Development of a Pipeline Wrinkle Material Ultimate Limit State: Full Scale Modeling

Author(s):  
Vlado Semiga ◽  
Sanjay Tiku ◽  
Aaron Dinovitzer ◽  
Joe Zhou ◽  
Millan Sen

While the formation of a wrinkle in an onshore pipeline is an undesirable event, in many instances this event does not have immediate pipeline integrity implications. The magnitude or severity of a wrinkle formed due to displacement controlled loading processes (e.g. slope movement, fault displacement, frost heave and thaw settlement) may increase with time, eventually causing serviceability concerns (e.g. fluid flow or inspection restrictions). Pipe wall cracking and eventually a loss of containment involves contributions from the wrinkle formation process, as well as wrinkle deformations caused by in-service line pressure, temperature and seasonal soil displacements. The objective of this paper is to provide an overview of the ongoing research efforts, sponsored by TransCanada PipeLines Ltd, towards the development of a mechanics based wrinkle ultimate limit state that may be used in future to evaluate the long term integrity of wrinkled pipeline segments. The research efforts include testing and non-linear finite element modeling of a full scale wrinkled pipeline segment. This paper outlines the development of the full scale finite element model, including the detailed material model development, used to estimate the fatigue life of the experimental full scale fatigue test specimen. A comparison is then carried out between the experimental results and the results from the finite element analysis.

2015 ◽  
Vol 32 (5) ◽  
pp. 1477-1524 ◽  
Author(s):  
George Markou ◽  
Manolis Papadrakakis

Purpose – The purpose of this paper is to present a simplified hybrid modeling (HYMOD) approach which overcomes limitations regarding computational cost and permits the simulation and prediction of the nonlinear inelastic behavior of full-scale RC structures. Design/methodology/approach – The proposed HYMOD formulation was integrated in a research software ReConAn FEA and was numerically studied through the use of different numerical implementations. Then the method was used to model a full-scale two-storey RC building, in an attempt to demonstrate its numerical robustness and efficiency. Findings – The numerical results performed demonstrate the advantages of the proposed hybrid numerical simulation for the prediction of the nonlinear ultimate limit state response of RC structures. Originality/value – A new numerical modeling method based on finite element method is proposed for simulating accurately and with computational efficiency, the mechanical behavior of RC structures. Currently 3D detailed methods are used to model single structural members or small parts of RC structures. The proposed method overcomes the above constraints.


2011 ◽  
Vol 225-226 ◽  
pp. 823-826
Author(s):  
Yu Feng Zhang ◽  
Guo Fu Sun

As a part of virtual simulation of construction processes, this paper deals with the quantitative risk analysis for the construction phases of the CFST arch bridge. The main objectives of the study are to evaluate the risks by considering an ultimate limit state for the fracture of cable wires and to evaluate the risks for a limit state for the erection control during construction stages. Many researches have been evaluated the safety of constructed bridges, the uncertainties of construction phases have been ignored. This paper adopts the 3D finite element program ANSYS to establish the space model of CFST Arch Bridge, and to calculate the linear, the geometrical nonlinear and the double nonlinear buckling safety factors under the six different lode cases. Then the bridge’s risks are evaluated according to the results calculated which provide a reference for design of similar project.


Author(s):  
B. Scott Kessler ◽  
A. Sherif El-Gizawy

The accuracy of a finite element model for design and analysis of a metal forging operation is limited by the incorporated material model’s ability to predict deformation behavior over a wide range of operating conditions. Current rheological models prove deficient in several respects due to the difficulty in establishing complicated relations between many parameters. More recently, artificial neural networks (ANN) have been suggested as an effective means to overcome these difficulties. In the present work, a previously developed ANN with the ability to determine flow stresses based on strain, strain rate, and temperature is incorporated with finite element code. Utilizing this linked approach, a preliminary model for forging an aluminum wheel is developed. This novel method, along with a conventional approach, is then measured against the forging process as it is currently performed in actual production.


2011 ◽  
Vol 243-249 ◽  
pp. 527-530 ◽  
Author(s):  
Wen Da Wang ◽  
Zhi Feng Guo ◽  
Yan Li Shi

The steel tube confined concrete (STCC) column exhibits excellent mechanical performance. A 3-D finite element model (FEM) using ABAQUS was established to simulate the performance of the composite joints with STCC column and RC beam. Accurate material model, rational element type, and solution method were discussed. Some STCC columns and composite joints with concrete-filled steel tubular (CFST) column and STCC column were modeled based on the model, respectively. The results from FEM are good agreement with the test results. The mechanism of the composite joint was investigated based on the FEM.


Author(s):  
T. Sriskandarajah ◽  
Venu Rao

Accurate determination of residual ovality is an important parameter for a successful deployment of single pipeline and pipe-in-pipe in deep waters wherein the integrity of empty pipes during installation depends upon the collapse resistance under external hydrostatic pressure. The reel-lay process of installation during which pipeline undergoes multiple strain cycles due to spooling, reeling and straightening has a significant bearing on pipe ovalisation and hence accurate determination residual ovality at the end of straightening process is one of the key inputs. It is industry practice to use numerical finite element analysis techniques to predict residual ovality of pipelines as full scale testing is expensive and time consuming. In view of the importance of residual ovality on the pipeline integrity particularly for deepwater applications, an integrated approach of testing and finite element simulation have been used to identify the correct numerical model that predicts residual ovality accurately. This paper discusses the full scale tests performed which include material testing and bend tests performed to simulate spooling and straightening process and the pipeline deformations recorded using laser measurements at different cycles of bending process. The paper presents a brief summary of numerical finite element analyses performed to validate the test results and the effect of element types and material models used in the finite element analyses on the predictability of residual ovality. The material evolution models and their effect on the predictability of remaining ovality are discussed in the paper. Comparisons are made on the predictive residual ovality for reel lay process on single pipe and pipe-in-pipe. The effect of residual ovality on the pipeline integrity for the lateral buckling limit state under combined bending and external pressure are discussed in the paper.


Author(s):  
Patricia Llana ◽  
Richard Stringfellow ◽  
Ronald Mayville

The Office of Research and Development of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. In recognition of the importance of override prevention in train-to-train collisions in which one of the vehicles is a locomotive, and in light of the success of crash energy management technologies in cab car-led passenger trains, the Volpe Center seeks to evaluate the effectiveness of components that could be integrated into the end structure of a locomotive that are specifically designed to mitigate the effects of a collision and, in particular, to prevent override of one of the lead vehicles onto the other. A research program has been conducted to develop, fabricate and test two crashworthy components for the forward end of a locomotive: (1) a deformable anti-climber, and (2) a push-back coupler. Detailed designs for these components were developed, and the performance of each design was evaluated through large deformation dynamic finite element analysis (FEA). Designs for two test articles that could be used to verify the performance of the component designs in full-scale tests were also developed. The two test articles were fabricated and dynamically tested by means of rail car impact in order to verify certain performance characteristics of the two components relative to specific requirements. The tests were successful in demonstrating the effectiveness of the two design concepts. Test results were consistent with finite element model predictions in terms of energy absorption capability, force-displacement behavior and modes of deformation.


Author(s):  
Anna Ermakova

The paper considers the example of gradual transformation of the stiffness matrix and the main set of equations at Additional Finite Element Method (AFEM). It is corresponded to the increase of load and the ideal failure model of structure. AFEM uses the additional design diagrams and additional finite elements (AFE) for this operation. This process is illustrated by the transformation of design diagram of bended concrete console from the beginning of its loading to the collapse. The structure reveals four physical nonlinear properties before the ultimate limit state. Every nonlinear property appears under the action of corresponded load. The stiffness matrix and the set of equations are changed under influence of the value of load and the presence of observed nonlinear properties at this moment.


Author(s):  
Prabin Pathak ◽  
Y. X. Zhang

A simple, accurate and efficient finite element model is developed in ANSYS for numerical modelling of the nonlinear structural behavior of FRP strengthened RC beams under static loading in this paper. Geometric nonlinearity and material non-linear properties of concrete and steel rebar are accounted for this model. Concrete and steel reinforcement are modelled using Solid 65 element and Link 180 element, and FRP and adhesive are modelled using Shell 181element and Solid 45 element. Concrete is modelled using Nitereka and Neal’s model for compression, and isotropic and linear elastic model before cracking with strength gradually reducing to zero after cracking for tension. For steel reinforcement, the elastic perfectly plastic material model is used. FRPs are assumed to be linearly elastic until rupture and epoxy is assumed to be linearly elastic. The new FE model is validated by comparing the computed results with those obtained from experimental studies.


Author(s):  
K W Dalgarno ◽  
A J Day ◽  
T H C Childs

This paper describes a finite element analysis of a synchronous belt tooth under operational loads and conditions with the objective of obtaining a greater understanding of belt failure by tooth root cracking through an examination of the strains within the facing fabric in the belt. The analysis used the ABAQUS finite element program, and was based on a two-dimensional finite element model incorporating a hyperelastic material model for the elastomer compound. Contact between the belt tooth face and the pulley groove was modelled using surface interface elements which allowed only compression and shear forces at the contact surfaces. It is concluded that the critical strains in the facing fabric of the belt, and therefore the belt life, are largely determined by the tangential loading condition on the belt teeth.


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