Effects of Stress–Strain Characteristics on Local Buckling of X80 Pipe Subjected to Strike-Slip Fault Movement

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Xiaoben Liu ◽  
Hong Zhang ◽  
Onyekachi Ndubuaku ◽  
Mengying Xia ◽  
J. J. Roger Cheng ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Local Buckling ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Large Strains ◽  
Fe Model ◽  
Stress Strain ◽  
Shell Elements ◽  
Steel Material ◽  
Buckling Behavior

The structural integrity of underground pipelines are subject to a major threat from permanent ground displacements when they cross active tectonic (e.g., strike-slip) faults, because of large strains potentially induced in pipes, leading to pipe buckling and possible rupture. In this paper, the buckling behavior of X80 pipe is studied numerically with an emphasis on the effects of steel stress–strain characteristics. A rigorous mechanics-based nonlinear finite element (FE) model of a buried X80 pipe crossing a strike-slip fault is developed using shell elements and nonlinear springs for the pipe and soil resistance, respectively. The pipe steel material in the FE model is characterized by a novel and versatile stress–strain relationship, which was established to successfully capture both the round-house (RH) type and the yield-plateau (YP) type stress–strain behaviors. This allows investigating the significant effects of the stress–strain characteristics, as observed in this paper, on the buckling behavior of pressurized and nonpressurized pipes.

scholarly journals Local Buckling Behavior and Plastic Deformation Capacity of High-Strength Pipe at Strike-Slip Fault Crossing

Metals ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 22 ◽  
Author(s):  
Xiaoben Liu ◽  
Hong Zhang ◽  
Baodong Wang ◽  
Mengying Xia ◽  
Kai Wu ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Local Buckling ◽  
High Strength ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Deformation Capacity ◽  
Buckling Behavior

Buckling Behavior of Buried High Strength Steel Pipeline Under Compression Strike-Slip Fault Movement

2017 ◽  
Author(s):  
Xiaoben Liu ◽  
Hong Zhang ◽  
Mengying Xia ◽  
Meng Li
Keyword(s):  
Local Buckling ◽  
High Strength ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Ground Movement ◽  
Pipe Failure ◽  
Axial Section ◽  
Buckling Behavior ◽  
Fault Displacement ◽  
Critical Fault

Active fault is the most dangerous natural hazards of buried steel pipelines, as large stress and strain induced by ground movement can lead to pipe failure, which may cause severe accidents. Based on nonlinear finite element method, local buckling behavior of buried high strength X80 steel pipelines under compression strike-slip fault was studied systematically. Accuracy of the numerical model was validated by previous full scale experimental results. A baseline analysis was performed to elucidate the local buckling phenomenon of pipe. Parametric analysis was also performed to investigate the effects of influence factors of pipe’s buckling behavior. Results shows that, when local buckling occurs, axial section force decreases abruptly. When pipe-fault intersection angle equals 135°, the maximum axial section force peaks and the critical fault displacement is the smallest. With the increase of pipe wall thickness, the maximum axial section force and the critical fault displacement increases. With the increase of pipe internal pressure, the maximum axial section force and the critical fault displacement decreases. When p = 0MPa, inward-diamond buckling occurs in the pipe. While p≥4MPa, elephant-foot buckling occurs in the pipe.

Experimental and Numerical Investigation Into the Behavior of Buried Steel Pipelines Under Strike-Slip Fault Movement

2016 ◽  
Author(s):  
Sjors H. J. van Es ◽  
Arnold M. Gresnigt
Keyword(s):  
Numerical Model ◽  
Local Buckling ◽  
Computation Time ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Soil Conditions ◽  
Test Results ◽  
Fault Movement ◽  
Nonlinear Springs ◽  
Deformational Behavior

Buried steel pipelines for water and hydrocarbon transmission in seismic regions may be subjected to large imposed deformations. When a buried pipeline crosses an active strike-slip fault, the relative motion of the two soil bodies in which is it embedded can lead to significant deformation of the pipeline and possibly to loss of containment. To be able to fully understand the effects of this movement and the interaction between pipe and soil on the strain demands in the pipeline, a novel full scale experimental setup has been developed. To allow accurate monitoring of the pipeline deformation, the pipe-surrounding soil has been replaced with appropriate nonlinear springs, leaving the pipe bare during the experiment. In a total of ten tests, the strain demand in a pipeline as a result of these ground-induced deformations has been investigated. The testing program includes variations of pipeline geometry, steel grade and internal pressure. Furthermore, cohesive and non-cohesive soils have been simulated in the tests. Observed responses of the pipeline include local buckling, high tensile strains (up to 5%) and, in one case, cracking of the pipeline. Based on experiences with these experiments, a numerical model has been developed that uses non-linear springs to model the pipe-soil interaction. By modelling the pipe and soil conditions that were simulated in the ten experiments, this model has been calibrated and validated. Comparisons between the model predictions and test results show that the numerical model is able to predict the deformational behavior of the pipeline accurately. Moreover, also the formation of local buckles is predicted with satisfying results. The results of the validation operation lead to the conclusion that the new model is performing well. By omitting the modelling of the full soil body, computation time is reduced, increasing practical use of the developed model.

Designing Hierarchical IsoTruss Column Based on Controlling Multi-Buckling Behaviors

2021 ◽  
Author(s):  
Changliang Lai ◽  
Qianqian Sui ◽  
Hualin Fan
Keyword(s):  
Finite Element ◽  
Parametric Design ◽  
Local Buckling ◽  
Fe Model ◽  
The Finite Element Method ◽  
Buckling Modes ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Buckling Failure ◽  
Theoretical Analyses

To develop large-span but ultralight lattice truss columns, a hierarchical IsoTruss column (HITC) was proposed. The multi-buckling behavior of the axially compressed HITC was analyzed by the finite element method (FEM) using a parametric approach in the framework of ANSYS parametric design language (APDL). It was demonstrated that the program enables efficient generation of the finite element (FE) model, while facilitating the parametric design of the HITC. Using this program, the effects of helical angles and brace angles on the buckling behavior of the HITC were investigated. Depending on the helical angles and brace angles, the HITCs mainly have three buckling modes: the global buckling, the first-order local buckling and the second-order local buckling. Theoretical multi-buckling models were established to predict the critical buckling loads. Buckling failure maps based on the theoretical analyses were also developed, which can be useful in preliminary design of such structures.

Structural Performance of Buried Steel Pipelines Crossing Strike-Slip Faults

2014 ◽  
Author(s):  
Polynikis Vazouras ◽  
Panos Dakoulas ◽  
Spyros A. Karamanos
Keyword(s):  
Closed Form ◽  
Local Buckling ◽  
Closed Form Solution ◽  
Strike Slip ◽  
Form Solution ◽  
Strike Slip Fault ◽  
Performance Criteria ◽  
Cross Sectional ◽  
Soil System ◽  
Inelastic Material

The performance of pipelines subjected to permanent strike-slip fault movement is investigated by combining detailed numerical simulations and closed-form solutions. A closed-form solution for the force-displacement relationship of a buried pipeline subjected to tension is presented and used in the form of nonlinear springs at the two ends of the pipeline in a refined finite element model, allowing an efficient nonlinear analysis of the pipe-soil system at large strike-slip fault movements. The analysis accounts for large deformations, inelastic material behaviour of the pipeline and the surrounding soil, as well as contact and friction conditions on the soil-pipe interface. Appropriate performance criteria of the steel pipeline are adopted and monitored throughout the analysis. It is shown that the end conditions of the pipeline have a significant influence on pipeline performance. For a strike-slip fault normal to the pipeline axis, local buckling occurs at relatively small fault displacements. As the angle between the fault normal and the pipeline axis increases, local buckling can be avoided due to longitudinal stretching, but the pipeline may fail due to excessive axial tensile strains or cross sectional flattening.

Mechanical Behavior of Buried Steel Pipelines Crossing Strike-Slip Seismic Faults

2011 ◽  
Author(s):  
Polynikis Vazouras ◽  
Spyros A. Karamanos ◽  
Panos Dakoulas
Keyword(s):  
Mechanical Response ◽  
Pipe Wall ◽  
Active Faults ◽  
Local Buckling ◽  
Strike Slip ◽  
Nonlinear Material ◽  
Graphical Form ◽  
Large Strains ◽  
Pipeline System ◽  
Fault Displacement

The present paper investigates the mechanical behaviour of buried steel pipelines, crossing active strike-slip tectonic faults. The fault plane is vertical and perpendicular to the pipeline axis. The interacting soil-pipeline system is modelled rigorously through finite elements, which account for large strains and displacements, nonlinear material behaviour and special conditions of contact and friction on the soil-pipe interface. Steel pipelines of various diameter-to-thickness ratios, and typical steel material for pipeline applications (API 5L grades X65 and X80) are considered. The paper investigates the effects of various soil and pipeline parameters on the mechanical response of the pipeline, with particular emphasis on pipe wall failure due to “local buckling” or “kinking” and pipe wall rupture. The effects of shear soil strength and stiffness, are also investigated. Furthermore, the influence of the presence of pipeline internal pressure on the mechanical response of the steel pipeline is examined. Numerical results aim at determining the fault displacement at which the pipeline failure occurs, and they are presented in a graphical form that shows the critical fault displacement, the corresponding critical strain versus the pipe diameter-to-thickness ratio. It is expected that the results of the present study can be used for efficient pipeline design in cases where active faults are expected to impose significant ground-induced deformation to the pipeline.

Strain Prediction for X80 Steel Pipeline Subjected to Strike-Slip Fault Under Compression Combined With Bending

2015 ◽  
Author(s):  
Xiaoben Liu ◽  
Hong Zhang ◽  
Yanfei Chen
Keyword(s):  
Compressive Strain ◽  
Strike Slip ◽  
Numerical Results ◽  
Strike Slip Fault ◽  
Fe Model ◽  
Long Distance ◽  
Steel Pipeline ◽  
Reliability Based Design ◽  
Applicable Range ◽  
X80 Steel

Strike-slip fault is one main kind of PGD faced by long distance gas pipelines. Based on non-linear finite element method, a numerical model for buried pipeline under strike-slip fault was proposed. The model was proven to be reasonable by comparing the numerical results with previous researcher’s experiment results. By using the FE model, peak compressive strain of X80 steel pipeline subjected to strike-slip fault under compression combined with bending was studied. The sensitivities of the diameter, wall thickness, soil rigidity, fault displacement and crossing angle on the peak compressive strain of the pipeline are examined in detail. Furthermore, based on numerous numerical results, a regression equation for predicting peak compressive strain of X80 steel pipeline is proposed. The applicable range of the formula is given. 15 true design cases in the Second West to East pipeline Project in China were investigated to demonstrate the accuracy and applicability of the proposed methodology by comparing the predicting peak compressive strain results with FEM results. The proposed method can be referred in the strain-based and reliability-based design for X80 steel pipelines subjected to strike-slip fault.

Local Buckling Behavior of X100 Linepipes

2003 ◽  
Author(s):  
Nobuhisa Suzuki ◽  
Ryuji Muraoka ◽  
Alan Glover ◽  
Joe Zhou ◽  
Masao Toyoda
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
Critical Strain ◽  
Axial Stress ◽  
Local Buckling ◽  
Bending Moment ◽  
Finite Element Analyses ◽  
Design Factor ◽  
Shell Elements ◽  
Buckling Behavior

Local buckling behavior of API 5L X100 grade linepipes subjected to axial compression and/or bending moment is discussed in this paper based on results obtained by finite element analyses. Yield-to-tensile strength (Y/T) ratio and design factor were taken into account in the finite element analyses in order to discuss their effects on the local buckling behavior. The local bucking behavior of such lower strength linepipes as X60 and X80 grade linepipes is also discussed for comparison. Two-dimensional solid elements and four-node shell elements were used for the finite element modeling of the linepipes subjected to axial compression and bending moment, respectively. The study has improved the understanding of local buckling behavior of the X100 grade linepipes and observed the following trends. When a linepipe is subjected to axial compression, the critical axial stress decreases with increasing design factor and Y/T ratio. However, the nominal critical strain increases with increasing design factor and decreasing Y/T ratio. When a linepipe is subjected to bending moment, the critical bending moment decreases with increasing design factor and Y/T ratio. Similarly, the nominal critical strain increases with increasing design factor. However, the nominal critical strain increases with decreasing Y/T ratio when the design factor is less than and equal to 0.6 and decreases with decreasing Y/T ratio when the design factor is equal to 0.8.

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