trailer, and CNG storage well. The technology of storage well came into use in the early 1990s in China and nowadays, there are more than 5000 CNG storage wells in use. In this paper, the CNG storage well is introduced with the structure, advantages, and the technology of construction. Compared with other CNG containers, storage well has the following advantages: safer and more reliable, accident-preventive, space-saving, and longer life expectancy. The feasibility of IRIS (internal rotary system) used for storage well NDT (Nondestructive testing) is also studied. And the CNG well with defects are assessed as well. To investigate the validity of IRIS in detecting the storage well, an interval casing with man-made defects is tested. FEM (finite element method), combined with the method in JB4732 (Chinese industry standard) is used to analyze the storage well with inner corrosion pits, and evaluate the fatigue life. The linear elastic FEA (finite element analysis) of storage with single, two, and three defects is performed. The limit load analysis is also discussed with two different iterative methods. The result shows that IRIS can be used in detecting internal and external defects and recording the information. The simulation indicates that the pit along the axis direction is more dangerous than the one on any other direction and the influence radius of pit is the length of defect. The two different iterative methods used in limit load analysis finally lead to a consensus. The IRIS can be adopted in storage well. It can detect the defects on the internal and external surface of casing and record the detailed information. A database should be built to record defect information for each storage well. On the basis of IRIS detection and FEM analysis, determines whether a well can survive or not until next detection carried on by the method proposed in this paper.

Study on the Effect of Axial Flaw Length on Limit Bending Load of Wall Thinned Straight Pipes by Large Strain Finite Element Analyses

2012 ◽  
Author(s):  
Yoshiaki Ito ◽  
Toshiyuki Meshii
Keyword(s):  
Finite Element ◽  
Fracture Mode ◽  
Large Strain ◽  
Local Stress ◽  
Limit Load ◽  
Crack Model ◽  
Element Analysis ◽  
Bending Load ◽  
Load Analysis ◽  
Planar Flaw

In this paper, we examined the effect of axial flaw length δz (Fig. 1) on limit bending load Mc of wall-thinned straight pipes by large strain finite element analysis (FEA). In the past, Han et al. [1] studied the effect of axial flaw length δz on limit bending load Mc of wall-thinned straight pipes by limit-load analyses. Han et al.’s [1] results indicated the trend which the Mc monotonically decreased with the increase in δz. If this finding is accepted, the Mc for a crack is larger than that for a non-planar flaw (wall thinning), and as a result, using the crack model for a non-planar flaw would be non-conservative. In contrast, Tsuji and Meshii [2] demonstrated by their tests that the Mc showed the maximum for a small δz. They estimated that this inconsistency was mainly due to the fact that Han et al. [1] and other researchers always assumed the fracture mode as the collapse, but the cracking was observed in Tsuji’s [2] experiment for small δz. Therefore in this work, we examined the effect of axial flaw length δz on limit bending load Mc of wall-thinned straight pipes by large strain FEA and applying Domain Collapse Criterion (DCC) [3] (which can predict fracture mode and the Mc accurately) to FEA results. In concrete, we attempted to reproduce Tsuji and Meshii’s experimental results [2] by FEA that the Mc showed the maximum for a small δz. In addition, we tried to understand the reason why limit-load analysis failed to predict this tendency. The results showed that large strain FEA with DCC [3] reproduced the Mc-δz relationship observed in the experiments. The inconsistency of Mc-δz relationship between Tsuji and Meshii’s experiment [2] and Han et al.’s limit-load analysis [1] and others analysis was estimated on due to the limit-load analysis failed to predict the failure for the flaw with a small δz, in which the failure mode is governed by the local stress (cracking) and not by the plastic deformation in a large volume (collapse).

Use of Limit Load Analysis for Design of Pressure Vessel Cover

2012 ◽  
Author(s):  
Rahul Jain
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Limit Load ◽  
Plastic Limit ◽  
Element Analysis ◽  
Linear Elastic ◽  
Reference Volume ◽  
Plastic Limit Load ◽  
Load Analysis

This paper explores the use of limit load analysis methods for the design of a pressure vessel manway cover as per the ASME boiler and pressure vessel code guidelines. The results of elastic and limit load finite element analysis are discussed for the design. The concept of reference volume consideration along with linear elastic finite element analysis to determine the lower bound limit load has been explored and the results are compared with the non-linear elastic-plastic limit load analysis.

scholarly journals An Optimum Fatigue Design of Polymer Composite Compressed Natural Gas Tank Using Hybrid Finite Element-Response Surface Methods

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 483
Author(s):  
Kazem Reza Kashyzadeh ◽  
Seyed Saeid Rahimian Koloor ◽  
Mostafa Omidi Bidgoli ◽  
Michal Petrů ◽  
Alireza Amiri Asfarjani
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Natural Gas ◽  
Response Surface ◽  
Polymer Composite ◽  
Wall Thickness ◽  
Composite Shell ◽  
Compressed Natural Gas ◽  
Fiber Angle ◽  
Composite Tank

The main purpose of this research is to design a high-fatigue performance hoop wrapped compressed natural gas (CNG) composite cylinder. To this end, an optimization algorithm was presented as a combination of finite element simulation (FES) and response surface analysis (RSA). The geometrical model was prepared as a variable wall-thickness following the experimental measurements. Next, transient dynamic analysis was performed subjected to the refueling process, including the minimum and maximum internal pressures of 20 and 200 bar, respectively. The time histories of stress tensor components were extracted in the critical region. Furthermore, RSA was utilized to investigate the interaction effects of various polymer composite shell manufacturing process parameters (thickness and fiber angle) on the fatigue life of polymer composite CNG pressure tank (type-4). In the optimization procedure, four parameters including wall-thickness of the composite shell in three different sections of the CNG tank and fiber angle were considered as input variables. In addition, the maximum principal stress of the component was considered as the objective function. Eventually, the fatigue life of the polymer composite tank was calculated using stress-based failure criterion. The results indicated that the proposed new design (applying optimal parameters) leads to improve the fatigue life of the polymer composite tank with polyethylene liner about 2.4 times in comparison with the initial design.

Radon concentration in compressed natural gas and liquefied petroleum gas and its release range in residential houses

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Akbar Abbasi ◽  
Hesham M.H. Zakaly ◽  
Mahmoud M. Hessien
Keyword(s):  
Natural Gas ◽  
Radon Concentration ◽  
Concentration Distribution ◽  
Measurement Techniques ◽  
Concentration Measurement ◽  
Liquefied Petroleum Gas ◽  
Compressed Natural Gas ◽  
Radon Exposure ◽  
Active Method

Abstract Radon (222Rn) exposure in the environment is an important issue, and many pathways exist for radon exposure to humans. One of these pathways is 222Rn release through the consumption of natural gas. The issues of 222Rn concentration measurement techniques and worldwide concentration distribution were reviewed in natural gas, with emphasis on performing an active method to determine 222Rn concentration in LPG and CNG gases used in Cyprus. The obtained results were compared with 222Rn concentration in natural gas worldwide and UNSCEAR reports. The average 222Rn concentration value in LPG gas was observed higher than CNG gas. Also, the 222Rn concentration in LPG and CNG gases was less than the UNSCEAR reported value.

scholarly journals Effect of Ovality in Inlet Pigtail Pipe Bends Under Combined Internal Pressure and In-Plane Bending for Ni-Fe-Cr B407 Material

2017 ◽  
Vol 62 (3) ◽  
pp. 1881-1887
Author(s):  
P. Ramaswami ◽  
P. Senthil Velmurugan ◽  
R. Rajasekar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Limit Load ◽  
Outer Radius ◽  
Factor H ◽  
Geometrical Shape ◽  
Element Analysis ◽  
Pipe Bend ◽  
Plane Bending

Abstract The present paper makes an attempt to depict the effect of ovality in the inlet pigtail pipe bend of a reformer under combined internal pressure and in-plane bending. Finite element analysis (FEA) and experiments have been used. An incoloy Ni-Fe-Cr B407 alloy material was considered for study and assumed to be elastic-perfectly plastic in behavior. The design of pipe bend is based on ASME B31.3 standard and during manufacturing process, it is challenging to avoid thickening on the inner radius and thinning on the outer radius of pipe bend. This geometrical shape imperfection is known as ovality and its effect needs investigation which is considered for the study. The finite element analysis (ANSYS-workbench) results showed that ovality affects the load carrying capacity of the pipe bend and it was varying with bend factor (h). By data fitting of finite element results, an empirical formula for the limit load of inlet pigtail pipe bend with ovality has been proposed, which is validated by experiments.

J-Integral Analysis of Surface Cracks in Round Bars under Bending Moments

2011 ◽  
Vol 52-54 ◽  
pp. 43-48 ◽  
Author(s):  
Al Emran Ismail ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Mariyam Jameelah Ghazali ◽  
Ruslizam Daud
Keyword(s):  
Finite Element ◽  
Crack Depth ◽  
Crack Tip ◽  
Bending Moment ◽  
Limit Load ◽  
Fe Model ◽  
Surface Cracks ◽  
Element Analysis ◽  
Reference Stress ◽  
Proposed Model

This paper presents a non-linear numerical investigation of surface cracks in round bars under bending moment by using ANSYS finite element analysis (FEA). Due to the symmetrical analysis, only quarter finite element (FE) model was constructed and special attention was given at the crack tip of the cracks. The surface cracks were characterized by the dimensionless crack aspect ratio, a/b = 0.6, 0.8, 1.0 and 1.2, while the dimensionless relative crack depth, a/D = 0.1, 0.2 and 0.3. The square-root singularity of stresses and strains was modeled by shifting the mid-point nodes to the quarter-point locations close to the crack tip. The proposed model was validated with the existing model before any further analysis. The elastic-plastic analysis under remotely applied bending moment was assumed to follow the Ramberg-Osgood relation with n = 5 and 10. J values were determined for all positions along the crack front and then, the limit load was predicted using the J values obtained from FEA through the reference stress method.

Method for Tensile Measurement of Stud-Less Mooring Chain

2013 ◽  
Vol 718-720 ◽  
pp. 703-708 ◽  
Author(s):  
Yu Du ◽  
Wen Hua Wu ◽  
Qian Jin Yue
Keyword(s):  
Finite Element ◽  
Deformation Characteristic ◽  
Fem Analysis ◽  
Ansys Software ◽  
Mooring Lines ◽  
Element Analysis ◽  
Present Measurement ◽  
Assessment Design ◽  
Shape Characteristics ◽  
Mooring Chain

Tension of mooring chain is the principle characteristic for mooring system. Tensile value which derived from on-site mooring lines could be used for risk assessment, design evaluation etc. It is hard to obtain underwater tension of mooring chain by traditional method, such as strain gauge, FBG, etc. A new tensile measure method is present based on finite element analysis and shape characteristics of stud-less mooring chain. At first, deformation of stud-less mooring chains is analyzed by finite element method and Ansys software. Then, a design of tension-meter is developed on the basis of the deformation characteristic due to the above FEM analysis. Finally, a model calibrate is designed and tested to prove feasibility of present measurement method.

A Determination of Material Properties of Flexible Structures Using EMA and FEM Analysis

2014 ◽  
Vol 693 ◽  
pp. 293-298 ◽  
Author(s):  
Rastislav Duris
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Low Cost ◽  
Flexible Structures ◽  
Fem Analysis ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Vibration Data ◽  
Complex Interactions ◽  
Applied Forces

Dynamic behavior of mechanical structures results from complex interactions between applied forces and the stiffness properties of the structure. Currently, many problems of structural dynamic analysis are solved using Finite Element Method (FEM). However, in recent years, the implementation of the Fast Fourier Transform (FFT) in low cost computer-based signal analyzers has provided a powerful tool for acquisition and analysis of vibration data. This article discusses combination of two approaches to structural dynamics testing; the experimental part which is referred to as Experimental Modal Analysis (EMA), respectively the analytical part, which is realized by Finite Element Analysis (FEA). Main goal of the paper is calculation of material properties from experimentally determined modal frequencies.

The Evaluation of Failure Pressure for Corrosion Defects Within Girth or Seam Weld in Transmission Pipelines

2004 ◽  
Author(s):  
Young-pyo Kim ◽  
Woo-sik Kim ◽  
Young-kwang Lee ◽  
Kyu-hwan Oh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Limit Load ◽  
The Body ◽  
Element Analysis ◽  
Burst Test ◽  
Corrosion Defect ◽  
Seam Weld ◽  
Failure Assessment ◽  
Corrosion Defects

The failure assessment for corroded pipeline has been considered with the burst test and the finite element analysis. The burst tests were conducted on 762mm diameter, 17.5mm wall thickness and API 5L X65 pipe that contained specially manufactured rectangular corrosion defect. The failure pressures for corroded pipeline have been measured by burst testing and classified with respect to corrosion sizes and corroded regions — the body, the girth weld and the seam weld of pipe. Finite element analysis was carried out to derive failure criteria of corrosion defect within the body, the girth weld and the seam weld of the pipe. A series of finite element analyses were performed to obtain a limit load solution for corrosion defects on the basis of burst test. As a result, the criteria for failure assessment of corrosion defect within the body, the girth weld and the seam weld of API 5L X65 gas pipeline were proposed.

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