Xiaoben Liu

China University of Petroleum - Beijing | CUPB · Oil & Gas Storage and Transportation Engineering

The reverse fault is one of main threats faced by high strength gas pipelines, for the potential of leading to buckling failure in the pipe. A 3D finite element model was established in this study, in which the pipe was modeled by shell elements and the pipe-soil interaction relationship by spring elements. A suitable equivalent boundary condition...

The reverse fault is a dangerous geological hazard faced by buried steel pipelines. Permanent ground deformation along the fault trace will induce large compressive strain leading to buckling failure of the pipe. A hybrid pipe-shell element based numerical model programed by INP code supported by ABAQUS solver was proposed in this study to explore...

Stress concentration during the operation of long-distance transmission pipelines is an inevitable problem. In this paper, a pipeline stress detection method based on vibration characteristics is proposed. We establish a finite element model for knock detection and determine the law of vibration frequency and pipeline stress. The reliability of the...

The strain identification technology based on inertial mapping unit (IMU) internal detectors is currently a widely used internal detection technology for identifying pipeline bending strain both domestically and internationally. It calculates the bending strain of the entire pipeline through the detected centerline coordinate data. However, there a...

As a typical welding structure, the girth weld of high-grade pipelines has obvious heterogeneity. Therefore, the axial mechanical properties of girth weld materials cannot be accurately tested, and the safety evaluation of the girth weld of the pipeline is seriously affected. Based on MATLAB-PYTHON-ABAQUS co-simulation, an optimization inversion me...

In recent years, the safety of oil and gas pipelines has become a primary concern for the pipeline industry. This paper presents a comprehensive study of the vulnerability concepts that may be used to measure the safety status of pipeline systems. The origins of the vulnerability concepts are identified, the development and evolution of the vulnera...

In this study, a methodology to evaluate and predict the vulnerability of the natural gas supply chain is proposed, and both the dynamics and stochasticity of the natural gas supply chain are considered. In the methodology, the evaluation system of the vulnerability is established firstly based on the definition of the vulnerability of the natural...

Long-distance oil and gas pipelines buried in permafrost areas will inevitably encounter typical geological disasters, such as frost heave and thaw settlement and sliding, which easily cause pipeline displacement, bending, or deformation. When there are certain defects in the pipeline, additional complex, external stress will further lead to the fa...

As a typical welding structure, the girth weld of high-grade pipelines has obvious heterogeneity. Therefore, the axial mechanical properties of girth weld materials cannot be accurately tested, and the safety evaluation of the girth weld of the pipeline is seriously affected. Based on MATLAB-PYTHON-ABAQUS co-simulation, an optimization inversion me...

External corrosion dent is a common type of compound dent. On the one hand, this type of compound dent reduces the bearing area and bearing capacity of the pipeline. On the other hand, it leads to an increase in the stress–strain concentration in the dent and reduces the anti-fatigue load capacity of the pipeline, which is more harmful to the servi...

Crack defects in mitred bends seriously affect the structural safety of steel pipelines. Therefore, particular attention should be paid to fracture failure of mitred bends due to stress concentration and formation of defects. In this paper, the fracture response of mitred butt girth weld pipeline with crack defect was investigated by conducting ful...

The acceleration of global urbanization and an increasing intersection of roads and buried pipelines pose a certain threat to the operation safety of pipelines. In this paper, the mechanical response of the X65 pipeline under empty-load, half-load, and full-load traffic loads is investigated via field experiments. The numerical model considering th...

Crack defects in the girth welds of pipelines have become an important factor affecting the safe operation of in-service oil pipelines. Therefore, it is necessary to analyze the factors affecting the safe operation of pipelines and determine the ultimate load during pipeline operation. Based on the failure assessment diagram (FAD) method described...

At present, the artificial recognition method is mainly used to identify IMU strain detection data of the whole pipe section by segment, which has some problems such as low efficiency, high cost and long cycle. Therefore, this paper realizes the intelligent recognition of the Bending Deformed Section in Geological Disaster Area (BDPIGDA) by establi...

With the advances in material research and pipe manufacturing, the construction of oil and gas pipelines is developing continuously, and the evaluation of welding joints with defects has become the focus of pipeline safety research. In this study, two full-scale wide plate tensile tests were performed on Ø1422 mm × 25.7 mm X80 specimens with origin...

With continued urbanization in China, the construction of urban gas pipelines is increasing, and the safety of gas pipelines are also increasingly affected by urban development and the increased scope of buildings and roads. Pipes with defects are more likely to fail under the surface loads. In this study, uniaxial tensile tests of high-density pol...

Reinforced thermoplastic pipes (RTP) are widely used in the offshore oil and gas production industry for their excellent flexibility, corrosion resistance and internal pressure resistance. RTPs inevitably experience extreme environmental loads including internal pressure and tensile load in the procedures of installation and operation, which influe...

Thawing landslide is a common geological disaster in permafrost regions, which seriously threatens the structural safety of oil and gas pipelines crossing permafrost regions. Most of the analytical methods have been used to calculate the longitudinal stress of buried pipelines. These analytical methods are subjected to slope-thaw slumping load, and...

Crack-like defects frequently form in pipes exposed to aggressive environments or during welding fabrication. Appropriate strength matching factors should be determined for welding process evaluation based on the reliability aspect. In this paper, the current research status of codes and standards related to the strength requirement of weld metals...

A pipeline inspection gauge (PIG) is routinely passed throughout the long‐distance oil and gas pipelines by pipeline operators to clean the pipeline. Sealing performance is a significant evaluation index for PIG's safety operation. To comprehensively evaluate the PIG's seal performance, nonlinear finite element models were developed, and parametric...

Strength mismatched pipes with part-through cracks can suffer large plastic deformation from permanent ground deformations caused by geohazards. Thus, the crack driving force involved in engineering critical assessments plays an important role in guaranteeing pipeline integrity when pipes are subjected to complex loads induced by a hostile environm...

The urban infrastructure serves as lifelines for the normal operation and sustainable development of the city. The heating pipeline is one of the most important infrastructures of the urban lifeline system. At present, the design of directly buried heating pipeline is mainly based on the stress failure criterion. Since the large diameter directly b...

Geohazards have become one of the major threats for pipeline safety as catastrophic consequences can be induced by the ground displacement. To prevent pipe failure, multi-source monitoring technics have been adopted by pipeline operators in engineering practice. While the strain gauge monitored strain results are discretely distributed along the pi...

Anomalies as misalignment, microcrack are inevitable for large diameter high strength steel pipelines. To ensure the strain capacity of mismatched welding joint with misalignments of D1422 mm X80 steel pipeline, a comprehensive study via wide plate experiments and finite element model simulations was conducted. The full-scale tensile experiment of...

Oils are mainly transported by pipe in long distance for its high efficiency. While oil pipe leakage will cause serious social and environmental consequences, e.g. fire even life lost, water and soil pollution. Thus it is important to recognize pipe leakage at initial stage in engineering practice. In this research, a negative pressure wave based d...

Acoustic resonance in closed side branches should be enhanced to improve the efficiency of wind energy harvesting equipment or thermo-acoustic engine. However, in gas pipeline transportation systems, this kind of acoustic resonance should be suppressed to avoid fatigue damage to the pipeline. Realizable k-ε delayed detached eddy simulations (DDES)...

Significant progress in the oil and gas industry advances the application of pipeline into an intelligent era, which poses rigorous requirements on pipeline safety, reliability, and maintainability, especially when crossing seismic zones. In general, strike-slip faults are prone to induce large deformation leading to local buckling and global ruptu...

Thaw settlement is one of the common geohazard threats for safe operation of buried pipelines crossing permafrost regions, as pipes need to bear additional bending stress induced by settlement load. In the presented study, a novel coupled data analysis method was proposed for stress state estimation of buried steel pipeline under thawing settlement...

The pipeline inspection gauge (PIG) is one of the most popular pigging equipment. In recent years, blocking and stagnation accidents during PIG’s operation process seriously affect the safe operation of energy pipelines. In order to investigate the sealing performance of the PIG’s rubber cup, a four cup drain PIG’s movement in elbow was considered...

Differential settlement has a significant effect on the safe operation of tanks. In order to investigate the stress response of crude oil storage tank subjected to harmonic settlement. A numerical simulation model of the steel storage tank was developed in this study. Based on a validated finite element model, parametric analysis was conducted base...

The tectonic fault poses a great threat to buried pipe segments. Buckling or rupture of pipes will ensue due to large strain induced by continuously increasing fault movements. In this study, a reliability-based methodology is conceptually proposed for designing new buried pipes or assessing existing pipes installed in fault areas. Uncertainties as...

Permafrost thawing caused by the hot crude pipeline is a major threat to the safe operation of buried pipelines in permafrost zone. In this paper, the process of thawing and consolidation of frozen soil is considered, and a three-dimensional (3D) finite element model of buried pipelines in permafrost zone is established using ABAQUS. The calculatio...

Unbonded flexible pipe is widely used in the oil and gas industry for its good flexibility, especially in deepwater oil and gas transportation. And the fiber reinforced unbonded flexible pipe has excellent corrosion resistance and wear resistance. However, they are subjected to internal pressure, external pressure and tensile loads during the servi...

Buried pipelines in permafrost regions are inevitably subjected to some typical geohazards, such as frost heave, thaw settlement and thaw slumping. The bending or/and longitudinal strains will be induced in pipe under these types ground movement, which is the potential cause of weld joint rupture. Thus, in order to prevent pipe failure, a comprehen...

Abrupt permanent ground displacement is a typical loading condition for pipelines crossing geotechnical hazard areas. An improved analytical method for calculating longitudinal strain of buried pipeline under tension combined with bending load induced by permanent ground displacement (PGD) was proposed, in which, the pipe steel was considered as a...

The tectonic fault, which is one of the most common geohazards in field, poses great threat to buried pipe segments. Pipes will process to buckling or fracture due to large strain induced by continuously increasing ground displacements during earthquakes. Therefore, it is imperative to conduct safety analysis on pipes which are buried in seismic ar...

The active fault is one of the commonest geological disasters in the pipeline construction. Excessive tensile or compressive strain may be induced in pipelines which may lead to the rupture or buckling when the two fault plates generate relative movement on the fault plane so that the pipeline cannot operate normally. In this study, a finite elemen...

A circumferential crack in the fusion line is a major threat to the structural integrity of the pipeline girth weld because it may possibly lead to fracture failure when subjected to large plastic deformations. For the newly constructed X80 pipeline with an outside diameter (OD) of 1422 mm in China, the complicated configuration of welded joints an...

With continued increasing construction of both electrified facilities and buried high‐strength pipelines in China, stray current corrosion defects have become an nonignorable threat for these pipelines. A comprehensive investigation on a new failure pressure prediction model for high‐strength pipes with stray current corrosion defects was conducted...

Rupture of steel pipelines due to combined loading conditions leads to the loss-of-containment that may be accompanied by property damage or fatal accidents. Therefore, the understanding of the fracture characteristics of steel grades used in the pipelines is essential for a safe and reliable design. In this study, a set of small-scale fracture tes...

Reinforced thermoplastic pipe (RTP) is used in the oil and gas industry for its good flexibility, corrosion resistance and wear resistance, especially in offshore oil and gas production process. However, they are subject to internal pressure, external pressure and tension loads that are important aspects affecting the integrity and security of the...

Reinforced thermoplastic pipe (RTP) is used in the oil and gas industry for its good flexibility, corrosion resistance and wear resistance, especially in offshore oil and gas production process. However, they are subject to internal pressure, external pressure and tension loads that are important aspects affecting the integrity and security of the...

A short discussion was put forward by Shadab Far (2018) pointing out some limitations of the published research by Liu et al. (2016) on a semi-empirical model for peak strain prediction of X80 pipelines. This paper is hereby presented in an attempt to tackle the limitations pointed out by Shadab Far. Firstly, an error pointed out in the legend of F...

The rapid development of offshore oil and gas resources in recent years has led to a steadily growing importance of the safety of offshore pipelines. Active faults are some of the main geological hazards to which onshore and offshore pipelines may be subjected. In this study, an improved analytical method for estimating the strains in offshore pipe...

Hollow structures are widely used in industry for their high bearing capacity. In some engineering cases, these structures are always subjected to complicated non-uniform external loads. For example, bored (foundation) Piles steel casing, and steel casing used for oil production are subjected to non-uniform ground stresses. In this study, a general...

In service pipelines exhibit bending loads in a variety of in-field situation. These bending loads can induce large longitudinal strains, which may trigger local buckling on the pipe's compressive side and/or lead to rupture of the pipe's tensile side. In this article, the post-buckling failure modes of pressurized X65 steel pipelines under monoton...

The buckling capacity of uniformly compressed flat plates has been investigated in this study. Material properties were characterized based on parameterization of the stress-strain curves using a simple and novel mathematical expression. Idealized stress-strain relationships were developed using the proposed material model and extensive parametric...

This paper is concerned with the flexural vibration analysis of rotating Timoshenko beams by using the variational iteration method (VIM). Accurate natural frequencies and mode shapes of rotating Timoshenko beams under various rotation speeds and rotary inertia are obtained. The VIM solutions are verified by comparing with some existing results in...

Pipelines in service always experience complicated load-ings induced by operational and environmental conditions. Flood is one of the common natural hazard threats for buried steel pipelines. One exposed river crossing X70 gas pipeline induced by flood erosion was used as a prototype for this study. A mechanical model was established considering th...

Pipeline is the safest and most economical means for transporting oil and natural gas resources over long distances. High strength steel pipelines have become widely used in recent years, for using higher strength line-pipe allows higher operating pressure with increased throughput. These pipelines are inevitable to cross geological hazard areas, l...

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...

Polyethylene (PE) pipelines are the most popular kinds of urban gas pipelines used in industry. With rapid development of urban pavement construction and increasing demand of natural gas in China. Urban gas pipe accidents caused by pavement mechanical construction have taken place more frequently in recent years, which becomes one main reason for a...

As a main defect in pipeline, dents have brought great challenge to the integrity of oil and gas pipelines. Numerical study was presented in this paper to investigate the stress and strain state of dented X60 pipe. Suitable failure criteria is adopted and validated by full scale exper-imental results. And the failure process of dented X60 pipe is e...

As a typical hazard threat for buried pipelines, an active fault can induce large plastic deformation in a pipe, leading to rupture failure. The mechanical behavior of high-strength X80 pipeline subjected to strike-slip fault displacements was investigated in detail in the presented study with parametric analysis performed by the finite element mod...

We have noticed some errors in regression coefficients of proposed semi-empirical formula in [J. Nat. Gas Sci. Eng. 32(2016) 465-475] in calculating the peak compressive strain for buried X80 steel pipeline crossing strike-slip faults.

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...

High strength line-pipe steels are widely used in long distance gas pipelines. Fracture toughness is one major parameter in the performance evaluation of these line-pipe steels. For high strength line-pipe steels, critical crack tip opening displacement (CTOD) is one typical quantity for fracture toughness. In this paper, a series of experimental s...

Due to the harsh environment for submarine pipelines, corrosion damage of the pipeline steels is inevitable. After the corrosion damage, pipelines are prone to failure and may cause serious consequences. The analysis of the effects of different steel properties on the collapse pressure of pipelines with corrosion defects is of importance for the op...

Fatigue crack growth rate is a significant mechanical property of high strength pipe. Some properties of fatigue crack propagation can be obtained by evaluating the mechanical performance of the material. In this study experiment studies were conducted with the fatigue crack growth rate test for two commonly used high strength pipe steels, X70 and...

High strength pipelines is widely used for the long distance transportation of oil and gas resources. Fracture toughness is a significant material property for these high strength pipeline steels. In this study, the critical crack tip opening displacement (CTOD) of X80 pipeline steel was studied both experimentally and numerically. 3 point bending...

With the rapid development of offshore oil and gas resources. The safety of offshore pipelines become more and more important in recent years. Active faults occurred during earthquakes is a main geological hazard faced by both onshore and offshore pipelines. While few researches focused on the stress and strain reaction of offshore pipelines. In th...

Active fault is one of the main geological hazards for long-distance transportation pipeline. Ground movement caused by faults may cause large strain in pipe in the potential of leading to failures and accidents. Using loose granular sand backfill is a common aseismic measure for buried steel pipelines in seismic areas. In this paper, a rigorous fi...

Oil tubes containing corrosion defects are vulnerable under complicated service load. In the oil field, corrosion of oil tubes is mainly electrochemical corrosion. In this study, failure analysis of the oil tube with two typical electrochemical corrosion defects, the grooving defect and the ellipsoidal pit, was conducted by finite element method. T...

There is a potential for major damage to the pipelines crossing faults, therefore the strain-based design method is essential for the design of buried pipelines. Finite element models based on soil springs which are able to accurately predict pipelines’ responses to such faulting are recommended by some international guidelines. In this paper, a co...

Corrosion defect in oil tubes is one main threat for the safety production of oil field. The corrosion defect in the tube will cause stress concentration and even lead to failure. The injection of CO2 widely used during the recent years in oil fields, making the corrosion problems more severe. In this study a finite element model for the residual s...

Active fault is one of the main geological hazards for long-distance transportation pipeline. Ground movement caused by faults may cause large strain in pipe in the potential of leading to failures and accidents. Using loose granular sand backfill is a common aseismic measure for buried steel pipelines in seismic areas. In this paper, a rigorous fi...

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 com...

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 com...

A set of generalized solutions are proposed for estimating ultimate load capacity of pipeline with arbitrary corrosion shapes subjected to combined internal pressure, axial force and bending moment. Isotropic and anisotropic material characteristics in longitudinal and circumferential direction of pipeline are also considered in the proposed equati...

Active faults pose threats to the long-distance oil & gas pipelines cross the seismic zones and the axial and vertical displacement of pipes will occur under the action of faulting, resulting in the pipe's failure by a great inside strain. In this case, the accurate calculation of the strain in the pipe is of great significance to the pipe design a...

Based on Hencky's total strain theory of plasticity, limit bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material, the simplified analytical solution is proposed as well. Good agreement is observed when limit bending capacities obtained from analytical solutions are compared with experime...

Experimental methodologies of pipeline buckling are investigated on an initial stage. Critical axial buckling load of different pipeline structures under separate influential factors are simulated utilizing pipeline buckling experimental instruments manufactured based on theories mentioned above so as to specify effects of different factors on crit...

Based on non-linear finite element analysis, design strain of pipeline made of X80 steel crossing active fault is analyzed in this paper. The sensitivities of the diameter, wall thickness, soil rigidity, fault displacement and crossing angle on the design strain of the pipeline are examined in detail. Furthermore, regression equations are proposed....