Reeling Analysis and Limit State Criteria

2016 ◽  
Author(s):  
Jianfeng Xu ◽  
Srinivas Vishnubhotla ◽  
Olav Aamlid ◽  
Leif Collberg
Keyword(s):  
Finite Element ◽  
Limit State ◽  
Local Buckling ◽  
Limit States ◽  
Fast Speed ◽  
Fatigue And Fracture ◽  
Different Types ◽  
Steel Catenary Risers ◽  
Fracture Performance ◽  
Limit State Criteria

Reeling has been an attractive offshore installation method for rigid flowlines and steel catenary risers due to its fast speed, cost effectiveness and reliability. Over years of evolution, it has become a proven technology, and the understanding to the engineering fundamentals is greatly improved as well. Due to the reeling process, the pipeline is plastically deformed; residual stresses, pipe ovality, and pipe out of straightness are increased. The strength, fatigue, and fracture performance of the pipe and the girth weld have to be closely evaluated to insure the pipeline integrity during and after the installation. As part of the installation design, different types of analyses are generally carried out to demonstrate the reelability, and the pipeline responses against all limit states. However, the methods adopted by different contractors can vary greatly. In this paper, the engineering fundamentals of reeling process are reviewed. A few typical reeling analyses, both analytical and finite element based, are demonstrated with examples. The local buckling limit state criteria based on DNV-OS-F101 for different stages of reeling are also illustrated.

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.

FEA of a Laminate Internal Buckle Arrestor for Deep Water Pipe-in-Pipe Flowlines

2009 ◽  
Author(s):  
Haoyu Wang ◽  
Jason Sun ◽  
Paul Jukes
Keyword(s):  
Deep Water ◽  
Mechanical Design ◽  
Limit State ◽  
Local Buckling ◽  
Design Parameters ◽  
Limit States ◽  
Element Analysis ◽  
Operational Lifetime ◽  
Buckle Propagation ◽  
Buckle Arrestors

Development of deepwater oil reservoirs has been undertaken in the Gulf of Mexico (GoM) where flowlines are installed in water depths in the vicinity of 2,740m (9,000ft). Preventing the propagation of local collapse/buckle failures is one of the key engineering design limit states that is defined in the industry codes to ensure the pipeline integrity. Deep-water buckle propagation is almost unavoidable as the wall thickness selection cannot be directly driven by the buckle propagation limit state. Field data indicates that once a buckle happens, the flowline could collapse for many kilometers instantly. Buckle propagation could cause substantial economic impact if left uncontrolled. For Pipe-in-Pipe (PIP) flowline, due to lack of pressure differential, the jacket pipe is a fragile component in terms of buckle propagation. It is crucial to prevent any possible local buckling during the flowline installation and during the entire operational lifetime. One way to stop buckle propagation is to utilize buckle arrestors of various types. Successfully designed buckle arrestors can contain such disasters to a limited pipeline section. Internal buckle arrestors are a relatively new solution for PIP systems being investigated by the industry. As it is installed in the annulus of PIP, it becomes a preferred choice since it fits all types of installation methods. The objective of this paper is to present the design and finite element analysis (FEA) of a laminate type internal buckle arrestor, and to investigate the effectiveness of this innovative buckle arrestor design for deepwater flowline. Sensitivities of key design parameters are explored with the purpose of guiding detailed mechanical design.

Limit state behavior and response sensitivity analysis of endplate steel connections with shape memory alloy bolts

2020 ◽  
Vol 31 (18) ◽  
pp. 2071-2087
Author(s):  
Majid Mohammadi Nia ◽  
Saber Moradi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Numerical Study ◽  
Slenderness Ratio ◽  
Limit State ◽  
Local Buckling ◽  
Limit States ◽  
Response Sensitivity ◽  
Cyclic Response ◽  
Steel Connections

Shape memory alloys have been used in developing self-centering steel moment connections. This article presents a numerical study aiming at evaluating the cyclic response sensitivity and limit states of extended endplate steel connections with shape memory alloy bolts. Three-dimensional finite element models are developed and validated against a recent experimental study. Using a statistical design-of-experiment method, the effects of 21 design factors and their interactions on the cyclic response of shape memory alloy connections are assessed. The sensitivity of six response parameters is studied. In addition, four limit states for shape memory alloy connections are discussed, including beam local buckling, bolt excessive axial strain, endplate yielding, and column flange yielding. Results show that endplate thickness, shape memory alloy bolt diameter, beam web slenderness ratio, and shape memory alloy maximum transformation strain are the most influential factors. Furthermore, endplate yielding is found to be the governing limit state in almost 80% of the analyzed connections, whereas shape memory alloy bolt excessive strain and column flange yielding are observed in less than 20% and 5% of the connections, respectively. Beam local buckling is not governing in the analyzed shape memory alloy connections designed as per the AISC 358-16 and AISC 341-16 seismic design requirements for extended endplate connections and highly ductile members.

scholarly journals A comparative study on the performance of different types of wallslab connections in liquid containing concrete structures

2021 ◽  
Author(s):  
Nima Atashi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Study ◽  
Limit State ◽  
Concrete Structures ◽  
Element Analysis ◽  
Common Solution ◽  
Construction Joint ◽  
Linear Finite Element ◽  
Different Types

Waterstops are commonly used at cold joints in construction of liquid containing concrete structures. A common issue with application of waterstops, is their conflict with top layer of slab reinforcements. A common solution is to form an upturn part that raises the waterstop clear of the top slab bars. However, effects of these different types of construction joints on the performance of structures have not been investigated. To that end, full-scale wall-slab specimens, each representing a different type of construction joint, are built and tested under different monotonic and cyclic loadings. The performance of these specimens is compared with regards to first cracking, limit state capacity and leakage. Results of the tests show that conventional flat joint, behaves more rigidly compared to other types of joints. A non-linear finite element analysis of a typical wall-slab specimen, is also presented and its results are compared with the results of the experiments.

scholarly journals A comparative study on the performance of different types of wallslab connections in liquid containing concrete structures

2021 ◽  
Author(s):  
Nima Atashi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Study ◽  
Limit State ◽  
Concrete Structures ◽  
Element Analysis ◽  
Common Solution ◽  
Construction Joint ◽  
Linear Finite Element ◽  
Different Types

Waterstops are commonly used at cold joints in construction of liquid containing concrete structures. A common issue with application of waterstops, is their conflict with top layer of slab reinforcements. A common solution is to form an upturn part that raises the waterstop clear of the top slab bars. However, effects of these different types of construction joints on the performance of structures have not been investigated. To that end, full-scale wall-slab specimens, each representing a different type of construction joint, are built and tested under different monotonic and cyclic loadings. The performance of these specimens is compared with regards to first cracking, limit state capacity and leakage. Results of the tests show that conventional flat joint, behaves more rigidly compared to other types of joints. A non-linear finite element analysis of a typical wall-slab specimen, is also presented and its results are compared with the results of the experiments.

Collision-Accidental Limit States Performance of Double-Hull Oil Tanker Structures: Pre-CSR versus CSR Designs

2009 ◽  
Vol 46 (04) ◽  
pp. 183-191
Author(s):  
Jeom kee Paik ◽  
Jae Hyung Park ◽  
Emmanuel Samuelides
Keyword(s):  
Finite Element ◽  
Structural Design ◽  
Limit State ◽  
Nonlinear Finite Element ◽  
Structural Performance ◽  
Limit States ◽  
Oil Tankers ◽  
Double Hull ◽  
The Impact ◽  
Oil Tanker

To mitigate the impact of consequences of ship collisions in terms of health, safety, and the environment, it has been made mandatory that hull structures of all oil tankers have double sides and double bottoms. In recent years, International Association of Classification Societies (IACS) has developed Common Structural Rules (CSR) for structural design of double-hull oil tankers on the basis of limit states, together with the traditional approach using the allowable working stress that has been a basis of pre-CSR. The application of CSR may result in some differences in terms of structural performance, among other aspects. The main objective of the present paper is to investigate the structural performance of CSRdesigned tankers associated with ship collisions. This aspect might be interesting, although CSR are not intended specifically to improve collision performance. As an illustrative example, an AFRAMAX-class double-hull oil tanker structure with same deadweight designed by both pre-CSR and CSR methods is studied by comparing their collision energy-absorption capabilities as obtained by nonlinear finite element methods. It is found that the collision performance of the CSR design could be improved by 5% to 25% compared with that of the pre-CSR design, depending on the accidental limit state criteria. However, it is concluded that the strength performance of the CSR vessel is similar to that of the pre-CSR vessel in terms of collision-accidental limit states, considering the uncertainties involved in conjunction with collision scenarios and nonlinear finite element method modeling techniques. Although the present study deals with some very specific scenarios of collisions, the insights and conclusions developed will still be useful for recognizing a structural design trend related to collision-accidental limit states

Limit Load Capacity of Thick-Walled Pipe Loaded by Internal Pressure and Bending

2021 ◽  
Author(s):  
Ruud Selker ◽  
Joost Brugmans ◽  
Ping Liu ◽  
Carlos Sicilia
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Load Capacity ◽  
Limit State ◽  
Local Buckling ◽  
Limit Load ◽  
Combined Loading ◽  
Fe Model ◽  
State Equations

Abstract Internally pressurised pipe behaves differently than externally pressurised pipe. DNVGL-ST-F101 [4], a prevailing standard for the design of submarine pipelines, provides limit-state equations for combined loading that are valid only if the diameter-to-wall-thickness ratio (D/t) is between 15 and 45. A recent study has shown that the results are increasingly conservative for lower values of this ratio if the nett pressure is acting on the pipe’s outside [8], especially if it is below 20. In this paper, the applicability of the limit-state equations for thick-walled pipe with D/t less than 15 and loaded by a nett internal pressure has been investigated. The first step was a fundamental review of the formulations. Next, the predicted capacities were compared with those estimated using a finite-element (FE) model. The results greatly coincided, which indicates that the conservatism underlying the formulations does not depend on D/t. Hence they can be used for design against local buckling under internal overpressure, too, when the ratio is below 15.

Titanium Riser Configurations

2002 ◽  
Author(s):  
Bernt J. Leira ◽  
Arve Bjo̸rset ◽  
Stig Berge
Keyword(s):  
Axial Force ◽  
Mechanical Design ◽  
Limit State ◽  
Local Buckling ◽  
Bending Moment ◽  
Relative Importance ◽  
Limit States ◽  
Characteristic Response ◽  
Riser Design ◽  
Critical Sections

The present paper addresses mechanical design aspects for titanium riser configurations. Three main types of riser systems are considered: • Vertical top-tensioned risers suspended from a TLP; • Catenary risers suspended from a TLP; • Pliant-wave risers suspended from a Semi-submersible. For each configuration, characteristic response properties related to bending moment and axial force diagrams are presented. Critical sections for each riser system are identified. For the vertical top-tensioned riser, design of a bending stiffener located at the seabed is briefly addressed. Capacity formulations and the relative importance of the following mechanical limit states are addressed: • Yielding; • Local buckling; • Fatigue. Differences between parameters influencing the various limit states for titanium respectively steel are highlighted. The local buckling limit state is subsequently focused upon in some more detail in relation to loads due to combined external overpressure and bending.

RELIABILITY ANALYSIS OF STEEL BRACED REINFORCED CONCRETE FRAMES WITH SEMI-RIGID CONNECTIONS

2012 ◽  
Vol 12 (05) ◽  
pp. 1250037 ◽  
Author(s):  
H. B. BASAGA ◽  
M. E. KARTAL ◽  
A. BAYRAKTAR
Keyword(s):  
Finite Element ◽  
Reliability Analysis ◽  
Compression Strength ◽  
Limit State ◽  
Braced Frames ◽  
Limit States ◽  
Strength Limit ◽  
Steel Strength ◽  
Reliability Method ◽  
Story Drift

This paper presents the reliability analysis of the frame structures with semi-rigid connections. For this purpose, the SEMIFEM finite element program that is capable of dealing with the semi-rigid connections is coded in FORTRAN. Then, this program is connected to the reliability algorithm. The direct coupling method, which is a combination of the reliability method and finite element method, is utilized to determine the reliability indexes and probabilities of failure for the structure. The first order reliability method (FORM) is the one favored in the present reliability analysis. Two sets of steel framed structures are analyzed; each of four and eight stories, consisting of a portal frame and three types of concentrically braced frames. Concrete compression strength limit state in reinforced concrete (RC) columns, steel strength limit state in steel braces and inter-story drift limit state are considered in reliability evaluation. According to the limit states, X braced frames are determined as the safest structures, while the portal frames are regarded as the most unsafe structures. As the connection percentage increases, the safety of the structure increases in terms of inter-story drift and steel strength limit states, but decreases for concrete compression strength limit states.

Buried Corrugated Thermoplastic Pipe: Simulation and Design

2003 ◽  
Vol 1849 (1) ◽  
pp. 135-143 ◽  
Author(s):  
B. W. Schafer ◽  
T. J. McGrath
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Design Method ◽  
Three Dimensional ◽  
Local Buckling ◽  
Element Model ◽  
Computational Method ◽  
Limit States ◽  
Strain Capacity ◽  
Negative Bending

The objective of this study was to demonstrate a computational method for assessing the allowable depth of fill over a buried thermoplastic profile wall (corrugated) plastic pipe and to compare the results with those of the recently adopted AASHTO design method. The computational method is demonstrated for a 1,500-mm (60-in.) diameter high-density polyethylene profile wall pipe but is applicable to all profile wall thermoplastic pipe that exhibits local buckling limit states. The computational model compares strain demands predicted from a two-dimensional plane strain finite element model of buried pipe in the embankment condition with strain capacity predicted from a three-dimensional finite element model of a pipe–soil segment undergoing thrust or positive and negative bending, or both. The strain demands indicate the dominance of thrust strains as opposed to bending strains in the overall behavior, particularly for intermediate to larger fill depths. In the examined profile the ultimate strain capacity is limited by local buckling for thrust strains and positive bending (crest in compression) and inward radial movement of the crest for negative bending (liner in compression). Predictions for depth of fill by the new AASHTO design method for thermoplastic pipe and the computational method agree within 10% of one another when uniform soil distribution is considered and within 20% of one another when a soft haunch and other soft soils are considered in the pipe–soil envelope.

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