Structural Design Capacity of X120 Linepipe

2004 ◽  
Author(s):  
Karel Minnaar ◽  
Brian W. Duffy ◽  
Erlend Olso ◽  
Scott D. Papka ◽  
Michael M. Zhang
Keyword(s):  
Structural Design ◽  
Large Scale ◽  
High Strength ◽  
External Pressure ◽  
Experimental Program ◽  
Element Analysis ◽  
Parametric Studies ◽  
Sensitivity Studies ◽  
Bending Loads ◽  
Grade Material

A new high strength steel linepipe with a specified minimum yield strength of 120 ksi (X120) has recently been introduced to industry. The newly developed linepipe meets all mechanical property targets of an X120 grade material as verified through an extensive small and large-scale experimental program. Design equations have been developed and verified with full scale testing that allow pipeline designs that take full economic advantage of the higher strength of X120. This paper focuses on the development and verification of capacity equations for bending loads, external pressure (collapse) loads, combined bending and external pressure loads, and internal pressure (burst) loads. The corresponding response of the pipe was investigated with finite element analysis (FEA). Analytical equations that predict the burst, bending, and collapse capacities were then established based on parametric studies performed using FEA models. To gain confidence in the models, full size pipe tests were conducted and the results compared to FEA. The testing demonstrated that the FEA models accurately predict the behavior of the X120 pipe. Modifications to the existing equations were made when necessary to ensure the capacity equations correctly capture the pipe response for higher D/t ratios and for the higher strength X120 material. Material sensitivity studies show that the new equations accurately predict the X120 behavior over the range of load conditions evaluated.

scholarly journals Failure Analysis on a Collapsed Flat Cover of an Adjustable Ballast Tank Used in Deep-Sea Submersibles

2019 ◽  
Vol 9 (23) ◽  
pp. 5258
Author(s):  
Fang Wang ◽  
Mian Wu ◽  
Genqi Tian ◽  
Zhe Jiang ◽  
Shun Zhang ◽  
...  
Keyword(s):  
Deep Sea ◽  
Material Selection ◽  
High Strength ◽  
External Pressure ◽  
Element Analysis ◽  
Ballast Tank ◽  
Material Inhomogeneity ◽  
Comprehensive Properties ◽  
Ultimate Cause ◽  
Flat Cover

A flat cover of an adjustable ballast tank made of high-strength maraging steel used in deep-sea submersibles collapsed during the loading process of external pressure in the high-pressure chamber. The pressure was high, which was the trigger of the collapse, but still considerably below the design limit of the adjustable ballast tank. The failure may have been caused by material properties that may be defective, the possible stress concentration resulting from design/processing, or inappropriate installation method. The present paper focuses on the visual inspections of the material inhomogeneity, ultimate cause of the collapse of the flat cover in pressure testing, and finite element analysis. Special attention is paid to the toughness characteristics of the material. The present study demonstrates the importance of material selection for engineering components based on the comprehensive properties of the materials.

Multiscale Modeling of a Notched Coupon Test for Triaxially Braided Composites

2019 ◽  
Vol 795 ◽  
pp. 172-179
Author(s):  
Yan Qi Hu ◽  
Wieslaw K. Binienda
Keyword(s):  
Multiscale Modeling ◽  
Large Scale ◽  
Laminated Composite ◽  
High Strength ◽  
Multiscale Model ◽  
Tensile Tests ◽  
Local Deformation ◽  
Modeling Method ◽  
Braided Composites ◽  
Element Analysis

Braided composites have been widely used in aerospace and automotive structures due to their light weight and high strength. Unlike metal or laminated composite material, the complex braided structure brings a lot of challenges when conducting numerical simulation. In this paper, a finite element analysis based meso-mechanical modeling for the two dimensional triaxially braided composite was developed. This mesoscale modeling method is capable of considering the detailed braiding geometry and architecture as well as the mechanical behavior of fiber tows, matrix and the fiber tow interface. Furthermore, a multiscale model combined both macroscale and mesoscale approaches and it is realized within LS-DYNA environment through Interface_components and Interface_linking. This combined multiscale modeling approach enables the full advantage of both the macroscale and mesoscale approaches, which can describe the details of local deformation and the global overall response features of the entire structure with the minimum computational expense. The evaluation and verification of the mesoscale approach and combined multiscale modeling method is through a notched coupon tensile tests conducted by Kohlman in both axial and transverse direction. The multiscale modeling method captures the response feature accurately so it has the ability to analyze large scale structures.

Rack and Pinion Lifting Device Structural Design of Large-Scale Dynamic Sculpture

2009 ◽  
Vol 628-629 ◽  
pp. 299-304
Author(s):  
C.Y. Lv ◽  
W.W. Shi ◽  
Xian Hai Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Design ◽  
Large Scale ◽  
Analysis Software ◽  
Element Analysis ◽  
The Finite Element Analysis

The design of lifting device for a large-scale dynamic sculpture at tourist district was introduced. According to its own characteristics of lift device, the "back-to-back" style of rack and pinion for the lift system was designed. It was used the finite element analysis software to analyze the strength of the rack and pinion which is a key part of the lift device. According to the stress of dedendum for the pinion is too bad, it was proposed that increased the radius of the fillet for dedendum.

Examination on Flaw Interactions in a Plate Subjected to Tensile and Bending Loads

2021 ◽  
Author(s):  
Yeong Cheol Im ◽  
Myung Hyun Kim
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Multiple Cracks ◽  
Element Analysis ◽  
Metallic Structures ◽  
Parametric Studies ◽  
Bending Loads ◽  
Conservative Estimation ◽  
Embedded Crack

Abstract Engineering Critical Assessment (ECA) procedure, which is a method to evaluate the integrity of various structures with embedded crack, surface crack and multiple cracks and so on. In BS7910, the acceptability of flaws in metallic structures is typically dealt with in terms of stress intensity factor solution. For the case with more than two flaws, BS7910 provides various flaw interaction rules. While such flaw interaction rules are developed based on many parametric studies, it is generally known to lead to very conservative results. In this study, the stress intensity factor solutions in a plate with multiple cracks are evaluated. Target structure is a simple plate subjected to tensile and bending loads, and a series of finite element analysis is carried out using ABAQUS. In addition, the results are validated against previous studies available in literatures. Based on the study, the distance criteria for multiple cracks in PD6493 and BS 7910 are found to be overly conservative. Therefore, a parametric investigation regarding the distance between multiple cracks is examined to reduce the overly conservative estimation in existing standards.

Experimental Measurement and Finite Element Analysis of Screw Spike Fatigue Loads

2007 ◽  
Author(s):  
Matthew G. Dick ◽  
David S. McConnell ◽  
Hans C. Iwand
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Failure ◽  
High Strength Steels ◽  
High Strength ◽  
Element Model ◽  
Element Analysis ◽  
Bending Fatigue ◽  
Fea Model ◽  
Bending Loads

Screw spikes, also known as coach screws, are an advanced alternative to common cut spikes for track fastening. Despite their ability to secure tie plates with a clamp load and utilization of high strength steels, they are still susceptible to bending fatigue failure from lateral wheel loads. A novel method of measuring these bending loads on screw spikes was developed and implemented to characterize the load environment of the screw spikes. Results indicated that measured peak bending loads under lateral wheel loads reached as high as 10,000 lbs for individual spikes, while others carried no load whatsoever. A finite element model was developed to determine the tensile stress fields created by the measured bending loads. A good correlation was found between the FEA model predicted point of highest stress and the location of fracture. Through the testing and analysis it was determined that lateral wheel loads are not distributed evenly among the four screw spikes of a single tie plate. Instead, it was found that one spike carried nearly no load while the spike opposite of it carried more load. Using the finite element analysis it was determined that the spike exposed to the higher loading was subjected to tensile stresses above its endurance limit, which would eventually lead to a bending fatigue failure.

Cleavage Fracture of Ultra-High-Strength Steels. Microscopic Observations. Numerical Analysis. Local Fracture Criterion

2014 ◽  
Vol 598 ◽  
pp. 168-177 ◽  
Author(s):  
Andrzej Neimitz ◽  
Ihor Dzioba ◽  
Urszula Janus
Keyword(s):  
Material Property ◽  
Cleavage Fracture ◽  
High Strength Steels ◽  
High Strength ◽  
Critical Value ◽  
Experimental Program ◽  
Fracture Mechanisms ◽  
Specimen Thickness ◽  
Element Analysis ◽  
Ultra High Strength Steels

In the paper the fracture mechanisms in ultra-high-strength steel are examined. However, the emphasis is on cleavage fracture, which was observed in the whole temperature range tested. The extent of cleavage depends on the specimen thickness and temperature. The experimental program consisted of tensile and fracture tests and was followed by scanning microscope observations of the fracture surfaces. Then, a full 3D elastic-plastic finite element analysis was carried out assuming finite strains. The numerical results support the postulate that the onset of cleavage jump is observed when the maximum opening stresses become higher than the critical value (the material property at a given temperature) over a distance greater than the critical value (material property independent of temperature). A discussion of so-called 3D stress parameters is presented.

Inelastic Shell Instability of Geometrically Imperfect Aluminum Alloy Circular Cylinders under Uniform External Pressure

2008 ◽  
Vol 45 (03) ◽  
pp. 175-181
Author(s):  
Carl T. F. Ross ◽  
Andrew P. F. Little ◽  
Graham Brown ◽  
Aravinthan Nagappan
Keyword(s):  
Aluminum Alloy ◽  
Hydrostatic Pressure ◽  
Analytical Solution ◽  
Structural Design ◽  
External Pressure ◽  
Circular Cylinders ◽  
External Hydrostatic Pressure ◽  
Element Analysis ◽  
Uniform External Pressure ◽  
Design Chart

The paper presents new experimental results on the collapse of unstiffened aluminum alloy circular cylinders suffering elastic and plastic nonsymmetric bifurcation buckling under external hydrostatic pressure. These results complement the results given in two previous Marine Technology papers written by the senior author, which were intended for the structural design of near-perfect unstiffened and ring-stiffened circular conical shells under external hydrostatic pressure. The present paper presents a structural design chart for geometrically imperfect circular cylinders under uniform external pressure, which is more likely to be used than the design charts for the previous near-perfect vessels because it represents the more "usual" case. In addition to an experimental analysis, theoretical analyses were also carried out. An analytical solution by von Mises was used, together with a finite element analysis solution, using the Shell 93 element of the ANSYS computer package. Comparison between ANSYS and the analytical solution was reasonable. A design chart is provided, which looks like it could be quite useful for practical purposes.

Development of Fatigue Resistant Heavy Wall Riser Connectors for Deepwater HPHT Dry Tree Riser Systems

2009 ◽  
Author(s):  
Ce´line Sches ◽  
Roy Shilling ◽  
Steve Shademan ◽  
Jacky Massaglia ◽  
Mike Payne ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
Base Material ◽  
High Strength Steels ◽  
High Strength ◽  
Cost Effective ◽  
Development Projects ◽  
Element Analysis ◽  
Comprehensive Development ◽  
Parametric Studies ◽  
Technical Solutions

BP is currently looking at the next generation of dry tree development projects in the US Gulf of Mexico (GOM) deepwater operating region. Some HPHT wells call for the design of 15 ksi or greater riser systems with sour service requirements. Over the last 10 years, NACE compliant high strength steels (HSS) together with fatigue resistant threaded and coupled connectors have proved to be reliable technical solutions top tensioned riser (TTR). Today their light weight and increased performance capabilities enable cost effective dry tree systems for water depths up to 10,000 feet. In the frame of BP xHPHT development projects, the design and qualification of Heavy Wall Threaded and Coupled (T&C) riser connectors for TTR applications was launched. Comprehensive development programs were built, involving numerous design variations, Finite Element Analysis evaluation and optimization — including parametric studies —, followed by intensive full scale static and fatigue testing campaigns. Those developments benefited from the design and field running experience accumulated with previous TTR projects, where innovative fatigue enhancement techniques and premium fatigue compliant sealing devices were engineered. In addition, combined static, dynamic and corrosion testing of base material is being conducted to assess and qualify the fatigue resistance of HSS up to 140 ksi under those conditions. This paper will present results and conclusions from these developments and will report the performance levels reached by Heavy Wall High Pressure T&C riser connectors and the associated high strength base material. Forward work plans on riser connectors for xHPHT, SCR and flowlines will also be discussed.

Tsunami loading of near-shoreline structures: a primer

2009 ◽  
Vol 36 (11) ◽  
pp. 1804-1815 ◽  
Author(s):  
Dan Palermo ◽  
Ioan Nistor ◽  
Younes Nouri ◽  
Andrew Cornett
Keyword(s):  
Structural Design ◽  
Large Scale ◽  
Solomon Islands ◽  
Building Codes ◽  
Experimental Program ◽  
Test Results ◽  
Significant Interest ◽  
Design Documents ◽  
Force Components ◽  
Site Planning

The effects and estimation of tsunami-induced loading on near-shoreline structures located within inundation zones have recently gained significant interest from researchers, engineers, and government agencies. Building codes, namely the 2005 National building code of Canada, do not explicitly consider tsunami loading, as it is understood that inland structures can be protected by proper site planning. However, recent catastrophic events (Indian Ocean, 2004; Solomon Islands, 2007) indicate that tsunami loading should be considered in structural design. Presented herein is a review of force components that arise from tsunami-induced hydraulic bores running inland, along with proposed loading combinations and load cases readily applicable for building codes. Test results from a comprehensive experimental program conducted in a large-scale flume are also provided. A comparison of experimental results with force components provided in readily available design documents is presented, and suggestions for improvements are further discussed.

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