Compression Capacity and the Seismic Integrity of Locally Deformed Line Pipes

2018 ◽  
Author(s):  
Atsushi Suganuma ◽  
Junpei Kono ◽  
Masataka Hayashiguchi
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Strain Curve ◽  
Gas Pipeline ◽  
Earthquake Ground Motion ◽  
Finite Element Analyses ◽  
Compression Tests ◽  
Design Guideline ◽  
Line Pipe ◽  
Strain Capacity

This paper discusses the effects of local deformation, dent, and strain hardening properties on strain capacity in compression of a line pipe. Compression tests were conducted using two pipes with the nominal diameter of 400mm. These pipes had roundhouse type stress-strain curve, and correspond to L290 grade in Spec 5L of API (American Petroleum Institute) standards. One pipe was a plain pipe without dent, The other was a dented pipe. The depth of the dent was about 3% of the diameter. The test results explain that the strain capacity can be reduced by 25% due to the effect of dent. A series of finite element analyses were conducted to investigate the compression behaviors. The strain capacity in compression was defined as the longitudinal critical remote strain whose strain distribution was free from the effects of a dent. At first, that finite element analyses were verified that they could reproduce the results of compression tests. Next, the size of dent were changed on that finite element analyses model, some different case were analyzed in order to investigate the changes of the strain capacity in compression. The strain capacity, the longitudinal critical remote strain, decreased to about a half in case of 3%-depth dent, compared with a plain pipe. Seismic integrity of the pipeline with a dent is discussed in accordance with the seismic design guideline issued by Japan Gas Association. In case of the strong earthquake, “Ground Motion Level-1”, the dented gas pipeline is safe, even if the depth of the dent is 10% of the diameter. In case of the maximum earthquake, “Ground Motion Level-2”, the gas pipeline might buckle longitudinally in soft ground.

Design of Extended Pile Shafts for the Effects of Liquefaction

2014 ◽  
Vol 30 (4) ◽  
pp. 1775-1799 ◽  
Author(s):  
Arash Khosravifar ◽  
Ross W. Boulanger ◽  
Sashi K. Kunnath
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Ground Motion ◽  
Nonlinear Dynamic ◽  
Soil Structure ◽  
Lateral Spreading ◽  
Earthquake Loading ◽  
Finite Element Analyses ◽  
Dynamic Finite Element ◽  
Parametric Analyses

An equivalent static analysis (ESA) procedure is proposed for the design of extended pile shafts subjected to liquefaction-induced lateral spreading during earthquake loading. The responses of extended pile shafts for a range of soil, structure and ground motion conditions were examined parametrically using nonlinear dynamic finite element analyses (NDA). The results of those parametric analyses were used to develop and calibrate the proposed ESA procedure. The ESA procedure addresses both the nonliquefaction and liquefaction cases, and includes criteria that identify conditions which tend to produce excessive demands or collapse conditions. The ESA procedure, its limitations, and issues important for design are discussed.

Visual Image Correlation Compared to Discrete Instrumentation for Measurement of Compressive Strains for Strain Based Design

2017 ◽  
Author(s):  
Jason Bergman ◽  
Ming Liu ◽  
Chris Timms
Keyword(s):  
Finite Element ◽  
Direct Measurement ◽  
Strain Measurement ◽  
Measurement Techniques ◽  
Visual Image ◽  
Slope Instability ◽  
Image Correlation ◽  
Strain Gauges ◽  
Line Pipe ◽  
Strain Capacity

Strain-based design philosophies have been developed to ensure safe pipeline operation through regions of slope instability, seismic activity or discontinuous permafrost while extending the life expectancy of the pipeline in those zones. Strain-based design methodology typically involves a comparison of the strain demand (estimated conservatively using numerical pipe-soil interaction analysis techniques) to the strain capacity (predicted using experimentally benchmarked models). This paper presents a comparison of measurement techniques for laboratory testing of critical compressive strain capacity (CCS). The CCS is defined as the strain coinciding with the peak bending moment, averaged over a gauge length often selected as one pipe diameter across the buckle location. As explored in previous work [1], the three most common methods to measure strain on the specimen intrados, with respect to bending, include 1) direct measurement using strain gauges on the intrados with respect to bending, 2) calculation of CCS from the output of discrete instrumentation (DI) including strain gauges and inclinometers; and 3) direct measurement of surface strains using Visual Image Correlation (VIC) techniques. In 2015 and 2016, the Centre for Reliable Energy Systems (CRES) and C-FER Technologies 1999 Inc. (C-FER) collaborated on a series of full-scale experiments (performed by C-FER) and detailed finite element analysis (FEA) (performed by CRES) intended to assess and understand the effect of various anomalies on the strain capacity of line pipe. To facilitate comparison of the DI strain measurement method and the newer VIC method, these tests were conducted using both methods. The results demonstrate that the VIC technique can provide a more complete measure of the strain field and greater accuracy in cases where uneven strain distributions challenge the assumptions associated with DI methods. High level test data is presented and one test displaying the discrepancy between VIC and DI results is described. Finite element modelling, employed to explore the digression observed between the two strain measurement methods, is also presented and the comparative results of the two strain measurement techniques are discussed.

Effect of Material Stress-Strain Behavior and Pipe Geometry on the Deformability of High-Grade Pipelines

2004 ◽  
Vol 126 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Hiroshi Yatabe ◽  
Naoki Fukuda ◽  
Tomoki Masuda ◽  
Masao Toyoda
Keyword(s):  
Finite Element ◽  
High Grade ◽  
Finite Element Analyses ◽  
Analysis Method ◽  
Element Analysis ◽  
Line Pipe ◽  
Strain Behavior ◽  
Parametric Studies ◽  
Pipe Geometry ◽  
Strain Hardening Behavior

In this study, the deformability of high-grade pipelines subjected to an axial compressive deformation was experimentally and analytically discussed. Six cases of axial compression experiments with high-grade line pipe were carried out. The pipe specimens had various material properties and wall thickness. Finite-element analyses were also carried out and verified the reliability. Then, a finite-element analysis method for evaluating the deformability of the line pipe was established. By using this method, parametric studies were carried out. The effects of the strain-hardening behavior and pipe geometry on the deformability of the high-grade pipelines were examined.

Electrical Performance of Through-Silicon Vias (TSVs) for High-Frequency 3D IC Integration Applications

2012 ◽  
Vol 2012 (1) ◽  
pp. 001221-001228 ◽  
Author(s):  
Jui-Feng Hung ◽  
John H. Lau ◽  
Peng-Shu Chen ◽  
Shih-Hsien Wu ◽  
Sheng-Che Hung ◽  
...  
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
High Frequency ◽  
Electrical Performance ◽  
Finite Element Analyses ◽  
Design Guideline ◽  
3D Ic ◽  
Through Silicon Vias ◽  
Time Domains ◽  
Silicon Vias

In this study, the electrical performance of a general TSV structure for high-frequency 3D IC integration applications is investigated. Emphasis is placed on the proposal of an analytical model and the analytical equations of a TSV with all its key parameters. Also, the model and equations are verified, both in the frequency and time domains, by more detailed finite element analyses. Finally, a TSV electrical design guideline is proposed.

scholarly journals Contribution of finite element analyses to crack-like flaw assessments in a gas pipeline

2018 ◽  
Vol 161 ◽  
pp. 41-49 ◽  
Author(s):  
Thibault Jacquemin ◽  
Mehmet E. Kartal ◽  
Gonzague Du Suau ◽  
Stéphane Hertz-Clémens
Keyword(s):  
Finite Element ◽  
Gas Pipeline ◽  
Finite Element Analyses

Compressive Strain Limit of Aged API-X100 Linepipe

2009 ◽  
Author(s):  
Woo Yeon Cho ◽  
Dong-Han Seo ◽  
Jang-Yong Yoo
Keyword(s):  
Finite Element ◽  
Yield Point ◽  
Numerical Solutions ◽  
Numerical Models ◽  
Compressive Strain ◽  
Local Buckling ◽  
Strain Curve ◽  
Element Model ◽  
Stress Strain ◽  
Strain Capacity

In compressive strain capacity, high deformable linepipe steel, which is able to delay or evade local buckling, is needed. The objective of this paper is to present the results of an experimental and a finite-element investigation into the behavior of pipes subjected to bending behavior of aged API-X100 linepipe. The comparative behavior of aged and non aged specimens was recorded. The Results from numerical models are checked against the observations in the testing program and the ability of numerical solutions to predict pipe compressive strain capacity, curvatures, and buckling modes is improved. A finite-element model was developed using the finite-element simulator ABAQUS to predict the local buckling behavior of pipes. The input stress-strain relations of the material were discussed using the indexed yield point elongations. The comparison between the results of yield point elongation type material and those of material of smooth stress-strain curve near yield was done.

scholarly journals Collapse Analysis of Transmission Tower Subjected to Earthquake Ground Motion

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Xiaohong Long ◽  
Wei Wang ◽  
Jian Fan
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Particle Method ◽  
Earthquake Ground Motion ◽  
Particle Model ◽  
Variation Principle ◽  
Transmission Tower ◽  
Seismic Safety ◽  
Dynamic Nonlinearity ◽  
Finite Particle

The collapse of transmission towers involves a series of complex problems, including geometric nonlinearity, material nonlinearity, dynamic nonlinearity, and the failure of members. Simulation of the process of collapse is difficult using traditional finite element method (FEM), which is generated from continuum and variation principle, whereas the finite particle method (FPM) enforces equilibrium on each point. Particles are free to separate from one another, which is advantageous in the simulation of the structural collapse. This paper employs the finite particle method (FPM) to simulate the collapse of a transmission steel tower under earthquake ground motions; the three-dimensional (3D) finite particle model using MATLAB and the 3D finite element model using ANSYS of the transmission steel tower are established, respectively. And the static and elastic seismic response analyses indicate that the results of the FPM agree well with those of the FEM. To simulate the collapse of the transmission steel tower, a failure criterion based on the ideal elastic-plastic model and a failure mode are proposed. Finally, the collapse simulation of the transmission steel towers subjected to unidirectional earthquake ground motion and the collapse seismic fragility analysis can be successfully carried out using the finite particle method. The result indicates that the transmission steel tower has better seismic safety performance and anticollapse ability.

Seismic Integrity of High-Strain Cold Bend in Lateral Spreading Zone

2014 ◽  
Author(s):  
Nobuhisa Suzuki ◽  
Hidetaka Watanabe ◽  
Toshiyuki Mayumi ◽  
Hiroyuki Horikawa
Keyword(s):  
Residual Strain ◽  
High Strain ◽  
Peak Load ◽  
Local Buckling ◽  
Strain Curve ◽  
Lateral Spreading ◽  
Line Pipe ◽  
Strain Capacity ◽  
Cold Bending ◽  
Opening Mode

Excellent workability of the stress-strain curve controlled high strain line pipe on cold bending with a bending angle of 10 degrees is presented. The high-strain line pipe has a round-house type s-s curve with the stress ratio σ2.0/σ1.0 of 1.030, where σ1.0 and σ2.0 are 1.0% and 2.0% yield stress, respectively. A standard yield-plateau type line pipe was also employed for comparison. FEA was conducted to investigate the cold bending behaviors of X65, 24″ line pipe. The longitudinal strain induced in the high-strain pipe at peak load and unloaded steps are small compared to those in the standard pipe. Effects of residual strain on local buckling behaviors of the high-strain cold bends are investigated. The effect of residual strain on the strain capacity of cold bend subjected to closing and opening mode bending is small when the cold bend is not pressurized. FEA tends to overestimate the strain capacity in bending when the bend is pressurized. However FEA well predicts the locations of the shell wrinkle of the pressurized bend subjected to opening mode bending when residual strain is taken into account. Seismic integrity of the 24″ high-strain cold bend in a lateral spreading zone is demonstrated.

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