Towards a Validated Pipeline Dent Integrity Assessment Model

2008 ◽  
Author(s):  
Brock Bolton ◽  
Vlado Semiga ◽  
Aaron Dinovitzer ◽  
Sanjay Tiku ◽  
Chris Alexander
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Complex Function ◽  
Time History ◽  
Element Model ◽  
Assessment Model ◽  
Third Party ◽  
Assessment Procedure ◽  
Integrity Assessment ◽  
Operational Life

Detectable dents in buried pipelines can occur due to a number of potential causes; the pipe resting on rock, third party machinery strike, rock strikes during backfilling. The integrity of a dented pipeline segment is a complex function of a variety of parameters, including pipe geometry, indenter shape, dent depth, indenter support and pressure history at and following indentation. In order to estimate the safe remaining operational life of a dented pipeline, all of these factors must be accounted for in the analysis. The following paper summarizes ongoing efforts to develop a validated pipeline dent integrity assessment model. The model under development makes use of experimental tests to validate a finite element model of the denting and re-rounding process for a variety of dent scenarios (i.e. depths, restraints, indenter sizes). The results of the finite element model are then used in conjunction with the estimated pressure-time history in an integrity assessment procedure to estimate the safe remaining operational life of the pipe segment. The paper presents a discussion of the full scale fatigue tests carried out on dented pipeline segments and the efforts under way to develop and validate a finite element model of the experimental specimens with the goal of estimating the experimental fatigue life.

Full Scale Cyclic Fatigue Testing of Dented Pipelines and Development of a Validated Dented Pipe Finite Element Model

2012 ◽  
Author(s):  
Sanjay Tiku ◽  
Vlado Semiga ◽  
Aaron Dinovitzer ◽  
Geoff Vignal
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fatigue Testing ◽  
Complex Function ◽  
Element Model ◽  
Full Scale ◽  
Assessment Model ◽  
Integrity Assessment ◽  
Operational Life ◽  
Integrity Management

Dents in buried pipelines can occur due to a number of potential causes; the pipe resting on rock, third party machinery strike, rock strikes during backfilling, amongst others. The long-term integrity of a dented pipeline segment is a complex function of a variety of parameters, including pipe geometry, indenter shape, dent depth, indenter support, pressure history at and following indentation. In order to estimate the safe remaining operational life of a dented pipeline, all of these factors must be accounted for in the analysis. The paper discusses the full-scale dent testing being completed to support the development of pipeline integrity management criteria and is a continuation of the work discussed in previous IPC papers [1,2]. The material and structural response of the pipe test segments during dent formation and pressure loading has been recorded to support numerical model development. The full scale experimental testing is being completed for pipe test specimens in the unrestrained and restrained condition using different indentation depths and indenter sizes. The dents are pressure cycled until fatigue failure in the dent. This paper presents typical data recorded during trial including indentation load/displacement curves, applied pressures, strain gauges along the axial and circumferential centerlines, as well as dent profiles. The use of the full-scale mechanical damage test data described in this paper in calibrating and validating a finite element model based integrity assessment model is outlined. The details of the integrity assessment model are described along with the level of agreement of the finite element model with the full scale trial results. Current and future applications of the integrity assessment model are described along with recommendations for further development and testing to support pipeline integrity management.

Full Scale Cyclic Fatigue Testing of Dented Pipelines and Development of a Validated Dented Pipe Finite Element Model

2010 ◽  
Author(s):  
Brock Bolton ◽  
Vlado Semiga ◽  
Sanjay Tiku ◽  
Aaron Dinovitzer ◽  
Joe Zhou
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fatigue Testing ◽  
Complex Function ◽  
Element Model ◽  
Full Scale ◽  
Assessment Model ◽  
Experimental Program ◽  
Integrity Assessment ◽  
Operational Life

Dents in buried pipelines can occur due to a number of potential causes; the pipe resting on rock, third party machinery strike, rock strikes during backfilling, amongst others. The long-term integrity of a dented pipeline segment is a complex function of a variety of parameters, including pipe geometry, indenter shape, dent depth, indenter support, pressure history at and following indentation. In order to estimate the safe remaining operational life of a dented pipeline, all of these factors must be accounted for in the analysis. The goal of the full scale experimental program described in this paper is to compile a database of full scale dent test results that encompasses many of the dent types seen in the field, including plain dents, dents interacting with girth and long seam welds, and dents interacting with metal loss features, in both the unrestrained and restrained condition. The dents are pressure cycled until a fatigue failure occurs in the dent. Typical data recorded includes indentation load/displacement curves, applied pressures, pipe wall OD strains along the axial and circumferential centerlines, and axial and circumferential dent profiles. The full scale tests are being performed on behalf of PRCI and US DoT. This paper is intended to show the matrix of dents considered to date and present a representative summary of the data recorded. In addition to presenting the full scale test program and resulting data, this paper summarizes ongoing efforts to develop a validated pipeline dent integrity assessment model. The model under development makes use of the aforementioned full scale experimental data, to validate a finite element model of the denting and re-rounding process for a variety of dent scenarios (i.e. depths, restraints, indenter sizes). The paper discusses the efforts under way to develop and validate the finite element model with the goal being to estimate the fatigue life. The paper is an extension of work discussed in a previously presented IPC paper [1].

scholarly journals Seismic Failure Pattern Prediction in a Historical Masonry Minaret under Different Earthquakes

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Halil Nohutcu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Nonlinear Analysis ◽  
Dynamic Characteristics ◽  
Time History ◽  
Element Model ◽  
Ambient Vibration ◽  
Tension Stress ◽  
Historical Structures ◽  
Ambient Vibration Tests

Historical structures are the values that are of great importance to that country, showing the roots of a country, and must be passed on from generation to generation. This study attempts to make a contribution to this goal. Seismic damage pattern estimation in a historical brick masonry minaret under different ground motion levels is investigated by using updated finite element models based on ambient vibration data in this study. Imaret Mosque which was built in 1481 AD is selected for an application. Surveying measurement and material tests were conducted to obtain a 3D solid model and mechanical properties of the components of the minaret. Firstly, the initial 3D finite element model of the minaret was analyzed and numerical dynamic characteristics of the minaret were obtained. Then, ambient vibration tests as well as operational modal analysis were implemented in order to obtain the experimental dynamic characteristics of the minaret. The initial finite element model of the minaret was updated by using the experimental dynamic results. Lastly, linear and nonlinear time-history analyses of the updated finite element model of the minaret were carried out using the acceleration records of two different level earthquakes that occurred in Turkey, in Afyon-Dinar (1995) and Çay-Sultandağı (2002). A concrete damage plasticity model is considered in the nonlinear analyses. The conducted analyses indicate that the compressive and tension stress results of the linear analyses are not as realistic as the nonlinear analysis results. According to the nonlinear analysis, the Çay-Sultandağı earthquake would inflict limited damage on the minaret, whereas the Dinar earthquake would damage some parts of the elements in the transition segment of the minaret.

Study on the Structural and Aseismatical Performance of Multi-Storey Ancient Chinese Timber Structure Shangyou Tower of Palace Style

2012 ◽  
Vol 535-537 ◽  
pp. 2012-2016
Author(s):  
Da Feng Gao ◽  
Peng Fei Li ◽  
Lei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ground Motion ◽  
Vibration Isolation ◽  
Time History ◽  
Element Model ◽  
Timber Structure ◽  
Wooden Frame ◽  
Spring Element ◽  
The Ancient Chinese

Based on the rich previous experimental data, the multi-storey ancient Chinese timber structure shangyou tower of palace style was studied. ANSYS10.0 software was used to establish the finite element models. One finite element model of large wooden frame was established by applying semi-rigid spring element to simulate the joint of mortise-tenon, tou-kung and the connection on column foot in the real wooden structure. The other finite element model of antique building corresponding to the finite element model above was established. The first 10 inherent frequencies and vibrations of the two models were obtained by the method of Block Lanczos with full transient analysis. The model displacement and acceleration time history curves were obtained by taking the two models subjected to El-Centro ground motion, Taft ground motion and Lanzhou artificial ground motion excitation. By the results analysis of the two models, it can be find that the vibration isolation performance of the ancient Chinese timber structure mainly manifests in the column foot, tenon and mortise connection and the tou-kung layer.

The Finite Element Model Determination in the Loess Regions under Subway Vibration Loads

2011 ◽  
Vol 368-373 ◽  
pp. 2586-2590
Author(s):  
Zhao Bo Meng ◽  
Shi Cai Cui ◽  
Teng Fei Zhao ◽  
Liu Qin Jin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Low Frequency ◽  
Time History ◽  
Ground Vibration ◽  
Element Model ◽  
Vibration Velocity

According to measured shear wave velocity of Xi’an Bell Tower area (Loess Area), the dynamic parameters of site soil are determined by using the relationship between shear wave velocity and compression wave velocity. Using Matlab program, the finite element size for low frequency subway vibration is obtained by analyzing soil dispersion phenomenon. On this basis, two-dimensional model with viscous - elastic boundaries is established by using the ANSYS program. The load-time history of the train is applied to the right tunnel, and the effects of the depth and breadth of the different models on the ground vibration velocity are discussed. Finally, the dimensions and element sizes of finite element model are obtained for the Xi'an No. 2 Metro Line with 15m depth in the loess regions.

scholarly journals Structural Response of Submerged Air-Backed Plates by Experimental and Numerical Analyses

2000 ◽  
Vol 7 (6) ◽  
pp. 333-341 ◽  
Author(s):  
Lloyd Hammond ◽  
Raphael Grzebieta
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Response ◽  
Time History ◽  
Element Model ◽  
Steel Plates ◽  
Small Scale ◽  
History Of ◽  
Structural Responses ◽  
The Finite Element Model

This paper presents the results of a series of small-scale underwater shock experiments that measured the structural responses of submerged, fully clamped, air-backed, steel plates to a range of high explosive charge sizes. The experimental results were subsequently used to validate a series of simulations using the coupled LS-DYNA/USA finite element/boundary element codes. The modelling exercise was complicated by a significant amount of local cavitation occurring in the fluid adjacent to the plate and difficulties in modelling the boundary conditions of the test plates. The finite element model results satisfactorily predicted the displacement-time history of the plate over a range of shock loadings although a less satisfactory correlation was achieved for the peak velocities. It is expected that the predictive capability of the finite element model will be significantly improved once hydrostatic initialisation can be fully utilised with the LS-DYNA/USA software.

Testing and Analysis Process of Earthquake Resistance Mainframe Computer Structure

2016 ◽  
Author(s):  
Budy Notohardjono ◽  
Richard Ecker ◽  
Shawn Canfield
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Time History ◽  
Element Model ◽  
Seismic Events ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Mainframe Computer ◽  
Computer Structure ◽  
The Finite Element Model

A mainframe computer’s structure consists of a frame or rack, drawers with central processor units, IO equipment, memory and other electronic equipment. The focus of this structural mechanical analysis and design is on the frame, earthquake stiffening brackets and tie-down methods. The primary function of the frame is to protect critical electronic equipment in two modes. The first mode is during shipping shock and vibration, which provides excitation primarily in the vertical direction. The second mode of protection is protecting the equipment during seismic events where horizontal vibration can be significant. Frame stiffening brackets and tie-downs are features added to mainframe systems that must meet earthquake resistance requirements. Designing to withstand seismic events requires significant analysis and test efforts since the functional performance of the system must be maintained during and after seismic events. The frame stiffening brackets and anchorage system must have adequate strength and stiffness to counteract earthquake-induced forces, thereby preventing human injury and potential system damage. The frame’s stiffening bracket and tie-down combination must ensure continued system operation by limiting overall displacement of the structure to acceptable levels, while not inducing undue stress to the critical electronic components. This paper discusses the process of finite element analysis and testing of a mainframe computer structure to develop a design that can withstand a severe earthquake test profile. Finite element analysis modeling tools such as ANSYS, a general-purpose finite element solver, was used to analyze the initial frame design CAD model. Both implicit and explicit finite element methods were used to analyze the mainframe subjected to uniaxial and triaxial earthquake test profiles. The seismic simulation tests involve extensive uniaxial and triaxial earthquake testing in both raised floor and non-raised floor environments at a test facility. Prior to this extensive final test, in-house tests were conducted along with modal analysis of the prototype frame hardware. These tests are used to refine the dynamic characteristics of the finite element model and to design the frame stiffening bracket and tie-down system. The purpose of the modeling and in-house testing is to have a verified finite element model of the server frame and components, which will then lead to successful, seismic system tests. During experimental verification, the dynamic responses were recorded and analyzed in both the time and frequency domains. The use of explicit finite element modeling, specifically LS-DYNA, extends the capability of implicit, linear modeling by allowing the incorporation of test data time history input and the experimentally derived damping ratio. When combined with the ability to model non-linear connections and material properties, this method provides better correlation to measured test results. In practice, the triaxial seismic time history was applied as input to the finite element model, which predicted regions of plastic strain and deformation. These results were used to iteratively simulate enhancements and successfully reduce structural failure in subsequent testing.

scholarly journals Numerical Simulations of Dynamic Behavior of Polyurea Toughened Steel Plates under Impact Loading

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chien-Chung Chen ◽  
Daniel G. Linzell
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Behavior ◽  
Impact Loading ◽  
Numerical Models ◽  
Model Development ◽  
Time History ◽  
Element Model ◽  
Steel Plates ◽  
Numerical Work

The objective of the work discussed herein is to develop a nonlinear 3D finite element model to simulate dynamic behavior of polyurea toughened steel plates under impact loading. Experimental and numerical work related to model development are presented. Material properties are incorporated into numerical models to account for strain-rate effects on the dynamic behavior of polyurea and steel. One bare steel plate and four polyurea toughened steel plates were tested under impact loading using a pendulum impact device. Displacement time-history data from experimental work was used to validate the numerical models. Details on material model construction, finite element model development, and model validation are presented and discussed. Results indicate that the developed numerical models can reasonably predict dynamic response of polyurea toughened steel plates under impact loading.

Finite Element Model Updating of Space Grid Structures

2011 ◽  
Vol 243-249 ◽  
pp. 116-119
Author(s):  
Tian Yin Xiao ◽  
Jian Gang Han ◽  
Hong Bo Gao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Numerical Models ◽  
Time History ◽  
Element Model ◽  
Vibration Test ◽  
Modal Shape ◽  
Numerical Predictions ◽  
Space Grid

The aim of updating models is to generate improved numerical models which may be applied in order to predict actual dynamic behaviors of the structure. The approach of numerical predictions to the behavior of a physical system is limited by the assumptions used in the development of the mathematical model. Model updating is about correcting invalid assumptions by processing vibration test results. Updating by improving the physical meaning of the model requires the application of considerable physical insight in the choice of parameters to update and the arrangement of constraints, force inputs and response measurements in the vibration test. The choice of updating parameters is the most important and the numerical predictions should be sensitive to small changes in the parameters. So methods used in model updating places a demand that the mass, stiffness and damping terms should be based on physically meaningful parameters. Using the structure frequency and local modal shape acquired from structural time-history responses, a model updating method of space grid structures was established in this paper. A numerical example is provided to prove the accuracy of this method. The results show that the method can be effectively used to correct the finite element model of space grid structures.

Dynamic Response Research of Ship/Jacket Platform Collision

2009 ◽  
Author(s):  
Jin Gan ◽  
Weiguo Wu ◽  
Jin Pan ◽  
Huanxiang Sun ◽  
Mengwei Zhu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Dynamic Response ◽  
Finite Element Model ◽  
Time History ◽  
Element Model ◽  
Jacket Platform ◽  
Finite Element Numerical Simulation ◽  
Simplified Finite Element Model ◽  
Local Deformations

In this paper, a new simplified finite element model is proposed for ship-jacket platform collision. This model can achieve all kinds of concerned parameters and time history curves through once calculation. This paper also discusses the effect of stain rate in ship-platform collision. On the basis of the above work, finite element numerical simulation of ship-platform collision is carried out. Some important results such as collision forces, stress, local deformations, distribution of various energies and displacement of platform are discussed. At last, some useful conclusions are achieved.

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