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An experimental and numerical investigation on the mechanical response of a lined pipe (compound pipe) under a dynamic impact is presented. The influence of the impact energy has been studied in terms of the depth of the dent formed, and of the strains and residual stresses. To this end, a three-dimensional explicit dynamic non-linear finite elemen...
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... a quarter model is simulated, because of symmetry with respect to the axial and transverse planes, planes X-Y and Y-Z, respectively. Fig. 5 shows the FE mesh for the main parts of lined pipe impact process, for case B. ...
Context 2
... order to examine the effect of using the liner, it could be seen that the internal energy is increased by 3% in case H1B corresponding to its counterpart in case H1A, when forming the maximum dent depth, after 7.5 ms, as shown in Fig. 15(d). This increase is attributed to the increase in plastic energy which is applied to deform two pipes. Furthermore, the penalty contact between the AISI304 pipe and C-Mn pipe on the entire length has a significant effect on the work energy and the viscous dissipation energy in case H1B. The frictional energy increases slightly with ...
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An experimental and numerical investigation on the thermal and mechanical response of a lined pipe (compound pipe) under welding is presented. The welding process consists of a single-pass overlay welding (inner lap-weld) and a two-pass girth welding (outer butt-weld). The influence of the filler material of the girth welding has been examined ther...
Citations
... For instance, in the study regarding single-layer pipes, the effect of various factors on the collapse, such as material properties, dimensions, and initial geometric defects, was extensively studied [8][9][10][11]. As to lined pipes, some researchers have conducted work to study the relationship between dent depth and impact energy during dynamic indentation [12,13]. Moreover, Yuan et al. [14] also combined finite element analysis (FEA) and machine learning techniques to develop a predictive framework for lined pipe collapse capacity. ...
Mechanically lined pipes (MLP), known for their cost-effectiveness and reliability in transporting corrosive oil and gas, have increasing applications in offshore projects. The presence of the non-corrosive liner, although relatively thin, will increase the collapse capacity of MLP to some extent. In addition, the mechanical property changes induced by hydraulic plastic expansion during manufacturing are also expected to influence the buckling behavior of lined pipes. However, this problem is still less understood, and related studies about MLP collapse are mostly limited to numerical simulations instead of experiments.
In this work, we conducted a series of small-scale experiments on the mechanically lined tubes. The lined pipes, made of carbon steel Grade GB45 (AISI 1045) and T2 copper, are manufactured using a custom hydraulic expansion facility. The products have finished diameters of 50 mm and an overall D/t of 16.5, with 1.0 mm thickness for the liner. Afterward, intact and minorly dented specimens were collapsed under external pressure in a sealed hyperbaric chamber. The collapse pressure and final configuration of the tubes were recorded. In addition, the experimental results were reproduced by finite element models, which takes account for both the manufacture and collapse stages, and good agreement was reached.
... In the paper [13] proves that the impact energy directly influences the depth formed, including the effect of strains and residual stresses. The paper of [14] investigates that buckling is identified as local plastic deformation that impacts the pipelines' failure to deliver liquid and gas. ...
This work reports the development of inline inspection (ILI) methodology to enhance the pigging activity for the dented pipeline, facilitate the pigging process to prevent Pipeline Inspection Gauge (PIG) from getting stuck and improve the safety passage for buckled pipelines. The recent report unveils the condition of the UNPIGGABLE pipelines, which reduce the inner diameter of pipelines to 257.51 mm, equivalent to 27.58 % of the initial diameter and restricts the pigging activity. In this report, the pull-through test coupled with the collapsibility test was conducted. The success of the test above allows the ILI equipment based on the magnetic flux leakage (MFL) technique to record the internal and external wall loss inwardly and geometric defect on diameter of the pipelines. The prepared artificial dented pipeline was made before it underwent several tests. Based on the pull-through test, the maximum force of 27000 N is more significant than the pipeline operating pressure to enable the MFL tool to pass through the pipelines despite exhibiting the geometry anomaly. Compressing the opposite magnetic yoke of the collapsibility test is critical, showing that the ILI MFL tool reaches its maximum compression of 242 mm. The value is lower than the minimum internal diameter of 257 mm. The ILI results show that the highest metal loss was achieved at 73 % at 15504 m at the bottom of the inspected pipelines. At the same time, the dented area reduces to more than 6 % of the pipelines’ nominal outer diameter and imposes the pipe’s integrity status to red. The distinctive result of the research can be used to model the future unprecedented pigging process when buckles appear in pipelines
... Feng et al. [11] comprehensively considered four basic parameters, namely, the rock mass, fall height, offset distance, and burial depth, to study the additional stresses generated by falling rocks' impact on pipelines, and proposed a rapid method for assessing the additional stresses on pipelines. Obeid et al. [12] carried out a study on the mechanical response of composite pipes under dynamic impact by means of field tests and numerical simulations. All of the similar modeling experiments mentioned above have some assumptions and ignore some factors. ...
Unexpected ground impacts can seriously affect the stability and operational safety of buried pipelines. In this paper, a full-scale modeling test of the dynamic response of a buried concrete pipeline under falling rock impact based on dynamic sensor testing was conducted. A commercially available reinforced concrete pipeline, buried in a clayey soil site, was used, and a 50 kg concrete ball was used to investigate the impact above the pipeline. Considering the purpose of the test, the falling process of the concrete ball and the surface vibration velocity induced by the touchdown of the concrete ball were monitored using a high-speed camera and a vibration signal tester, respectively. The dynamic response signals of the pipe under surface impact were tested using strain gauges and earth pressure gauges combined with dynamic sensors such as dynamic signal tester, and the dynamic response law was analyzed. The experimental results will provide a basis for the design of the impact resistance of reinforced concrete pipes.
... In order to evaluate the mechanical properties of pipelines under low velocity impact loads, many researchers adopt the low velocity impact test method [8]. Obeid et al. [9] studied the mechanical response of a lined pipe (compound pipe) under dynamic impact with experimental and numerical investigation. A three-dimensional explicit dynamic nonlinear finite element model was proposed to evaluate the residual stress, energy dissipation and velocity of the impact process as functions of different pipes and free-fall heights. ...
... where E sa is the energy dissipation coefficient of the pipeline, E a is the energy absorbed by the pipeline, W is the mass per unit length of the pipeline, δ a is the maximum displacement of the pipeline. The energy consumed E a is obtained by integrating the force-displacement curve, as shown in Formula (9). ...
The low velocity impact load on pipes during transportation, construction and operation will cause pipeline damage and lay hidden dangers for the safety of pipeline engineering. To study the low velocity impact performance of pipes made of acrylate polymer blended with polyvinyl chloride resin for water supply (ABR), 20 sets of specimens with different heights and different masses of drop hammer were carried out to study the mechanical properties of ABR pipes. Based on the impact time curve, the energy dissipation capacity and impact peak value of ABR pipe specimens were analyzed, and the empirical calculation formula of impact force peak based on the test data is obtained by the dimensional analysis method, with a relative error ranging from −7.8% to 4.1%. Moreover, the finite element numerical simulation of ABR pipe specimens subjected to impact load is carried out, and the strain development law and failure mode of the pipe under low-speed impact load are analyzed. Therefore, the calculation formula of peak impact force and failure mode proposed in this paper can provide safety assessment methods for pipeline engineering designers and constructors.
... Various installation facilities such as drilling vessels with different configurations, tugboats, and crane barges have been used [25]. In order to avoid the subsequent risks involved in lifting operations, a wide range of modern methods, including the vertical methods [26], the Sheave Installation Method [1,27], the PIM-Pendular Installation Method [28], the Pencil Buoy Method -PBM [7,29], and the Floating Installation Device -FID [30,31] have been the epicenter of the interest to the majority of empiricists. However, considering the optimal grounds, the Y-method comprised two conventional tugboats employed to lift the payload. ...
The subsea equipment installation is a complex operation that demands a precise and reliable approach to avoid the accidental losses of lives and equipment damage. The multibody installation system is overwhelmed with the dynamic behavior and responses of the system, which signifies the importance of analysis of the Multibody Dynamic System (MBDS). The modeling of MBDS is challenging and complicated due to the interconnectivity and nonlinearity assigned to them. In this paper, the planar dynamics of a floating multibody system are attained by employing two tugboats and a payload with a contextual offshore installation scenario to be applied in a water depth of over 1500 m. The lifting operation is nine degrees of freedom (9-DOF) multibody model done with the help of two strands and three bodies having 3-DOF each. The coupled equations of motion are established by deploying the Velocity Transformation Technique. The hydrodynamic and two-strand forces are simplified as linear, while the hydrostatic and mooring forces are treated as nonlinear external loads. The numerical solution to the equations for the MBDS is obtained from the Runge Kutta Method of Fourth-Order. Furthermore, the Finite Element Modeling approach discusses the installation operation using Y-method. The results of the proposed numerical model are validated by comparing it with the numerical simulation from OrcaFlex, and the results from both models are found to be in good agreement. The findings of this study will help improve the safe and stable installation of deep-water multibody structures.
... The number of elements in the transverse direction was 786. Note that at least four elements should be meshed across the wall thickness for thinwalled structures [39]. Figure 2 displays the meshing convergence curve, t À1 means a fraction of the wall thickness. ...
Offshore pressurized pipelines are prone to rupture and perforation in several high-velocity impact conditions. Perforation failure combined with local shear plugging occurs when pressurized pipelines are subjected to flat-nosed impactors, such as torpedoes and explosive projectiles. In this paper, the perforation and plugging phenomena were systemically studied to reveal the failure features and impact limits. Qualitative descriptions of the plugging phenomenon were performed to understand the mode characteristics. The typical impact process for crack propagation and plug formation was analyzed. Effects of structural parameters on rupture and perforation limits were investigated to reveal the failure mechanisms. Simplified mechanical models considering strain rate and internal pressure were proposed to obtain the perforation limit and residual velocity. Critical shear strain and ultimate penetration depth were derived for the mechanical models. These results revealed the plugging phenomena and impact limits of pressurized pipelines impacted by flat-nosed impactors, which can provide the theoretical basis of critical impact conditions for protection design and experience reference of ultimate failure extent for damage assessment.
... Several parametric studies have been conducted on impact responses of empty or pressurised metal pipelines. Studies have investigated the effects of impact velocity (Gemi et al., 2016) (Zeinoddini et al., 2013), pipe wall thickness (Cerik et al., 2016), internal pressure (Obeid et al., 2018) (Gresnigt et al., 2007) (Dou andLiu, 2015), and impactor mass (Tawekal and de Velas, 2019) (Kang et al., 2019) have been investigated. However, most experiments and simulations have been based on center impact, and the parameters are not dimensionless to be suitable in practical applications. ...
... Fig. 2 displays the meshing conditions of the numerical model. Note that at least four elements should be assigned across the wall thickness so that fewer integration elements are required to simulate the thin-walled structure (Obeid et al., 2018). By analysing the mesh convergence and sensitivity, four elements across the thickness were found to be optimal with effective results and excellent computation times. ...
Impact resistance of in-service pressurised X80 pipelines is one of the top safety priorities in the petrochemical industry. Based on impact limits, including the rupture and perforation limits, the failure threshold can be identified and the impact resistance of target structures can be assessed. In this study, backpropagation neural networks (BPNNs) and generalised additive models (GAMs) were developed to predict the rupture and perforation limits of pressurised X80 pipelines. First, an explicit dynamic model was established to provide comprehensive training datasets considering the effects of various dominant parameters. Interdependencies between the impact limits and various dominant parameters were analysed using the Pearson correlation coefficient. Then, BPNN models optimised by the backpropagation algorithm and neuron numbers were trained to predict the impact limits. Based on the optimal smooth functions and smoothing coefficients, the GAMs then provided two integrated regression functions for impact limits. Finally, the predictive stabilities of the BPNN and GAM on impact limits were discussed using a random dataset. The BPNNs and GAMs were in a strong agreement with the expectations, and the predictive accuracy of the BPNNs was approximately three times that of GAMs. The findings of this study can be used as guidelines for protection design and risk assessment of pressurised X80 pipelines.
... In contrast, the structural performance of dented lined pipe is still less understood. Thus far, related publications have mainly focused on the connection between the dent depth and the impact energy during a dynamic indentation (see Obeid et al., 2018;Odina et al., 2018). The present study examines the effect of local dents on the response and stability of lined pipe under bending. ...
As a cost-effective solution for transporting corrosive hydrocarbons, mechanically lined pipe has been used in many offshore and onshore projects. The bonding between the carbon steel carrier and the non-corrosive liner is commonly achieved by mechanical expansion. As typical pipeline damage, the local dent brings deformation to the bimetallic composite, which is expected to undermine the structural integrity. This work investigates the influence of a local dent on the plastic responses and stability of a lined pipe system during bending. Part I presents the results of the experiments and numerical analysis involving a set of small-scale lined tubes. The lined tubes, made of carbon steel Grade GB45 (AISI 1045) and copper Grade T2, are manufactured using a custom hydraulic expansion facility. The products have finished diameters of 50 mm and an overall D/t of 16.5, with 1.0 mm thickness for the liner. A minor transverse dent is introduced to the specimen using a cylindrical indenter. The dented tube is subsequently bent to collapse in a four-point bending facility. It is found that the local dent tends to induce early collapse of both the outer tube and the liner, resulting in a noteworthy reduction of the bending capacity of the composite. Initially, the local dent grows stably instead of collapsing right away. With increasing bending, the liner develops a major buckle and several satellite dimples around it. Subsequently, the manufacture, indentation, and the succeeding bending to collapse are simulated using a custom numerical framework, and the experimental results are reproduced reasonably well. Part II will use the validated numerical model to conduct an extensive parametric study of the important variables of the problem for full-scale lined pipes.
... In oil and gas pipelines with corrosive fluids, the application of pure C-Mn steel pipes (Backing Steel -BS) is avoided. The alternative is to apply a corrosion-resistant alloy (CRA) at the inner diameter, such as Ni alloy 625, SS304, or S316 [6,7]. Conventionally, a thin layer is placed inside the carbon steel pipe using two concepts: MCP -Metallurgically Cladded Pipe or MLP - Fig. 1. ...
The collapse of submarine pipelines can have immense economic and environmental impacts, and understanding the mechanical behavior of such structures under extreme external pressure is vital for the design, fabrication, installation, and operation. The pipe's outer surface is susceptible to damage/impacts due to uncontrolled circumstances, possibly leading to structural changes. This work applies numerical tools to evaluate the collapse and buckle propagation in steel pipes, considering the effects of an initial known deformation caused by different puncher's shapes. Therefore, the structure assumes a new geometry leading to modification in the capacity to withstand external pressure. The analysis applies and compares two numerical methods: the arc-length (Riks) and dynamic-explicit approaches. This comparison allows establishing a direct association between the observed features of the two methodologies. In a general manner, the observation indicates that an increasing indentation causes a reduction in the collapse pressure but also significant changes in the propagation pressure. The similar results between the two methods applied in steel pipes permitted extending this concept to estimate the propagation pressure in Mechanically Lined Pipes (MLPs), where the Riks method is unstable, and the dynamic approach is suitable. In this scenario, the possibility of the internal liner buckling before the external backing steel and the appearance of new failure modes is part of a new complex scenario where the number of variables grows significantly, and the collapse circumstances must be reassessed. The boundary conditions, interface state, and other structural parameters increase the difficulty in this type of analysis, showing that in MLPs the number of variables associated with propagation pressure is much higher than in steel pipes.
... INTRODUCTION journal.ump.edu.my/ijame ◄ Dented and cracked pipes in the presence or absence of internal pressure have been studied in recent years in terms of the risks they pose, using various approaches: theoretical, experimental, or numerical [4][5][6][9][10][11][12][13][14][15]. In the literature, there is still a lack of a model that can be adapted to different types of defects. ...
Pipelines are commonly used to transport energy over long distances. If this structure is subjected to an internal pressure of variable amplitude loading, such as water hammer waves, the structural damage caused by the presence of a defect can be exacerbated. Previous research by the authors resulted in the development of finite element models to evaluate crack and dent defects separately. Each model was used to compare and classify defects in their respective categories based on their nocivity in a metal pipe subjected to internal pressure. The primary objective of this paper is to compare the severity of various defect categories on the same scale. A numerical damage assessment model that considers the interaction effect, as well as the loading history, is used to achieve this goal. It takes the output of the two finite element models, as well as the pressure spectrum caused by the water hammer, as inputs. This model is used to analyze the effect of key parameters that influence the severity of the defects, as well as to compare and classify the various types of dent defects with the various types of crack defects found in pipes subjected to variable amplitude loading.
