Influence of Geotechnical Loads on Local Buckling Behavior of Buried Pipelines

2008 ◽  
Author(s):  
Hiva Mahdavi ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Local Buckling ◽  
Small Diameter ◽  
Ground Movement ◽  
Combined Loading ◽  
Fe Model ◽  
Buried Pipelines ◽  
Limit States

Buried pipelines can be subjected to differential ground movement events. The ground displacement field imposes geotechnical loads on the buried pipeline and may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. The conventional engineering approach to define the mechanical performance of pipelines has been based on combined loading events for “in-air” conditions. This methodology is assumed to be overly conservative and ignores soil effects that imposes geotechnical loads and also provides restraint, on buried pipelines. The importance of pipeline/soil interaction and load transfer mechanisms that may affect local buckling of buried pipelines is not well understood. In this study a three-dimensional continuum finite element (FE) model, using the software package ABAQUS/Standard, was developed and calibrated based on large-scale tests on the local buckling of linepipe segments for in-air and buried conditions. The effects of geotechnical boundary conditions on pipeline deformation mechanism and load carrying capacity were examined for a single small diameter pipeline with average diameter to thickness ratio and deep buried condition. The calibrated model successfully reproduced the large-scale buried test results in terms of the local buckling location, pipeline carrying load capacity, soil deformation and soil failure mechanism.

scholarly journals Significance of geotechnical loads on local buckling response of buried pipelines with respect to conventional practice

2013 ◽  
Vol 50 (1) ◽  
pp. 68-80 ◽  
Author(s):  
Hiva Mahdavi ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Load Transfer ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Local Buckling ◽  
Element Model ◽  
Combined Loading ◽  
Buried Pipelines ◽  
Buried Pipe ◽  
Limit States ◽  
New Criterion

Long-term large deformation geohazards can impose excessive deformation on a buried pipeline. The ground displacement field may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. The conventional engineering approach to define the mechanical performance of pipelines has been based on combined loading events for in-air conditions. This methodology may be conservative, as it ignores the soil effect that imposes geotechnical loads, and also provides restraint, on buried pipelines. The importance of pipeline–soil interaction and load-transfer mechanisms that may affect local buckling of buried pipelines is not well understood. A three-dimensional continuum finite element model, simulating the local buckling response of a buried pipe, using the software package ABAQUS/Standard was developed and calibrated. A comprehensive parametric study was previously conducted to investigate the effect of several parameters on local buckling response of pipelines buried in firm clay. A new strain criterion for local buckling of buried pipelines in firm clay through response surface methodology was developed. In this paper, the new criterion is compared with several existing in-air criteria to study the effect of soil restraint on the local buckling response of buried pipelines. The criterion developed in this study predicts greater characteristic critical strain capacity than in-air based criteria that highlights the influence of soil restraint.

Ductile iron pipeline response to earthquake-induced ground rupture

2020 ◽  
Vol 36 (2) ◽  
pp. 832-855
Author(s):  
Christina Argyrou ◽  
Thomas D O’Rourke ◽  
Chalermpat Pariya-Ekkasut ◽  
Harry E Stewart
Keyword(s):  
Ductile Iron ◽  
Large Scale ◽  
Comprehensive Evaluation ◽  
Ground Deformation ◽  
Local Buckling ◽  
Fe Model ◽  
Limit States ◽  
Pullout Resistance ◽  
Earthquake Performance ◽  
Dimensional Finite Element

This article provides a comprehensive evaluation of ductile iron (DI) pipeline response to earthquake-induced ground deformation through the results of a large-scale testing program and a fault rupture test on a 150-mm DI pipeline with restrained axial slip joints. The test is used to validate a two-dimensional finite element (FE) model that accounts for soil–pipeline interaction with axial slip, pullout resistance, and rotation of pipe joints. The maximum strike-slip fault offset sustained by push-on, restrained, and restrained axial slip joints is presented as a function of the pipeline/fault crossing angle. DI pipeline performance is controlled by one of the following limit states; tensile, compressive, rotational joint capacity, or local buckling in the pipe barrel. A systematic FE assessment shows that pipelines with restrained axial slip joints accommodate 2–9 and 2–10 times as much fault offset as pipelines with push-on and restrained joints, respectively, for most intersection angles. The results of this work can be used for simplified design and to quantify the relative earthquake performance of different DI pipelines.

Limit Load Capacity of Thick-Walled Pipe Loaded by Internal Pressure and Bending

2021 ◽  
Author(s):  
Ruud Selker ◽  
Joost Brugmans ◽  
Ping Liu ◽  
Carlos Sicilia
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Load Capacity ◽  
Limit State ◽  
Local Buckling ◽  
Limit Load ◽  
Combined Loading ◽  
Fe Model ◽  
State Equations

Abstract Internally pressurised pipe behaves differently than externally pressurised pipe. DNVGL-ST-F101 [4], a prevailing standard for the design of submarine pipelines, provides limit-state equations for combined loading that are valid only if the diameter-to-wall-thickness ratio (D/t) is between 15 and 45. A recent study has shown that the results are increasingly conservative for lower values of this ratio if the nett pressure is acting on the pipe’s outside [8], especially if it is below 20. In this paper, the applicability of the limit-state equations for thick-walled pipe with D/t less than 15 and loaded by a nett internal pressure has been investigated. The first step was a fundamental review of the formulations. Next, the predicted capacities were compared with those estimated using a finite-element (FE) model. The results greatly coincided, which indicates that the conservatism underlying the formulations does not depend on D/t. Hence they can be used for design against local buckling under internal overpressure, too, when the ratio is below 15.

Effect of Soil Restraint on the Buckling Response of Buried Pipelines

2010 ◽  
Author(s):  
Hiva Mahdavi ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Critical Strain ◽  
Mechanical Response ◽  
Ground Deformation ◽  
Compressive Strain ◽  
Local Buckling ◽  
Engineering Practice ◽  
Buried Pipelines ◽  
Limit States ◽  
Axial Thrust ◽  
New Criterion

Long-term large deformation geohazards can impose excessive deformation on a buried pipeline. The ground displacement field may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. Conventional engineering practice to define the peak moment or compressive strain limits for buried pipelines has been based on the pipeline mechanical response for in-air conditions. This methodology may be conservative as it ignores the soil effect that imposes geotechnical loads and restraint on buried pipelines. The importance of pipeline/soil interaction and load transfer mechanisms that may affect local buckling of buried pipelines is not well understood. The authors previously developed a new criterion for local buckling strain of buried pipelines in stiff clay through response surface methodology (RSM) [1, 2]. In this paper the new criterion was compared with a number of available in-air based criteria to study the effect of soil restraint on local buckling response of buried pipelines. This criterion predicted larger critical strain than selected in-air based criteria which shows the significant influence of soil presence. The supportive soil effect is discussed. The soil restraining effect increases the pipeline bending resistance, when the pipeline is subjected to large displacement-controlled ground deformation. A correlation between Palmer’s et al. (1990) conclusion [3] and current study’s results has been made. The critical strain increases as the ratio between axial thrust and pipeline bending stiffness decreases.

Upheaval Buckling of Small Diameter Pipelines Induced by Strong Ground Shaking

2012 ◽  
Author(s):  
Hiroyuki Horikawa ◽  
Yoji Tsunasawa ◽  
Hajime Shinkai ◽  
Nobuhisa Suzuki
Keyword(s):  
Local Buckling ◽  
Small Diameter ◽  
Field Tests ◽  
Bending Moment ◽  
Design Guidelines ◽  
Combined Loading ◽  
Pipe Material ◽  
Effective Parameters ◽  
Ground Shaking ◽  
Upheaval Buckling

Upheaval buckling of small diameter gas pipeline occurred due to strong seismic excitation during the 2007 Niigata-ken Chuetsu-Oki earthquake whose diameters were 4″ and smaller. This paper deals with investigation of the upheaval buckling of gas pipes conducted by Ministry of Economy, Trade and Industry of Japan to establish seismic design guidelines to mitigate upheaval buckling. Sand box and field tests were conducted using small diameter pipes to simulate the upheaval buckling behaviors and construct a simple finite element model. The results clarified that the tensile properties of pipe material and pipe-soil interaction were the most effective parameters to explain the buckling behaviors. Interaction curve of pipes can be found in the relationship between compression and bending moment in the combined loading tests. The deformation behaviors of the buried pipe tests followed the interaction curve and local buckling of buried pipes occurred in lower bending moment than that of pipes not buried.

Parameters Affecting the Local Buckling Response of High Strength Linepipe

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Ali Fatemi ◽  
Shawn Kenny
Keyword(s):  
Yield Strength ◽  
Large Scale ◽  
Mechanical Response ◽  
Local Buckling ◽  
High Strength ◽  
Combined Loading ◽  
Parameter Study ◽  
Model Parameters ◽  
Pipe Length ◽  
Numerical Predictions

The local buckling response and post-buckling mechanical performance of high strength linepipe subject to combined loading state was evaluated using the finite element (FE) simulator abaqus/standard v6.12. The constitutive model parameters were established through laboratory tests and the numerical modeling procedures were verified with large-scale experiments investigating the local buckling response of high strength linepipe. The numerical predictions demonstrated a high level of consistency and correspondence with the measured experimental behavior with respect to the peak moment, strain capacity, deformation mechanism, and local buckling response well into the postyield range. A parametric study on the local buckling response of high strength plain and girth weld pipelines was conducted. The loading conditions included internal pressure and end rotation. The pipe mechanical response parameters examined included moment–curvature, ovalization, local strain, and modal response. The magnitude and distribution of the characteristic geometric imperfections and the end constraint, associated with the boundary conditions and pipe length, had a significant influence on the predicted local buckling response. The importance of material parameters on the local buckling response, including the yield strength (YS), yield strength to tensile strength ratio (Y/T), and anisotropy, was also established through the numerical parameter study. For girth weld linepipe, the study demonstrated the importance of the local high/low misalignment, associated with the circumferential girth weld, on the local buckling response.

Scalable production of ultrafine polyaniline fibres for tactile organic electrochemical transistors

2021 ◽  
Author(s):  
Bo Fang ◽  
Jianmin Yan ◽  
Dan Chang ◽  
Jinli Piao ◽  
Kit Ming Ma ◽  
...  
Keyword(s):  
Conducting Polymer ◽  
Large Scale ◽  
Mechanical Performance ◽  
Small Diameter ◽  
High Energy ◽  
Drawing Ratio ◽  
Driving Voltage ◽  
Large Area ◽  
Friction Forces ◽  
Electrochemical Transistor

Abstract The development of continuous conducting polymer fibres is essential for applications ranging from advanced fibrous devices to frontier fabric electronics. The use of continuous conducting polymer fibres requires a small diameter to maximize their electroactive surfaces, microstructural orientations, and mechanical strengths. However, regularly used wet spinning techniques have rarely achieved this goal due primarily to the insufficient slenderization of rapidly solidified conducting polymer molecules in poor solvents. Here we report a good solvent exchange strategy to wet spin the ultrafine polyaniline fibres at the large scale. The slow diffusion between good solvents distinctly decreases the viscosity of gel protofibers, which undergo an impressive drawing ratio. The continuously collected polyaniline fibres have a previously unattained diameter below 5 µm, high energy and charge storage capacities, and favorable mechanical performance. We demonstrated an ultrathin all-solid organic electrochemical transistor based on ultrafine polyaniline fibres, which substantially amplified microampere drain-source electrical signals with less one volt driving voltage and effectively operated as a tactile sensor detecting pressure and friction forces at different levels. The aggressive electronical and electrochemical merits of ultrafine polyaniline fibres and their great potentials to prepare on industrial scale offer new opportunities for high-performance soft electronics and large-area electronic textiles.

Strain Capacity of X100 High-Strain Linepipe for Strain-Based Design Application

2008 ◽  
Author(s):  
Satoshi Igi ◽  
Joe Kondo ◽  
Nobuhisa Suzuki ◽  
Joe Zhou ◽  
Da-Ming Duan
Keyword(s):  
Tensile Strain ◽  
Large Scale ◽  
High Strain ◽  
Compressive Strain ◽  
Local Buckling ◽  
Ground Movement ◽  
Frozen Ground ◽  
Long Distance ◽  
Element Analysis ◽  
Strain Capacity

In recent years, several natural gas pipeline projects have been planned for permafrost regions. Pipelines laid in such areas are subjected to large plastic deformation as a result of ground movement due to repeated thawing and freezing of the frozen ground. Likewise, in pipeline design methods, research on application of strain-based design as an alternative to the conventional stress-based design method has begun. Much effort has been devoted to the application of strain-based design to high strength linepipe materials. In order to verify the applicability of high-strain X100 linepipe to long distance transmission, a large-scale X100 pipeline was constructed using linepipe with an OD of 42″ and wall thickness of 14.3mm. This paper presents the results of experiments and Finite Element Analysis (FEA) focusing on the strain capacity of high-strain X100 linepipes. The critical compressive strain of X100 high-strain linepipes is discussed based on the results of FEA taking into account geometric imperfections. The critical tensile strain for high-strain X100 pipelines is obtained based on a curved wide plate (CWP) tensile test using specimens taken from girth welded joints. Specifically, the effect of external coating treatment on the strain capacity of X100 high-strain linepipe is investigated. The strain capacity of the 42″ X100 pipeline is considered by comparing the tensile strain limit obtained from girth weld fracture and critical compressive strain which occurs in local buckling under pure bending deformation.

Efficient Schedule of Energy-Constrained UAV Using Crowdsourced Buses in Last-Mile Parcel Delivery

2021 ◽  
Vol 5 (1) ◽  
pp. 1-23
Author(s):  
Yan Pan ◽  
Shining Li ◽  
Qianwu Chen ◽  
Nan Zhang ◽  
Tao Cheng ◽  
...  
Keyword(s):  
Traffic Congestion ◽  
Large Scale ◽  
Load Capacity ◽  
Scheduling Algorithm ◽  
Cost Effective ◽  
Promising Alternative ◽  
Logistics Industry ◽  
Last Mile ◽  
Delivery Scheduling ◽  
Schedule Approach

Stimulated by the dramatical service demand in the logistics industry, logistics trucks employed in last-mile parcel delivery bring critical public concerns, such as heavy cost burden, traffic congestion and air pollution. Unmanned Aerial Vehicles (UAVs) are a promising alternative tool in last-mile delivery, which is however limited by insufficient flight range and load capacity. This paper presents an innovative energy-limited logistics UAV schedule approach using crowdsourced buses. Specifically, when one UAV delivers a parcel, it first lands on a crowdsourced social bus to parcel destination, gets recharged by the wireless recharger deployed on the bus, and then flies from the bus to the parcel destination. This novel approach not only increases the delivery range and load capacity of battery-limited UAVs, but is also much more cost-effective and environment-friendly than traditional methods. New challenges therefore emerge as the buses with spatiotemporal mobility become the bottleneck during delivery. By landing on buses, an Energy-Neutral Flight Principle and a delivery scheduling algorithm are proposed for the UAVs. Using the Energy-Neutral Flight Principle, each UAV can plan a flying path without depleting energy given buses with uncertain velocities. Besides, the delivery scheduling algorithm optimizes the delivery time and number of delivered parcels given warehouse location, logistics UAVs, parcel locations and buses. Comprehensive evaluations using a large-scale bus dataset demonstrate the superiority of the innovative logistics UAV schedule approach.

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