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].

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.

Use of DNVGL-RP-C203 for Determining the Fatigue Capacity of Connectors

2021 ◽  
Author(s):  
Anthony Muff ◽  
Anders Wormsen ◽  
Torfinn Hørte ◽  
Arne Fjeldstad ◽  
Per Osen ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Experimental Testing ◽  
High Strength ◽  
Element Model ◽  
Fatigue Analysis ◽  
Full Scale ◽  
The Finite Element Model

Abstract Guidance for determining a S-N based fatigue capacity (safe life design) for preloaded connectors is included in Section 5.4 of the 2019 edition of DNVGL-RP-C203 (C203-2019). This section includes guidance on the finite element model representation, finite element based fatigue analysis and determination of the connector design fatigue capacity by use of one of the following methods: Method 1 by FEA based fatigue analysis, Method 2 by FEA based fatigue analysis and experimental testing and Method 3 by full-scale connector fatigue testing. The FEA based fatigue analysis makes use of Appendix D.2 in C203-2019 (“S-N curves for high strength steel applications for subsea”). Practical use of Section 5.4 is illustrated with a case study of a fatigue tested wellhead profile connector segment test. Further developments of Section 5.4 of C203-2019 are proposed. This included acceptance criteria for use of a segment test to validate the FEA based fatigue analysis of a full-scale preloaded connector.

scholarly journals Analysis of the Effect of Tungsten Inert Gas Welding Sequences on Residual Stress and Distortion of CFETR Vacuum Vessel Using Finite Element Simulations

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 912 ◽  
Author(s):  
Jingwen Zhang ◽  
Liming Yu ◽  
Yongchang Liu ◽  
Zongqing Ma ◽  
Huijun Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Full Scale ◽  
Inert Gas ◽  
Vacuum Vessel ◽  
Lower Segment ◽  
Welding Stress ◽  
Welding Sequence ◽  
Welding Sequences

The as-welded sectors of China Fusion Engineering Testing Reactor (CFETR) vacuum vessel (VV) have very tight tolerances. However, it is difficult to investigate the welding stress and distortion without the production of a full-scale prototype. Therefore, it is important to predict and reduce the welding stress and distortion to guarantee the final assembly by using an accurately adjusted finite element model. In this paper, a full-scale finite element model of the 1/32 VV mock-up was built by ABAQUS which is a powerful finite element software for engineering simulation, and three different tungsten inert gas (TIG) welding sequences were simulated to study the effect of welding sequences on the welding stress and distortion. The results showed that the main welding stress happened on the weld zone, and the maximum distortion occurred on the shell near the welding joints between the inboard segment (PS1) and the lower segment (PS4). The inboard segment (PS1), upper segment (PS2), and lower segment (PS4) distorted to inside of the shell perpendicularly, while the equatorial segment (PS3) distorted to outside of the shell perpendicularly. According to the further analysis, the maximum welding stresses in sequence 1, sequence 2, and sequence 3 were 234.509 MPa, 234.731 MPa, and 234.508 MPa, respectively, and the average welding stresses were 117.268 MPa, 117.367 MPa, and 117.241 MPa, respectively, meanwhile, the maximum welding displacements in sequence 1, sequence 2, and sequence 3 were 1.158 mm, 1.157 mm, and 1.149 mm, respectively, and the average welding displacements were 1.048 mm, 1.053 mm, and 1.042 mm, respectively. Thus, an optimized welding sequence 3 was obtained and could be applied to the practical assembly process of the 1/32 VV mock-up.

Improved Pipeline Dent Integrity Management

2016 ◽  
Author(s):  
Sanjay Tiku ◽  
Amin Eshraghi ◽  
Vlad Semiga ◽  
Luis Torres ◽  
Mark Piazza
Keyword(s):  
Numerical Simulation ◽  
Fatigue Life ◽  
Fatigue Testing ◽  
Assessment Model ◽  
Third Party ◽  
Operating Pressure ◽  
Integrity Assessment ◽  
Integrity Management ◽  
Further Development ◽  
Dent Depth

Pipeline dents can be developed from the pipe resting on rock, a third party machinery strike, rock strikes during backfilling, amongst other causes. The long-term integrity of a dented pipeline segment depends upon parameters including pipe geometry, indenter shape, dent depth, indenter support, secondary features, and pipeline operating pressure history at and following indentation. US DoT and other standards include dent repair and remediation criteria broadly based upon dent depth, dent location (top or bottom side), pressure cycling (liquid or gas), and dent interaction with secondary features (weld, corrosion, cracks). These criteria are simple and easily applied, however, they may not direct maintenance appropriately and be overly conservative or, in some cases, unconservative. Previous IPC papers have discussed the full-scale dent fatigue testing and dent modelling efforts to support integrity management criteria development by collecting material and structural response during dent formation and pressure loading. The present paper will present the results of this extensive dent structural and fatigue life numerical simulation program using a validated finite element (FE) analysis process. The paper describes the numerical simulation technique, as well as, the development of the novel engineering tool for integrity management, eliminating the need for numerical simulation of individual dent features to assess the relative integrity threat they pose. The development of the engineering tool presented in this paper considers the dent formation, re-rounding and through life response to pressure fluctuations to evaluate the fatigue life of dent features. The results of these analyses are used to develop fatigue life trends based on dent shape, restraint condition and operating pressure. These trends were used to develop models to predict dent relative severity and life based upon ILI inspection dent shape data for single peak dents. Dent shape has also been used to determine the restraint condition of a dent and its influence on the dent feature fatigue life. The tools were developed to address many of the uncertainties inherent in existing regulatory repair and remediation criteria. Current and future applications of the integrity assessment model are described along with recommendations for further development and testing to support pipeline integrity management, industry guidelines and standards. The results of this research will be of use in improving integrity management decisions and support further development of industry guides and standards. As such the information presented in this paper will be of interest to pipeline operators, integrity management specialists, in-line inspection (ILI) organizations and regulators. The recommendations presented in this paper may be used to influence the direction of pipeline standards in their direction in the disposition of dent features.

scholarly journals Updating Finite Element Model of a Wind Turbine Blade Section Using Experimental Modal Analysis Results

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Marcin Luczak ◽  
Simone Manzato ◽  
Bart Peeters ◽  
Kim Branner ◽  
Peter Berring ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Numerical Study ◽  
Element Model ◽  
Full Scale ◽  
Wind Turbine Blade ◽  
Model Parameters ◽  
Blade Section

This paper presents selected results and aspects of the multidisciplinary and interdisciplinary research oriented for the experimental and numerical study of the structural dynamics of a bend-twist coupled full scale section of a wind turbine blade structure. The main goal of the conducted research is to validate finite element model of the modified wind turbine blade section mounted in the flexible support structure accordingly to the experimental results. Bend-twist coupling was implemented by adding angled unidirectional layers on the suction and pressure side of the blade. Dynamic test and simulations were performed on a section of a full scale wind turbine blade provided by Vestas Wind Systems A/S. The numerical results are compared to the experimental measurements and the discrepancies are assessed by natural frequency difference and modal assurance criterion. Based on sensitivity analysis, set of model parameters was selected for the model updating process. Design of experiment and response surface method was implemented to find values of model parameters yielding results closest to the experimental. The updated finite element model is producing results more consistent with the measurement outcomes.

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