Evaluation of Strength of Pipe With Metal-Loss due to CUI by FFS and FEA Which Considered the Fracture Ductility

2018 ◽  
Author(s):  
Atsushi Yamaguchi ◽  
Nobuyuki Yoshida
Keyword(s):  
Ductile Fracture ◽  
Stress Condition ◽  
Experimental Results ◽  
Burst Pressure ◽  
Metal Loss ◽  
Multiaxial Stress ◽  
Element Analysis ◽  
Domestic Industry ◽  
Corrosion Under Insulation

Corrosion under insulation (CUI) is an aging degradation issue in long-term service vessels and pipes made of carbon steel and low-alloy steel. One of the problems in managing CUI is an equivocal evaluation technique of thinning detected by inspection. A replacement period with more accuracy can be evaluated more appropriately by performing fitness-for-service (FFS) assessment in this equipment. It is important to verify the validity of the FFS assessment using actually corroded pipes in order to promote the spread of FFS assessment in the domestic industry. In the present paper, pipes with complicated metal-loss due to CUI that were used in a chemical plant are burst in burst tests. An estimated burst pressure, which is calculated based on the assessment of metal-loss and through finite element analysis (FEA) based on FFS assessment, is compared with experimentally obtained burst pressures in order to validate the integrity evaluation. The burst pressure is then estimated by FEA, in which the ductile fracture under the multiaxial stress condition is considered. The burst pressure estimated by FFS approximately matched the burst pressure obtained based on experimental results. Fitness-for-service is sufficiently valid for investigating the remaining strength or burst pressure of corroded pipe. In addition, the burst pressure estimated by FEA that considered the ductile fracture under the multiaxial stress condition agreed with the experimental results and is valid so long as the remaining strength factor (RSF) is less than 0.6.

Effect of Thickness Measurement Procedure on Stress Analysis of Pipes With Local Metal Loss

2013 ◽  
Author(s):  
Nobuyuki Yoshida ◽  
Atsushi Yamaguchi
Keyword(s):  
Decision Making ◽  
Measurement Procedure ◽  
Thickness Measurement ◽  
Burst Pressure ◽  
Metal Loss ◽  
Element Analysis ◽  
Fea Model ◽  
Laser Displacement Meter ◽  
The Difference ◽  
Corrosion Under Insulation

Fitness-For-Service (FFS) assessment using Finite Element Analysis (FEA) has been a problem in deciding yes-no which vary from evaluator to evaluator. The difference in decision making is caused by the degree of freedom in modeling a FEA model. In this study, burst pressures of pipes with local metal loss were calculated by using FEA in order to investigate the influence of thickness measurement intervals on FFS assessment. The analyzed pressures by FEA were verified by burst tests. A pipe specimen, which was thinned by corrosion under insulation in the actual plant, was used for the burst tests. Shape of the pipe specimen was measured by laser displacement meter and extracted at several types of interval. It is concluded that the analyzed pressures in various measurement intervals showed almost no difference, but were higher than the actual burst pressure of the specimen.

Evaluating Dents With Metal Loss Using Finite Element Analysis

2016 ◽  
Author(s):  
Justin Gossard ◽  
Joseph Bratton ◽  
David Kemp ◽  
Shane Finneran ◽  
Steven J. Polasik
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Laser Scanner ◽  
Mechanical Damage ◽  
Third Party ◽  
Burst Pressure ◽  
Metal Loss ◽  
Surface Mesh ◽  
Element Analysis ◽  
3D Surface

Dents created by third party mechanical damage are a severe integrity threat to onshore and offshore transmission pipelines. This type of damage is often associated with metal loss, which can be introduced during the initiation of a dent or develop as a result of the presence of a dent and associated coating damage. Once a dent has been found to be associated with metal loss through excavation, there is little guidance to determine the serviceability of the anomaly. In this study, dents with associated metal loss due to corrosion examined in the field are evaluated to determine the contribution of the interacting dent and metal loss features to the associated burst pressure of the feature. Twenty dents with metal loss flaws were identified through an ILI survey while in service to capture dimensions of the dent and metal loss features. Each site was excavated and measured using a laser scanner. The laser scanner produced 3D imaging with sufficient resolution of both the dent and metal loss areas as a 3D surface mesh. The 3D surface mesh was transformed into a 3D solid mesh and analyzed using a finite element analysis software package in order to determine a predicted internal pressure that would cause failure. A subsequent statistical assessment was performed to analyze the relationship between the ILI measurements and the predicted burst pressure resulting from finite element analysis of each dent with metal loss feature. Statistical analyses were used to evaluate the prediction capabilities of burst pressures of dent with metal loss features identified through ILI, prior to excavation and direct examination.

Evaluation of Hole Flangeability of Steel Sheet with Respect to the Hole Processing Condition

2007 ◽  
Vol 340-341 ◽  
pp. 665-670 ◽  
Author(s):  
Jong Sup Lee ◽  
Yoon Ki Ko ◽  
Hoon Huh ◽  
Hong Ki Kim ◽  
Sung Ho Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ductile Fracture ◽  
Steel Sheet ◽  
Fracture Criterion ◽  
Processing Condition ◽  
Experimental Results ◽  
Ductile Fracture Criterion ◽  
Element Analysis ◽  
Hole Flanging

This paper is concerned with hole flangeability of steel sheet, which is evaluated by experiment and finite element analysis with respect to the hole processing condition. The hole flangeability of a material as a forming limit needs to be verified to predict and prevent the undesirable fracture during a flanging process. Hole expanding tests are carried out to identify the effect of hole processing conditions on the hole expanding ratio (HER), which is an indicator of the hole flangeability. Specimens with two different hole conditions are prepared: one is produced with punching process; and the other is reamed after punching to get smoother hole surface. Experimental results show that the facture mechanism and the HER are quite different with respect to the hole conditions. Thorough investigation of those effects is carried out with tensile tests of a specimen with notches. From the experiments, the fracture strain is obtained with different hole conditions and is used to determine the material constants of a new proposed ductile fracture criterion which is applied to finite element analyses of the hole flanging process for prediction of the HER. The experimental results are confirmed and reevaluated by the finite element analysis with the ductile fracture criterion.

Evaluating the Effects of Wrinkle Bends on Pipeline Integrity

2008 ◽  
Author(s):  
Chris Alexander ◽  
Satish Kulkarni
Keyword(s):  
El Paso ◽  
Fatigue Tests ◽  
Life Extension ◽  
Metal Loss ◽  
Pipeline System ◽  
Strain Gages ◽  
Element Analysis ◽  
Repair Materials ◽  
Cycles To Failure

Concerns exist among the pipeline industry about the effects of wrinkle bends on the long-term integrity of pipelines. For this reason, a study was sponsored to assess the relative severity of wrinkle bends present in the El Paso pipeline system. The study involved a combination of full-scale cyclic pressure fatigue tests, along with finite element analysis, to determine cycles to failure. Strain gages were installed on select samples to determine alternating stresses. Also included in the study was installation of E-glass composite repair materials (Armor Plate® Pipe Wrap) on selected wrinkles to determine the potential for life extension considering the presence of reinforcement. The study helped in developing “in-the-ditch” evaluation criterion and a tool to determine the severity of a specific wrinkle bend based on geometric parameters including wrinkle height and length. The effects of metal loss due to corrosion were also considered. Additionally, the experimental results demonstrated that composite materials can extend the fatigue life of wrinkle bends.

scholarly journals Compact Heat Exchanger Semi-Circular Header Burst Pressure and Strain Validation

2019 ◽  
Author(s):  
Blake W. Lance ◽  
Matthew D. Carlson
Keyword(s):  
Accuracy Assessment ◽  
Two Dimensions ◽  
Experimental Results ◽  
Image Correlation ◽  
Burst Pressure ◽  
Element Analysis ◽  
Simulation Accuracy ◽  
The Rich ◽  
Rich Data ◽  
Deformation Measurements

Abstract Compact heat exchangers for supercritical CO2 (sCO2) service are often designed with external, semi-circular headers. Their design is governed by the ASME Boiler & Pressure Vessel Code (BPVC) whose equations were typically derived by following Castigliano’s Theorems. However, there are no known validation experiments to support their claims of pressure rating or burst pressure predictions nor is there much information about how and where failures occur. This work includes high pressure bursting of three semi-circular header prototypes for the validation of three aspects: (1) burst pressure predictions from the BPVC, (2) strain predictions from Finite Element Analysis (FEA), and (3) deformation from FEA. The header prototypes were designed with geometry and weld specifications from the BPVC Section VIII Division 1, a design pressure typical of sCO2 service of 3,900 psi (26.9 MPa), and were built with 316 SS. Repeating the test in triplicate allows for greater confidence in the experimental results and enables data averaging. Burst pressure predictions are compared with experimental results for accuracy assessment. The prototypes are analyzed to understand their failure mechanism and locations. Experimental strain and deformation measurements were obtained optically with Digital Image Correlation (DIC). This technique allows strain to be measured in two dimensions and even allows for deformation measurements, all without contacting the prototype. Eight cameras are used for full coverage of both headers on the prototypes. The rich data from this technique are an excellent validation source for FEA strain and deformation predictions. Experimental data and simulation predictions are compared to assess simulation accuracy.

scholarly journals Influence of Circumferential Flaw Length on Internal Burst Pressure of a Wall-Thinned Pipe

2012 ◽  
Author(s):  
Masataka Tsuji ◽  
Toshiyuki Meshii
Keyword(s):  
Finite Element Analysis ◽  
Fracture Mode ◽  
Experimental Results ◽  
The Other ◽  
Burst Pressure ◽  
Test Results ◽  
Element Analysis ◽  
Burst Test ◽  
Axial Crack ◽  
Planar Flaw

The effect of the circumferential angle of a flaw θ on the internal burst pressure pf of pipes with artificial wall-thinned flaws is examined. When evaluating pf of wall-thinned straight pipes, the effect of θ has been conventionally not regarded as important. Therefore, a burst pressure equation for an axial crack inside a cylinder (Fig. 1, left), such as Kiefner’s equation [1] is widely used [2], [3]. However, it should be noted that there exist the following implicit assumptions when applying the equation for planar flaws to non-planar flaws. 1) The fracture mode of a non-planar flaw under consideration is identical with that of the crack. 2) The effect of θ, which is not considered for an axial crack on pf, is small or negligible. However, from the systematic burst test results of carbon pipes with artificial wall-thinned flaws, Meshii [4] showed that these implicit assumptions may not be correct. On the other hand, the significance of the effect of the fracture mode on pf and the condition for θ to affect pf are not clear. Therefore, in this paper, Meshii’s experimental results are evaluated in farther detail. The purpose of the evaluation was set to clarify the effect of θ on pf. Specifically, the significance of flaw configuration (axial length δz and wall-thinning ratio t1/t) was studied in relation to θ and pf. In addition, a simulation of the effect by a Finite Element Analysis (FEA) was attempted. From the experimental results, θ tended to affect pf in cases with large δz, and t1/t also was correlated to a decrease in pf with the increase of θ. These tendencies were successfully simulated by the elastic-plastic FEA. This effect means the burst pressure predicted for a crack with identical ligament thickness decreases with the increase of θ, so that the effect by θ on pf should not be ignored.

Tire Cornering Simulation Using an Explicit Finite Element Analysis Code

1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test System ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Element Method

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.

scholarly journals Experimental and Analytical Study on Creep Characteristics of Box Section Bamboo-Steel Composite Columns under Long-Term Loading

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 983
Author(s):  
Shixu Wu ◽  
Keting Tong ◽  
Jianmin Wang ◽  
Yushun Li
Keyword(s):  
Load Level ◽  
Experimental Results ◽  
Creep Model ◽  
Composite Column ◽  
Composite Columns ◽  
Creep Coefficient ◽  
Creep Characteristics ◽  
Section Size ◽  
Steel Composite

To expand the application of bamboo as a building material, a new type of box section composite column that combined bamboo and steel was considered in this paper. The creep characteristics of eight bamboo-steel composite columns with different parameters were tested to evaluate the effects of load level, section size and interface type under long-term loading. Then, the deformation development of the composite column under long-term loading was observed and analyzed. In addition, the creep-time relationship curve and the creep coefficient were created. Furthermore, the creep model of the composite column was proposed based on the relationship between the creep of the composite column and the creep of bamboo, and the calculated value of creep was compared with the experimental value. The experimental results showed that the creep development of the composite column was fast at first, and then became stable after about 90 days. The creep characteristics were mainly affected by long-term load level and section size. The creep coefficient was between 0.160 and 0.190. Moreover, the creep model proposed in this paper was applicable to predict the creep development of bamboo-steel composite columns. The calculation results were in good agreement with the experimental results.

Influence of Permeability on the Compressive Property of Articular Cartilage: A Scaffold-Free, Stem Cell-Based Therapy for Cartilage Repair

2011 ◽  
Author(s):  
Tomoya Susa ◽  
Ryosuke Nansai ◽  
Norimasa Nakamura ◽  
Hiromichi Fujie
Keyword(s):  
Articular Cartilage ◽  
Superficial Layer ◽  
Cell Delivery ◽  
Compressive Property ◽  
Chondral Defect ◽  
Element Analysis ◽  
Normal Cartilage ◽  
Cell Based Therapy ◽  
Immunological Effects

Since the healing capacity of articular cartilage is limited, it is important to develop cell-based therapies for the repair of cartilage. Although synthetic or animal-derived scaffolds are frequently used for effective cell delivery long-term safety and efficiency of such scaffolds still remain unclear. We have been studying on a scaffold-free tissue engineered construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs) [1]. As the TEC specimen is composed of cells with their native extracellular matrix, we believe that it is free from concern regarding long term immunological effects. our previous studies indicated that a porcine partial thickness chondral defect was successfully repaired with TEC but that the compressive property of the TEC-treated cartilage-like repaired tissue was different from normal cartilage in both immature and mature animals. Imura et al. found that the permeability of the immature porcine cartilage-like tissues repaired with TEC recovered to normal level for 6 months except the superficial layer [2]. Therefore, the present study was performed to determine the depth-dependent permeability of mature porcine cartilage-like tissue repaired with TEC. Moreover, we investigated the effect of difference of permeability on the compressive property of articular cartilage using a finite element analysis (FEM).

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