Advanced Analysis and Design Tools for Offshore Pipeline in Operation

Author(s):  
Lorenzo Bartolini ◽  
Cristian Crea ◽  
Lorenzo Marchionni ◽  
Maurizio Spinazze` ◽  
Luigino Vitali

In the last thirty years, the attention of the offshore pipeline industry has been strongly focused on submarine pipelines crossing very uneven seabed. New pipelines crossing the uneven seabed of the Mediterranean Sea and of the North Sea and deep water pipelines crossing the uneven continental slope of the Gulf of Mexico are outstanding examples. Pipeline structural integrity may be threaten by large free-spanning sections between rocky peaks and deep depressions that may be coupled with the pipeline propensity to develop lateral/vertical deflection due to severe service conditions (High Pressure/High Temperature). Generally, these scenarios require mitigation measures aiming to control the development of excessive bending moment/deformation by means of Finite Element (FE) Modeling. FE Modeling gives a valuable contribution to the pipeline engineering at identifying a technical and cost effective solution since the early phase of the project. Finite Element (FE) Model approaches, based on standard structural finite element codes available on the market, such as ABAQUS, ADINA, ANSYS etc., are commonly used to analyze the effects of non-linearity, e.g. steel material, soil-pipe interaction and large rotations/displacements. 3-Dimensional FE Models permit to predict the overall pipeline global response under design loads taking into account the expected (during design phase) and/or actual (after measurements gathered during as-built survey campaign) 3-Dimensional pipeline configuration including 3-Dimensional (along and transversal to the pipeline route) bottom roughness, route bends, intervention works for bottom roughness and free-span correction and mitigation measures against HP/HT condition in operation. In this paper: • The design approach for HP/HT pipelines is described; • The main features of the ABAQUS FE Model, developed to predict the behavior of offshore pipelines in operation, are presented; • Two relevant examples of offshore pipelines subject to pressure and temperature conditions are presented with and without mitigation measures.

Author(s):  
Lorenzo Maria Bartolini ◽  
Lorenzo Marchionni ◽  
Maurizio Spinazzè ◽  
Giulio Claudio Vignati ◽  
Luigino Vitali

In the last thirty years the attention of the offshore pipeline industry has been strongly focused on submarine pipelines crossing harsh environments and subject to severe operating conditions of temperature and pressure. Pipeline structural integrity may be threaten by large free-spanning sections between rocky peaks and deep depressions that may be coupled with the pipeline propensity to develop lateral/vertical deflection due to severe service conditions (high pressure/high temperature). For short flowlines, pipeline walking is an additional issue to be verified and faced during design and the application of an integrated approach between flow assurance, installation, geotechnics and pipeline design is a must. All these features characterize new load scenarios for which intervention works are mandatory to control the development of excessive loads and deformations within acceptance criteria. 3-Dimensional Finite Element Models permit to anticipate the pipeline global response under design loads taking into account the expected (during design phase) and/or actual (after measurements of the as-built) 3-Dimensional pipeline configuration. In case that mitigation measures are to be installed along the pipeline route, their effectiveness can be verified and optimized. Potential failure events in the most promising mitigation measure strategy can be investigated and anticipated at design stage. This paper describes the most relevant capability of the pre- and post-processing tools developed in MATLAB environment and based on ABAQUS Finite Element.


Author(s):  
Lorenzo Marchionni ◽  
Lombardi Alessandro ◽  
Luigino Vitali

The future offshore pipeline development projects envisage the installation of medium to large diameter pipelines (16″ to 32″ ND) transporting gas from the deep waters to the shallow water areas. The development of these deep water projects is limited by the feasibility/economics of the construction phase using the J-lay or the S-lay technology. In particular, the S-lay feasibility depends on the applicable tension at the tensioner which is a function of water depth, stinger geometry (length and curvature), and installation criteria. In this paper: – The challenges of future deep water offshore pipelines are briefly presented; – The installation criteria at the overbend, stinger tip and sagbend are discussed; – The ABAQUS FE Model, developed to simulate pipeline installation, is presented together with the pre- and post-processing program put in place; – The results of the developed ABAQUS FE Model are given considering two typical examples of deep water pipelines installed in the S-lay mode.


2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Derek A. Jones ◽  
James P. Gaewsky ◽  
Mona Saffarzadeh ◽  
Jacob B. Putnam ◽  
Ashley A. Weaver ◽  
...  

The use of anthropomorphic test devices (ATDs) for calculating injury risk of occupants in spaceflight scenarios is crucial for ensuring the safety of crewmembers. Finite element (FE) modeling of ATDs reduces cost and time in the design process. The objective of this study was to validate a Hybrid III ATD FE model using a multidirection test matrix for future spaceflight configurations. Twenty-five Hybrid III physical tests were simulated using a 50th percentile male Hybrid III FE model. The sled acceleration pulses were approximately half-sine shaped, and can be described as a combination of peak acceleration and time to reach peak (rise time). The range of peak accelerations was 10–20 G, and the rise times were 30–110 ms. Test directions were frontal (−GX), rear (GX), vertical (GZ), and lateral (GY). Simulation responses were compared to physical tests using the correlation and analysis (CORA) method. Correlations were very good to excellent and the order of best average response by direction was −GX (0.916±0.054), GZ (0.841±0.117), GX (0.792±0.145), and finally GY (0.775±0.078). Qualitative and quantitative results demonstrated the model replicated the physical ATD well and can be used for future spaceflight configuration modeling and simulation.


2017 ◽  
Vol 754 ◽  
pp. 268-271 ◽  
Author(s):  
Raffaele Sepe ◽  
M. Laiso ◽  
A. de Luca ◽  
Francesco Caputo

The study proposed within this paper deals with an application of finite element techniques to the thermo-structural analysis of a dissimilar butt-welded joint. Residual stresses induced by the fusion arc-welding of steel joints in power generation plants are a concern to the industry. Nowadays, the application of finite element method appears to be a very efficient method for the prediction and the investigation of the weld-induced residual stresses, nevertheless the detailed modelling of all phenomena involved in such process is still challenging. The structural integrity assessment of welded structures strongly requires a deep investigation of weld-induced residual stresses in order to be compliant with safety requirement of power plant. The longitudinal and transversal residual stresses in dissimilar material butt joints of 8 mm thick for V-groove shape were studied. The developed thermo-mechanical FE model as well as the simulation procedures are detailed and results are discussed. As a result of such work, it has been found out that residual stresses in the two dissimilar plates are characterized by very different magnitudes and distribution.


2020 ◽  
Vol 142 (2) ◽  
Author(s):  
J. S. Kim ◽  
Y. F. Xu ◽  
W. D. Zhu

Abstract Riveted connections are widely used to join basic components, such as beams and panels, for engineering structures. However, accurately modeling joined structures with riveted connections can be a challenging task. In this work, an accurate linear finite element (FE) modeling method is proposed for joined structures with riveted connections to estimate modal parameters in a predictive manner. The proposed FE modeling method consists of two steps. The first step is to develop nonlinear FE models that simulate riveting processes of solid rivets. The second step is to develop a linear FE model of a joined structure with the riveted connections simulated in the first step. The riveted connections are modeled using solid cylinders with dimensions and material properties obtained from the nonlinear FE models in the first step. An experimental investigation was conducted to study accuracy of the proposed linear FE modeling method. A joined structure with six riveted connections was prepared and tested. A linearity investigation was conducted to validate that the test structure could be considered to be linear. A linear FE model of the test structure was constructed using the proposed method. Natural frequencies and corresponding mode shapes of the test structure were measured and compared with those from the linear FE model. The maximum difference of the natural frequencies was 1.63% for the first 23 out-of-plane elastic modes, and modal assurance criterion values for the corresponding mode shapes were all over 95%, which indicates high accuracy of the proposed linear FE modeling method.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1147-1150
Author(s):  
Kang Liu

A finite element (FE) model for externally bonded FRP (EB-FRP) strengthened RC beams is developed to simulate the responses of the structural system, to gain a better insight into the mechanism of the system. Comparisons between the predictions of the model and test results are presented to demonstrate its capability and accuracy.


Author(s):  
A. M. Kiapour ◽  
A. Kiapour ◽  
C. K. Demetropoulos ◽  
V. K. Goel

The anterior cruciate ligament (ACL) is one of the most frequently injured ligaments of the knee, with a prevalence estimated to be 1 in 3000 in the U.S. population. Current approaches to biomechanical finite element (FE) modeling of the knee are at a crossroads. While the ideal scenario for clinically applicable FE modeling would be a subject-specific approach with detailed, image-based anatomic reconstruction of the joint, the computational intensity of such an approach would almost certainly preclude its clinical applicability. The assumption that an accurate assessment of an individual’s ACL injury risk profile can be attained through generalized FE models also has yet to be tested. The current study aims to test a novel framework in which the developed, validated generic FE model will be customized to each specimen based on quantified ACL structural properties (mechanical and anatomical). We hypothesized that personalized FE models using the proposed framework will result in more accurate predictions of ACL strain (as an established measure of injury risk) compared to the generic FE model. Thus, these models may serve as individual-based injury risk assessment tools.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jiandong Huang ◽  
Tianhong Duan ◽  
Yuantian Sun ◽  
Lin Wang ◽  
Yawei Lei

DAMs have recently been developed to be used as the damping layer in the so-called antivibration pavement to mitigate the effects of traffic-induced vibration while rare finite element (FE) modeling has been conducted to simulate the indirect tension to cylindrical (IT-CY) specimen test for DAMs. In the present study, the methods for the viscoelastic characterization of DAMs and the techniques to characterize the viscoelastic behavior of DAMs in FE modeling were proposed. The FE model to simulate the IT-CY test was constructed, and it was verified through the corresponding laboratory test. Good agreements were noted between the simulation results and testing results demonstrating that the FE model can provide the accurate prediction of the mechanical behavior of DAMs.


2012 ◽  
Vol 134 (6) ◽  
Author(s):  
N. Nourpanah ◽  
F. Taheri

The strain concentration at the field joint (FJ) of the commonly used concrete coated offshore pipelines is considered and discussed in this paper. The details of a 3D finite element (FE) modeling framework, developed using the commercial software ABAQUS, are presented. The numerical results are verified against the experimental results available in the literature. The FE model considered in this study captures several nonlinear phenomena associated with the problem, including the plastic deformation of the steel and anticorrosion layer (ACL) material, the cracking and crushing of the concrete, and also the large deformation effects. The developed FE framework is subsequently used to perform a parametric study to assess the effect of each influencing parameter on the strain concentration factor (SCF) developed within the FJ region. The influence of the geometric features of the coated pipe and the relevant mechanical properties of the materials as well as various combined loading scenarios are investigated. Results indicate that pipeline diameter, thickness, and coating thickness affect the SCF more than the strength of either concrete coating or ACL. Also, the postyield properties of the steel, especially the strain hardening capacity, may significantly influence the SCF. The combination of the internal pressure loading (causing a biaxial stress state) or tensile loading with the primary bending load is found to also increase the SCF significantly after steel yielding is initiated. Moreover, these combined loading scenarios cause different and more severe plastic deformation patterns in the FJ.


2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Lim Kar Sing ◽  
Nordin Yahaya ◽  
Alireza Valipour ◽  
Libriati Zardasti ◽  
Siti Nur Afifah Azraai ◽  
...  

Oil and gas pipelines are subjected to various types of deterioration and damage over long service years. These damaged pipes often experience loss of strength and structural integrity. Repair mechanisms have been developed in restoring the loading capacity of damaged pipelines, and composite repair systems have become popular over the past few years. The mechanical properties of the putty/grout are critical to their potential application as infill materials in structural repair. In this paper, the compression, tensile, and flexural behavior of four epoxy grouts was investigated through laboratory tests. The stiffness of the grouts for compression, tensile, and flexural was found to be 6 GPa to 18 GPa, 4 GPa to 15 GPa, and 4 GPa to 12 GPa, respectively. The ultimate strength for all grouts was found from 62 MPa to 87 MPa, 18 MPa to 38 MPa, and 34 MPa to 62 MPa under compression, tensile, and flexural tests, respectively. The behavior of all the tested grouts is discussed. A finite element (FE) model simulating a composite-repaired pipe was developed and compared with past studies. The FE results show a good correlation with experimental test with margin of error less than 10%. By replacing the infill properties in FE model to mimic the used of different infill material for the repair, it was found that about 4–8% increment in burst pressure can be achieved. This signifies that the role of infill material is not only limited to transferring the load, but it also has the potential to increase overall performance of composite-repaired pipe.


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