Pattern Studies of the Strain Distributions for Detecting Pipe Wrinkling

2010 ◽  
Author(s):  
Z. L. Chou ◽  
J. J. R. Cheng ◽  
Joe Zhou
Keyword(s):  
Strain Distribution ◽  
Local Buckling ◽  
Arctic Region ◽  
Distribution Patterns ◽  
Buried Pipelines ◽  
Element Analysis ◽  
Behavioural Characteristics ◽  
Decision Making System ◽  
Parametric Studies ◽  
Buckling Failure

As both the onshore and offshore pipeline constructions push further into higher risk terrains, such as geologically unstable terrain and Arctic region, the risk of local buckling failure (wrinkling) for these buried pipelines has been increasing gradually. However, previous methods used to prevent the buried pipelines from buckling failure are expansive, time consuming, and unreliable. Therefore, to overcome these problems, a reliable method to predict pipeline wrinkling has been proposed. The method can provide active warning for pipeline wrinkling through a decision-making system (DMS). The DMS was designed to identify the strain distribution patterns and their development on the critical pipe segments for early detecting the onset of pipe wrinkling. To conduct the reliable DMS, studies of the strain distribution patterns on the line-pipes during pipe buckling are very important. In this paper, the strain distribution patterns of various line-pipes were presented. These line-pipes have different material and geometric properties, loading conditions, and manufacturing conditions. A total of 32 sets of experimental results and 72 sets of finite element analysis (FEA) along with parametric studies were included in the study. The study concluded significant behavioural characteristics revealed on the strain distribution patterns during pipe buckling and important parameters affecting these strain patterns. For practical application, three thresholds of the strain distribution patterns were proposed. Furthermore, the optimal positions and spacing of the strain measurements for early detecting pipelines wrinkling were discussed as well.

Pattern Studies of Strain Distributions for Detecting Pipe Wrinkling

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Z. L. Chou ◽  
J. J. R. Cheng ◽  
J. Zhou
Keyword(s):  
Strain Distribution ◽  
Local Buckling ◽  
Arctic Region ◽  
Distribution Patterns ◽  
The Arctic ◽  
Buried Pipelines ◽  
Offshore Pipeline ◽  
Decision Making System ◽  
Parametric Studies ◽  
Buckling Failure

As both onshore and offshore pipeline constructions push further into higher risk terrains, such as geologically unstable terrain and the Arctic region, the risk of local buckling failure (wrinkling) for these buried pipelines has been increasing gradually. However, current methods used to prevent buried pipelines from buckling failure are expensive, time consuming, and unreliable. Therefore, to overcome these problems, a reliable method of predicting pipeline wrinkling is proposed. The method can provide active warning for pipeline wrinkling through a decision-making system (DMS). The DMS has been designed to identify strain distribution patterns and their development on critical pipe segments and detect the onset of pipe wrinkling. To create a reliable DMS, studies of the strain distribution patterns of line-pipes during pipe buckling are very important. In this paper, the strain distribution patterns of various line-pipes are presented. These line-pipes have different material and geometric properties, loading conditions, and manufacturing conditions. A total of 32 sets of experimental results and 72 sets of finite element analyses (FEA) along with parametric studies were included in the study. The study revealed significant behavioral characteristics of the strain distribution patterns during pipe buckling and important parameters affecting these strain patterns. For practical application, three thresholds of the strain distribution patterns are proposed. Furthermore, the optimal positions and spacing of the strain measurements for early detecting pipelines wrinkling are discussed as well.

Comparative Stress Distribution of Implant-Retained Mandibular Ball-Supported and Bar-Supported Overlay Dentures: A Finite Element Analysis

2011 ◽  
Vol 37 (4) ◽  
pp. 421-429 ◽  
Author(s):  
Fariborz Vafaei ◽  
Masoumeh Khoshhal ◽  
Saeed Bayat-Movahed ◽  
Ahmad Hassan Ahangary ◽  
Farnaz Firooz ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Strain Distribution ◽  
Treatment Options ◽  
Three Dimensional ◽  
Distribution Patterns ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Second Molar ◽  
Edentulous Mandible ◽  
Tomography Scan

Abstract Implant-retained mandibular ball-supported and bar-supported overlay dentures are the two most common treatment options for the edentulous mandible. The superior option in terms of strain distribution should be determined. The three-dimensional model of mandible (based on computerized tomography scan) and its overlying implant-retained bar-supported and ball-supported overlay dentures were simulated using SolidWorks, NURBS, and ANSYS Workbench. Loads A (60 N) and B (60 N) were exerted, respectively, in protrusive and laterotrusive motions, on second molar mesial, first molar mesial, and first premolar. The strain distribution patterns were assessed on (1) implant tissue, (2) first implant-bone, and (3) second implant-bone interfaces. Protrusive: Strain was mostly detected in the apical of the fixtures and least in the cervical when bar design was used. On the nonworking side, however, strain was higher in the cervical and lower in the apical compared with the working side implant. Laterotrusive: The strain values were closely similar in the two designs. It seems that both designs are acceptable in terms of stress distribution, although a superior pattern is associated with the application of bar design in protrusive motion.

Analytical Simulation and Field Measurements for a Wrinkle on the Norman Wells Pipeline

2000 ◽  
Author(s):  
Nader Yoosef-Ghodsi ◽  
J. J. Roger Cheng ◽  
David W. Murray ◽  
Rick Doblanko ◽  
Scott Wilkie
Keyword(s):  
Large Deformations ◽  
Local Buckling ◽  
Field Measurements ◽  
Interesting Case ◽  
Buried Pipelines ◽  
Element Analysis ◽  
Field Evidence ◽  
Analytical Simulation ◽  
Geotechnical Investigations ◽  
Additional Testing

In laboratory testing of full-sized pipe subjected to combined axial load, internal pressure and bending, the normal failure mode consists of local buckling on the side of the maximum compressive fiber. If loading is continued beyond the initiation of buckling, and if the pipe is pressurized internally, the pipe retains its integrity while it develops a wrinkle in which very large deformations occur. Buried pipelines should behave in the same way. The paper presents the analyses carried out to assist in the interpretation of Geopig field evidence that, in September of 1997, a wrinkle existed on Slope 92 on the Norman-Wells Pipeline. A finite element analysis of a shell model of a segment of the pipe confirmed that the wrinkle should exist. A subsequent pipe dig uncovered the wrinkle which had a configuration remarkably similar to those observed in the laboratory and to the form predicted by the analysis. Supplementary geotechnical investigations, a review of operational procedures on the line, and additional testing to determine strains within wrinkles, are presented in companion papers elsewhere in this conference. These combined papers provide a thorough documentation relative to this most interesting case history.

An Evaluation Method for Plastic Buckling of Cantilever Type Pipes Controlled by Displacement Loads: Part 2—Verification of Proposal Method by Buckling Test

2011 ◽  
Author(s):  
Masanori Ando ◽  
Taiji Tezuka ◽  
Toshio Nakamura ◽  
Tomohiro Okawa ◽  
Yasuhiro Enuma ◽  
...  
Keyword(s):  
Strain Distribution ◽  
Evaluation Method ◽  
Estimation Method ◽  
Local Buckling ◽  
Design Rule ◽  
Element Analysis ◽  
Piping Systems ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Buckling Test

In Fast Breeder Reactors, dominant stresses in the system are secondary, which are induced by constraint of the thermal expansion of components and pipes. Therefore, the structural design rule should essentially prevent the buckling caused by displacement-controlled loads. In this paper the applicability of the estimation method of buckling criterion, which was proposed by the authors on the basis of a series of Finite Element Analysis (FEA), was confirmed by carrying out a series of buckling tests. The displacement-controlled buckling tests were performed with cantilever type pipes made of Mod.9Cr-1Mo steel at room temperature and at 550°C. A visual measurement using image processing was applied to clarify both deformation profile and strain distribution at the local buckling portion of pipes. FEA was used in advance for estimating the buckling behavior of tests, such as load-displacement relationship, deformation profile and longitudinal strain distribution. Comparison between test and FEA results showed that buckling behaviors in the tests are predictable by FEA. The estimation method of buckling criterion on the basis of FEA was found to conservatively cover the test results, and we can conclude that this estimation method can be adopted for designing the piping systems of Fast Breeder Reactors.

scholarly journals Permodelan Pengekangan Kolom Pada Beton Mutu Normal Dengan Metode Elemen Hingga 3-D

2020 ◽  
Vol 8 (2) ◽  
pp. 104-115
Author(s):  
Ridho Saleh Silaban ◽  
Darmansyah Tjitradi ◽  
Syahril Taufik
Keyword(s):  
Strain Distribution ◽  
Axial Load ◽  
Axial Loading ◽  
Distribution Patterns ◽  
Critical Element ◽  
Axial Deformation ◽  
Working Pressure ◽  
Element Analysis ◽  
Short Columns ◽  
Concrete Elements

The column is a critical element in the building structure, the failure of the column will directly result in the collapse of other related structural components. The column must have strength, stability and ductility. In increasing the capacity and ductility of the column by providing confinement, to protect concrete elements from breaking due to the influence of the working pressure. Analyzing ultimate axial load capability, stress-strain distribution patterns and crack patterns in concrete elements and column ductility. Tests of several models and variations of the restraint distance in short columns of normal concrete quality with longitudinal reinforcement of steel steels and carbon steel transversal reinforcement. The columns were analyzed using the Finite Element Analysis (FEA) method with the help of a full scale ANSYS 3-D application, with material properties for concrete using SOLID65 and steel reinforcement using LINK8 and SOLID45 loading plates. The type of pedestal used is the joints with axial loading (axial loadstep) centric direction. The effect of the restraint model and the variation of the restraint distance to the value of the column ultimate axial load for the whole model is relatively small with a ratio of 1.079, while for the ratio of the axial deformation ratio of 1.496. The pattern of stress and strain distribution when yielding spreads throughout the column area but when it reaches the ultimate distribution the concentration is concentrated in the support area. The first dominant crack occurs in the pedestal area and generally occurs in the concrete blanket layer, in the ultimate condition cracks have occurred evenly throughout the column area. The ratio of the ratio of ductility values ??for all column models and the restraint distance is relatively large with a ratio value of 1.523

scholarly journals A Finite Element Study on Compressive Resistance Degradation of Square and Circular Steel Braces under Axial Cyclic Loading

2021 ◽  
Vol 11 (13) ◽  
pp. 6094
Author(s):  
Hubdar Hussain ◽  
Xiangyu Gao ◽  
Anqi Shi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cyclic Loading ◽  
Slenderness Ratio ◽  
Hysteretic Behavior ◽  
Element Analysis ◽  
Section Shape ◽  
Axial Cyclic Loading ◽  
Global Buckling ◽  
Parametric Studies

In this study, detailed finite element analysis was conducted to examine the seismic performance of square and circular hollow steel braces under axial cyclic loading. Finite element models of braces were constructed using ABAQUS finite element analysis (FEA) software and validated with experimental results from previous papers to expand the specimen’s matrix. The influences of cross-section shape, slenderness ratio, and width/diameter-to-thickness ratio on hysteretic behavior and compressive-tensile strength degradation were studied. Simulation results of parametric studies show that both square and circular hollow braces have a better cyclic performance with smaller slenderness and width/diameter-to-thickness ratios, and their compressive-tensile resistances ratio significantly decreases from cycle to cycle after the occurrence of the global buckling of braces.

scholarly journals Locally Corroded Stiffener Effect on Shear Buckling Behaviors of Web Panel in the Plate Girder

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Jungwon Huh ◽  
In-Tae Kim ◽  
Jin-Hee Ahn
Keyword(s):  
Corrosion Damage ◽  
Element Analysis ◽  
Buckling Strength ◽  
Lower Shear ◽  
Out Of Plane ◽  
Shear Buckling ◽  
Buckling Failure ◽  
Plane Displacement ◽  
The Web ◽  
Plate Girder

The shear buckling failure and strength of a web panel stiffened by stiffeners with corrosion damage were examined according to the degree of corrosion of the stiffeners, using the finite element analysis method. For this purpose, a plate girder with a four-panel web girder stiffened by vertical and longitudinal stiffeners was selected, and its deformable behaviors and the principal stress distribution of the web panel at the shear buckling strength of the web were compared after their post-shear buckling behaviors, as well as their out-of-plane displacement, to evaluate the effect of the stiffener in the web panel on the shear buckling failure. Their critical shear buckling load and shear buckling strength were also examined. The FE analyses showed that their typical shear buckling failures were affected by the structural relationship between the web panel and each stiffener in the plate girder, to resist shear buckling of the web panel. Their critical shear buckling loads decreased from 82% to 59%, and their shear buckling strength decreased from 88% to 76%, due to the effect of corrosion of the stiffeners on their shear buckling behavior. Thus, especially in cases with over 40% corrosion damage of the vertical stiffener, they can have lower shear buckling strength than their design level.

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