End Boundary Effects on Local Buckling Response of High Strength Linepipe

2010 ◽  
Author(s):  
Ali Fatemi ◽  
Shawn Kenny ◽  
Farid Taheri ◽  
Da-Ming Duan ◽  
Joe Zhou
Keyword(s):  
Finite Element ◽  
Yield Stress ◽  
Large Scale ◽  
Stress Ratio ◽  
Compressive Strain ◽  
Local Buckling ◽  
High Strength ◽  
End Effects ◽  
Industry Practice ◽  
Post Buckling

In this paper, the significance of the length to diameter ratio (L/D) on the local buckling response was evaluated using continuum finite element modelling procedures. A numerical model was developed, using the finite-element simulator ABAQUS/Standard, to predict the local buckling and post-buckling response of high strength pipelines subject to combined state of loading. The numerical procedures were calibrated using test data from large-scale experiments examining the local buckling of high strength linepipe. The numerical model’s response was consistent with the measured experimental response for predicting the local buckling behavior well into the post-yield range. A parametric study was conducted to examine the significance of the linepipe L/D ratio with respect to the yield stress to ultimate stress ratio (Y/T) and hoop yield stress to longitudinal yield stress ratio or anisotropy factor (R). As the models with high L/D ratio exhibit global Euler-type response, a numerical algorithm was developed to calculate the local section moment response for the FE analysis. The analysis conducted provides insight on the significance of end effects on the local buckling response. There are questions on the approach taken by current industry practice with respect to establishing compressive strain limits for local buckling when using shorter linepipe segment lengths. The results from this study suggest end effects require assessment and potential mitigation.

Investigations on the Local Buckling Response of High Strength Linepipe

2008 ◽  
Author(s):  
Ali Fatemi ◽  
Shawn Kenny ◽  
Millan Sen ◽  
Joe Zhou ◽  
Farid Taheri ◽  
...  
Keyword(s):  
Large Scale ◽  
Local Buckling ◽  
High Strength ◽  
Order Effects ◽  
Geometric Imperfections ◽  
Mesh Topology ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Element Simulator ◽  
Experimental Response

A numerical modeling procedure was developed, using the finite-element simulator ABAQUS/Standard, to predict the local buckling and post-buckling response of high strength pipelines subject to combined state of loading. The numerical procedures were calibrated using test data from large-scale experiments examining the local buckling of high strength linepipe. The numerical model’s response was consistent with the measured experimental response for predicting the local buckling behavior well into the post-yield range. A parametric study was conducted that examined element selection, mesh topology, second-order effects, geometric imperfections and material properties. The results from this study are presented.

Study on the Local Buckling Behavior of Steel Equal Angle Members under Axial Compression with the Steel Strength Variation

2011 ◽  
Vol 374-377 ◽  
pp. 2430-2436
Author(s):  
Gang Shi ◽  
Zhao Liu ◽  
Yong Zhang ◽  
Yong Jiu Shi ◽  
Yuan Qing Wang
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
High Strength Steel ◽  
Local Buckling ◽  
Steel Structures ◽  
High Strength ◽  
Element Analysis ◽  
Equal Angle ◽  
Buckling Behavior ◽  
Steel Strength

High strength steel sections have been increasingly used in buildings and bridges, and steel angles have also been widely used in many steel structures, especially in transmission towers and long span trusses. However, high strength steel exhibits mechanical properties that are quite different from ordinary strength steel, and hence, the local buckling behavior of steel equal angle members under axial compression varies with the steel strength. However, there is a lack of research on the relationship of the local buckling behavior of steel equal angle members under axial compression with the steel strength. A finite element model is developed in this paper to analyze the local buckling behavior of steel equal angle members under axial compression, and study its relationship with the steel strength and the width-to-thickness ratio of the angle leg. The finite element analysis (FEA) results are compared with the corresponding design method in the American code AISC 360-05, which provides a reference for the related design.

scholarly journals Validation of the load-bearing capacity of the frame assembly of metal structures on the standard 2.440 series using IDEA StatiCa

2020 ◽  
Vol 10 (3) ◽  
pp. 406-419
Author(s):  
Denis A. Melnikov ◽  
◽  
Tatyana L. Dmitrieva ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Sections ◽  
Limit State ◽  
Local Buckling ◽  
High Strength ◽  
Software Systems ◽  
Rigid Frame ◽  
Welding Forces ◽  
Element Method

The paper aims to study the actual operation of a rigid frame unit for coupling a crossbar with a column on high-strength bolts according to the standard 2.440-2 series using modern software systems of the component finite element method. Special attention was paid to the operation of nodal elements, as well as their stress-strain state. Based on the results of static calculations, the cross-sections of the elements under consideration, as well as the components of the node (plates, bolts, seams, etc.) were selected from the tables of the standard series. Subsequently, using the component finite element method serving as the basis of the IDEA StatiСa software, all the components of the node were mod-elled with respect to acting forces. The conducted calculations confirmed the suitability of the obtained node model for identifying inconsistencies in the series and modern standards. Using stresses on plates, bolt and welding forces, as well as several forms of vibration to assess the stability of compo-nents, the applicability of the node in question in the proposed configuration was evaluated. It turned out that the node failed to meet modern standards in terms of design conditions. Moreover, the serial bolts were overloaded by almost 38%, and some welds approached the limit state. When used in real conditions, this can lead to serious losses, including human lives. Recommendations are given for changing the specific configuration of the node in order to protect it from the destruction of any nature, including local buckling failure.

Remaining Local Buckling Resistance of Corroded Pipelines

2010 ◽  
Author(s):  
Qishi Chen ◽  
Heng Aik Khoo ◽  
Roger Cheng ◽  
Joe Zhou
Keyword(s):  
Finite Element ◽  
Wall Thickness ◽  
Phase 1 ◽  
Compressive Strain ◽  
Research Work ◽  
Local Buckling ◽  
Model Verification ◽  
Metal Loss ◽  
General Corrosion ◽  
Buckling Resistance

This paper describes a multi-year PRCI research program that investigated the local buckling (or wrinkling) of onshore pipelines with metal-loss corrosion. The dependence of local buckling resistance on wall thickness suggests that metal-loss defects will considerably reduce such resistance. Due to the lack of experimental data, overly conservative assumptions such as a uniform wall thickness reduction over the entire pipe circumference based on the defect depth have been used in practice. The objective of this research work was to develop local buckling criteria for pipelines with corrosion defects. The work related to local buckling was carried out in three phases by C-FER and the University of Alberta. The first phase included a comprehensive finite element analysis to evaluate the influence of various corrosion defect features and to rank key parameters. Based on the outcome of Phase 1 work, a test matrix was developed and ten full-scale tests were carried out in Phase 2 to collect data for model verification. In Phase 3, over 150 parametric cases were analyzed using finite element models to develop assessment criteria for maximum moment and compressive strain limit. Each criterion includes a set of partial safety factors that were calibrated to meet target reliabilities selected based on recent research related to pipeline code development. The proposed criteria were applied to in-service pipeline examples with general corrosion features to estimate the remaining load-carrying capacity and to assess the conservatism of current practice.

Continuum Finite Element Methods to Establish Compressive Strain Limits for Offshore Pipelines in Ice Gouge Environments

2007 ◽  
Author(s):  
Ali Fatemi ◽  
Shawn Kenny ◽  
Farid Taheri
Keyword(s):  
Finite Element ◽  
Finite Element Methods ◽  
Compressive Strain ◽  
Pipeline System ◽  
Operational Parameters ◽  
Offshore Pipelines ◽  
Geometric Imperfection ◽  
Mesh Density ◽  
Post Buckling ◽  
Element Type

In the design process for offshore pipelines in ice gouge environments, compressive strain limits provide a basis to assess pipeline mechanical integrity for design load events. A parametric study, using the continuum finite element methods, has been conducted to assess the global pipeline moment-curvature response for displacement-based loading conditions through the post-buckling regime. The purpose of this study was to investigate the accuracy and efficiency of some computational parameters in simulating the stability characteristics of thick pipes. For that, the study used a pipe that has been the subject of a comprehensive and extensive experimental investigation. In specific, the study selected the exact geometric, material, loadings, boundary conditions and operational parameters similar to the BPXA Northstar pipeline system. The numerical analysis examined the effect of element type, mesh density, internal pressure, axial load, end moment, and geometric imperfection mode on the predicted post-buckling response. The analysis demonstrated the importance of element type, mesh density and characteristics of initial geometric imperfections on the post-buckling response of a thick-walled pipeline subject to combine loads. In addition, element performance and solution efficiency was examined.

Efficient Prediction of Contact Behavior in a 6-High Rolling Mill With Continuously Variable Crown Intermediate Rolls

2017 ◽  
Author(s):  
Feng Zhang ◽  
Arif S. Malik
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Mixed Finite Element ◽  
Mixed Finite Element Method ◽  
High Strength ◽  
Computational Time ◽  
Ferrous Alloys ◽  
Thickness Profile ◽  
Wide Range ◽  
Contact Force Distribution

Continuously Variable Crown (CVC) shifting mechanisms represent a control technology with wide range of capability to influence the thickness profile and flatness (shape) of metal strip and sheet in rolling-type manufacturing processes. Further, because of the efficiency and extensive control capability to operate on thin-gauge, high-strength ferrous alloys, the 6-high mill with CVC profiles machined onto the intermediate rolls (IR) represents a popular mill configuration. This is because of the large control range for the strip thickness profile and flatness, which results from lateral shifting of the CVC intermediate rolls. However, together with this efficiency and capability comes very complex contact behaviors between the rolls and strip, including highly non-linear contact force distribution, loss of contact, asymmetric roll wear, unwanted strip wedge profiles, and the need to apply corrective roll tilting. Therefore, for most effective industry use of 6-high mills with intermediate roll CVC shifting, a rapid and accurate mathematical rolling model is needed to predict and account for these complex contact behaviors. This paper introduces an efficient roll-stack computational model capable of simulating such rolling mills under steady-state conditions. The model formulation applies the simplified mixed finite element method (SM-FEM), which is adapted to simulate asymmetric 6-high CVC mill contact behaviors. Results for a specific case study compare favorably to those obtained from a large-scale commercial finite element simulation, yet require a small fraction of the associated computational time and effort.

The Initial Post-buckling Behavior of Face-Sheet Delaminations in Sandwich Composites

2003 ◽  
Vol 70 (2) ◽  
pp. 191-199 ◽  
Author(s):  
G. A. Kardomateas ◽  
H. Huang
Keyword(s):  
Interface Crack ◽  
Transverse Shear ◽  
Compressive Strain ◽  
Sandwich Beam ◽  
Local Buckling ◽  
Face Sheet ◽  
Material System ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Composite Face

Should an interface crack between the layers of the composite face-sheet or between the core and the composite face-sheet of a sandwich beam/plate exists, local buckling and possible subsequent growth of this interface crack (delamination) may occur under compression. In this study, the buckling, and initial post-buckling behavior is studied through a perturbation procedure that is based on the nonlinear beam equations with transverse shear included. Closed-form solutions for the load and midpoint delamination deflection versus applied compressive strain during the initial postbuckling phase are derived. Illustrative results are presented for several sandwich construction configurations, in particular with regard to the effect of material system and transverse shear.

Parameters Affecting the Local Buckling Response of High Strength Linepipe

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Ali Fatemi ◽  
Shawn Kenny
Keyword(s):  
Yield Strength ◽  
Large Scale ◽  
Mechanical Response ◽  
Local Buckling ◽  
High Strength ◽  
Combined Loading ◽  
Parameter Study ◽  
Model Parameters ◽  
Pipe Length ◽  
Numerical Predictions

The local buckling response and post-buckling mechanical performance of high strength linepipe subject to combined loading state was evaluated using the finite element (FE) simulator abaqus/standard v6.12. The constitutive model parameters were established through laboratory tests and the numerical modeling procedures were verified with large-scale experiments investigating the local buckling response of high strength linepipe. The numerical predictions demonstrated a high level of consistency and correspondence with the measured experimental behavior with respect to the peak moment, strain capacity, deformation mechanism, and local buckling response well into the postyield range. A parametric study on the local buckling response of high strength plain and girth weld pipelines was conducted. The loading conditions included internal pressure and end rotation. The pipe mechanical response parameters examined included moment–curvature, ovalization, local strain, and modal response. The magnitude and distribution of the characteristic geometric imperfections and the end constraint, associated with the boundary conditions and pipe length, had a significant influence on the predicted local buckling response. The importance of material parameters on the local buckling response, including the yield strength (YS), yield strength to tensile strength ratio (Y/T), and anisotropy, was also established through the numerical parameter study. For girth weld linepipe, the study demonstrated the importance of the local high/low misalignment, associated with the circumferential girth weld, on the local buckling response.

Buckling of High-Strength Steel Cylinders Under Cyclic Bending in the Inelastic Range1

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
George E. Varelis ◽  
Spyros A. Karamanos
Keyword(s):  
Finite Element ◽  
High Strength Steel ◽  
Numerical Study ◽  
Local Buckling ◽  
High Strength ◽  
Element Model ◽  
Cyclic Plasticity ◽  
Repeated Loading ◽  
Cross Sectional ◽  
Cyclic Bending

The present paper examines the structural behavior of elongated steel hollow cylinders, referred to as tubes or pipes, subjected to large cyclic bending, through a rigorous finite element simulation. The bent cylinders exhibit cross-sectional distortion, in the form of ovalization, combined with excessive plastic deformations. Those deformations grow under repeated loading and may lead to structural instability in the form of local buckling (wrinkling) and, eventually, failure of the loaded member. The study focuses on relatively thick-walled seamless cylindrical members made of high-strength steel, which exhibit local buckling in the plastic range of the steel material. The analysis is conducted using advanced nonlinear finite element models capable of describing both geometrical and material nonlinearities. A cyclic plasticity model that adopts the “bounding surface” concept is employed. The material model is calibrated through special-purpose material testing, and implemented within ABAQUS, using a user-subroutine. The finite element model is validated by comparison with two experiments on high-strength steel tubular members. Special emphasis is given on the increase of ovalization and the gradual development of small-amplitude initial wrinkles with repeated loading cycles. A parametric numerical study is conducted, aimed at determining the effects of initial wrinkles on plastic buckling performance.

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