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.

A Micromechanics Approach to Assess Ductile Crack Initiation in Damaged Pipelines

2003 ◽  
Author(s):  
Claudio Ruggieri ◽  
Fernando F. Santos ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Ductile Fracture ◽  
Large Scale ◽  
Cell Model ◽  
High Strength ◽  
Void Coalescence ◽  
Model Parameters ◽  
Ductile Crack ◽  
Cracking Behavior ◽  
Damage Criterion ◽  
Limited Applicability

This study explores the capabilities of a computational cell framework into a 3-D setting to model ductile fracture behavior in tensile specimens and damaged pipelines. The cell methodology provides a convenient approach for ductile crack extension suitable for large scale numerical analyses which includes a damage criterion and a microstructural length scale over which damage occurs. Laboratory testing of a high strength structural steel provides the experimental stress-strain data for round bar and circumferentially notched tensile specimens to calibrate the cell model parameters for the material. The present work applies the cell methodology using two damage criterion to describe ductile fracture in tensile specimens: (1) the Gurson-Tvergaard (GT) constitutive model for the softening of material and (2) the stress-modified, critical strain (SMCS) criterion for void coalescence. These damage criteria are then applied to predict ductile cracking for a pipe specimen tested under cycling bend loading. While the methodology still appears to have limited applicability to predict ductile cracking behavior in pipe specimens, the cell model predictions of the ductile response for the tensile specimens show good agreemeent with experimental measurements.

Constitutive Modeling of Corneal Tissue: Influence of Three-Dimensional Collagen Fiber Microstructure

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Shuolun Wang ◽  
Hamed Hatami-Marbini
Keyword(s):  
Extracellular Matrix ◽  
Constitutive Modeling ◽  
Mechanical Response ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Vital Role ◽  
Collagen Fibrils ◽  
Model Parameters ◽  
Corneal Tissue ◽  
Numerical Predictions

Abstract The cornea, the transparent tissue in the front of the eye, along with the sclera, plays a vital role in protecting the inner structures of the eyeball. The precise shape and mechanical strength of this tissue are mostly determined by the unique microstructure of its extracellular matrix. A clear picture of the 3D arrangement of collagen fibrils within the corneal extracellular matrix has recently been obtained from the secondary harmonic generation images. However, this important information about the through-thickness distribution of collagen fibrils was seldom taken into account in the constitutive modeling of the corneal behavior. This work creates a generalized structure tensor (GST) model to investigate the mechanical influence of collagen fibril through-thickness distribution. It then uses numerical simulations of the corneal mechanical response in inflation experiments to assess the efficacy of the proposed model. A parametric study is also done to investigate the influence of model parameters on numerical predictions. Finally, a brief comparison between the performance of this new constitutive model and a recent angular integration (AI) model from the literature is given.

Parameter Study of Numerical Simulation for Tensile Properties of Multi-Layer SMATed Alloys

2015 ◽  
Vol 813 ◽  
pp. 293-299
Author(s):  
Yun Wan ◽  
Xiao Qiang Wang ◽  
Ji Feng Zhang ◽  
Jian Lu ◽  
Li Min Zhou
Keyword(s):  
High Strength ◽  
Tangential Direction ◽  
Advanced Materials ◽  
Surface Mechanical Attrition Treatment ◽  
Parameter Study ◽  
Model Parameters ◽  
Tensile Performance ◽  
Simulation And Experiment ◽  
Marine Engineering ◽  
Simulation Parameters

Strength and ductility are very important to marine engineering. Because of their remarkable mechanical properties, nanocrystalline metals have been the focus of much research in recent years. Based on surface mechanical attrition treatment (SMAT) and warm co-rolling technologies, the resulting material performances amazingly exhibit high strength and exceptional ductility. Therefore, this method is a promising avenue for advanced materials for marine engineering. Cohesive finite element method (CFEM) is employed to investigate the tensile performance of multi-layer SMATed alloys. With the results of simulation and experiment compared, simulation parameters have been studied . According to comparing different simulation results, the model parameters, normal direction strength and tangential direction strength in CFEM are studied.

Influence of Geotechnical Loads on Local Buckling Behavior of Buried Pipelines

2008 ◽  
Author(s):  
Hiva Mahdavi ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Local Buckling ◽  
Small Diameter ◽  
Ground Movement ◽  
Combined Loading ◽  
Fe Model ◽  
Buried Pipelines ◽  
Limit States

Buried pipelines can be subjected to differential ground movement events. The ground displacement field imposes geotechnical loads on the buried pipeline and may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. The conventional engineering approach to define the mechanical performance of pipelines has been based on combined loading events for “in-air” conditions. This methodology is assumed to be overly conservative and ignores soil effects that imposes geotechnical loads and also provides restraint, on buried pipelines. The importance of pipeline/soil interaction and load transfer mechanisms that may affect local buckling of buried pipelines is not well understood. In this study a three-dimensional continuum finite element (FE) model, using the software package ABAQUS/Standard, was developed and calibrated based on large-scale tests on the local buckling of linepipe segments for in-air and buried conditions. The effects of geotechnical boundary conditions on pipeline deformation mechanism and load carrying capacity were examined for a single small diameter pipeline with average diameter to thickness ratio and deep buried condition. The calibrated model successfully reproduced the large-scale buried test results in terms of the local buckling location, pipeline carrying load capacity, soil deformation and soil failure mechanism.

Experimental and Numerical Evaluation of SnAgCu and SnPb Solders Using a MicroBGA Under Accelerated Temperature Cycling Conditions

2004 ◽  
Author(s):  
Bryan Rodgers ◽  
Jeff Punch ◽  
Claire Ryan ◽  
Finbarr Waldron ◽  
Liam Floyd
Keyword(s):  
Fatigue Life ◽  
Large Scale ◽  
Temperature Cycling ◽  
Lead Free ◽  
Model Parameters ◽  
Lead Free Solder ◽  
Element Analysis ◽  
Snagcu Solder ◽  
Numerical Predictions ◽  
Free Solder

A comparative evaluation of the leading lead-free solder candidate (95.5Sn3.8Ag0.7Cu) and traditional tin-lead solder (63Sn37Pb) under thermal cycling conditions was carried out. A test vehicle consisting of four daisy chained 10×10 array 0.8mm pitch plastic micro ball grid arrays (microBGA) mounted on an 8-layer FR4 printed wiring board was designed. The board finish was organic solder preservative (OSP) for the lead-free devices and hot air solder levelled (HASL) in the case of the eutectic devices. An event detector was used to monitor the continuity of each daisy chain during accelerated temperature cycling, where the test vehicles were cycled with a ramp rate of approximately 3°C per minute from −40°C to 125°C, with 10-minute dwells and a total cycle time of 2 hours 10 minutes. Results to date plotted using a Weibull distribution indicate that the SnAgCu solder is more reliable under these conditions. Experiments were also carried out on large-scale lead-free solder specimens to determine the parameters required for the Anand viscoplasticity model. The Anand model was then implemented in finite element analysis using ANSYS®, where the submodelling technique was employed to determine the viscoplastic work per thermal cycle for each solder joint along the package diagonal. Schubert’s fatigue life model was used to predict the number of cycles to failure of each joint, although it should be noted that the necessary model parameters for the may need to be calibrated. Results indicate that the joint under the die edge is likely to fail first and that the SnAgCu solder is more fatigue resistant. The numerical predictions underestimate the fatigue life in both cases.

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.

Thermo-Mechanical Damage Modeling for a Glass-Fiber Phenolic-Resin Composite Material

2005 ◽  
Author(s):  
Changsong Luo ◽  
Paul E. DesJardin
Keyword(s):  
Experimental Data ◽  
Large Scale ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Resin Composite ◽  
Mechanical Damage ◽  
Composite Fiber ◽  
Darcy Law ◽  
Stress Concentrations ◽  
Numerical Predictions

The objective of this research is the development of a thermo-mechanical damage model for composite materials subject to high temperature thermal and radiative environments that are representative of large scale fires. The damage to the structure is expressed as two regions of non-charred and charred material. In the char region, the pyrolysis process of resin is complete and there are only fiber, char and gas. Homogenization methods are imposed to treat the damaged material in terms of the volume fractions associated with composite fiber, resin and char. A transport equation for the phase averaged temperature is presented using a Darcy law to account for the gas transport in the structure. Mechanical response in the composite is taken into account by solving a homogenized form of the linear elasticity equations. Required transport properties for temperature and displacement equations are based on mixture weighted properties of the fiber, gas, resin and char and are dependent on the local volume fraction of each. Numerical simulations of a two-dimensional composite clamped beam subject to radiation heat loading are presented. Overall, good agreement is obtained between the numerical predictions and experimental data for temperature and gas pressure with comparisons to the thermal experimental data of Henderson and Florio [8,9]. Results show that during early stages of heating, the decomposition of the resin results in local stress concentrations due to the increase in temperature and pressure.

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.

DOGAL LAD

Alloy Digest ◽  
2011 ◽  
Vol 60 (10) ◽  
Keyword(s):  
Yield Strength ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Minimum Yield

Abstract Dogal 300 LAD, 340 LAD, 380 LAD, 420 LAD, 460 LAD and 500 LAD are high-strength low alloyed steels intended for pressing. The designation in the name is the guaranteed minimum yield strength. Dogal steels can be zinc coated. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on surface qualities as well as forming, heat treating, joining, and surface treatment. Filing Code: CS-167. Producer or source: SSAB Swedish Steel Inc..

RUUKKI RAEX 300

Alloy Digest ◽  
2012 ◽  
Vol 61 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Shear Strength ◽  
Impact Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Structural Components ◽  
Wear Resistant

Abstract RUUKKI RAEX 300 (typical yield strength 900 MPa) is part of the Raex family of high-strength and wear-resistant steels with favorable hardness and impact toughness to extend life and decrease wear in structural components. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on wear resistance as well as forming, machining, and joining. Filing Code: SA-643. Producer or source: Rautaruukki Corporation.

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