Post-Yield Strain Tests of 20-in. Casing With Weld-on Connectors

1983 ◽  
Vol 105 (4) ◽  
pp. 554-559
Author(s):  
W. R. Blackstone ◽  
T. L. Blose ◽  
J. W. Galate
Keyword(s):  
Ultimate Strength ◽  
Test Data ◽  
Compression Test ◽  
Axial Strain ◽  
Full Scale ◽  
The State ◽  
Oil Well ◽  
Yield Strain ◽  
Tension And Compression ◽  
Permafrost Regions

Soils in permafrost regions may undergo significant subsidence due to thawing. Oil well surface casing embedded in such soils may be subjected to strains well beyond yield, whatever the casing properties might be. To deal with this, the State of Alaska has issued a specification defining the amount of axial strain that the casing, together with its connectors, must be able to withstand without parting. This paper presents full-scale tension and compression test data demonstrating that a particular weight and grade of 20-in. casing with premium weld-on connectors is a system exceeding those requirements. It is shown that, in tension, the material ultimate strength is reached first in the casing. Similarly, it is shown that, in compression, the casing buckles plastically before the connector fails.

scholarly journals Prediction of the Ultimate Strength of Notched and Unnotched IM7/977-3 Laminated Composites Using a Micromechanics Approach

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3491
Author(s):  
Manzar Masud ◽  
Moosa S. M. Al Kharusi ◽  
Muhammad Umair Ali ◽  
Aamir Mubashar ◽  
Shaik Javeed Hussain ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Test Data ◽  
Experimental Test ◽  
Laminated Composites ◽  
Compressive Load ◽  
Failure Criteria ◽  
Analysis Technique ◽  
Proposed Model ◽  
Tension And Compression ◽  
Failure Loads

This paper proposes a multi-scale analysis technique based on the micromechanics of failure (MMF) to predict and investigate the damage progression and ultimate strength at failure of laminated composites. A lamina’s representative volume element (RVE) is developed to predict and calculate constituent stresses. Damages that occurred in the constituents are calculated using separate failure criteria for both fiber and matrix. Subsequently, the volume-based damage homogenization technique is utilized to prevent the localization of damage throughout the total matrix zone. The proposed multiscale analysis procedure is then used to investigate the notched and unnotched behavior of three multi-directional composite layups, [30, 60, 90, −60, 30]2s, [0, 45, 90, −45]2s, and [60, 0, −60]3s, subjected to static tension and compression loading. The specimen is fabricated from unidirectionally reinforced composite (IM7/977-3). The prediction of ultimate strength at failure and equivalent stiffness are then benchmarked against the experimental test data. The comparative analysis with various failure models is also carried out to validate the proposed model. MMF demonstrated the capability to correctly predict the ultimate strength at failure for a range of multidirectional composites laminates under tensile and compressive load. The numerically predicted findings revealed a good agreement with the experimental test data. Out of the three investigated composite layups, the simulated results for the quasi-isotropic [0, 45, 90, −45]2S layup agreed extremely well with the experimental results with all the percentage errors within 10% of the measured failure loads.

Guidelines for CFD Simulations of Spar VIM

2013 ◽  
Author(s):  
Charles Lefevre ◽  
Yiannis Constantinides ◽  
Jang Whan Kim ◽  
Mike Henneke ◽  
Robert Gordon ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Test Data ◽  
Model Test ◽  
Model Tests ◽  
Full Scale ◽  
Mooring System ◽  
Time Step ◽  
Cfd Simulations ◽  
Scaled Model ◽  
Sway Motion

Vortex-Induced Motion (VIM), which occurs as a consequence of exposure to strong current such as Loop Current eddies in the Gulf of Mexico, is one of the critical factors in the design of the mooring and riser systems for deepwater offshore structures such as Spars and multi-column Deep Draft Floaters (DDFs). The VIM response can have a significant impact on the fatigue life of mooring and riser components. In particular, Steel Catenary Risers (SCRs) suspended from the floater can be sensitive to VIM-induced fatigue at their mudline touchdown points. Industry currently relies on scaled model testing to determine VIM for design. However, scaled model tests are limited in their ability to represent VIM for the full scale structure since they are generally not able to represent the full scale Reynolds number and also cannot fully represent waves effects, nonlinear mooring system behavior or sheared and unsteady currents. The use of Computational Fluid Dynamics (CFD) to simulate VIM can more realistically represent the full scale Reynolds number, waves effects, mooring system, and ocean currents than scaled physical model tests. This paper describes a set of VIM CFD simulations for a Spar hard tank with appurtenances and their comparison against a high quality scaled model test. The test data showed considerable sensitivity to heading angle relative to the incident flow as well as to reduced velocity. The simulated VIM-induced sway motion was compared against the model test data for different reduced velocities (Vm) and Spar headings. Agreement between CFD and model test VIM-induced sway motion was within 9% over the full range of Vm and headings. Use of the Improved Delayed Detached Eddy Simulation (IDDES, Shur et al 2008) turbulence model gives the best agreement with the model test measurements. Guidelines are provided for meshing and time step/solver setting selection.

Non-Linear Stress Analysis of Complex Umbilical Cross-Sections

2002 ◽  
Author(s):  
Svein Sævik ◽  
Knut I. Ekeberg
Keyword(s):  
Cross Section ◽  
Axial Force ◽  
Plastic Material ◽  
Axial Strain ◽  
Development Program ◽  
Full Scale ◽  
Small Scale ◽  
Applied Theory ◽  
Element Formulation ◽  
Material Models

Nexans Norway is, together with Marintek, currently developing a software for detailed analysis of complex umbilical cross-section designs. The software development project combines numerical methods with small-scale testing of involved materials, as well as full-scale testing of a wide variety of umbilical designs, essential for calibration and verification purposes. Each umbilical design is modelled and comparisons are made with respect to global behaviour in terms of: • Axial strain versus axial force; • Axial strain versus torsion; • Torsion versus torsion moment for various axial force levels; • Moment versus curvature for different tension levels. The applied theory is based on curved beam and curved axisymmetric thin shell theories. The problem is formulated in terms of finite elements applying the Principle of Virtual Displacements. Each body of the cross-section interacts with the other bodies by contact elements which are formulated by a penalty formulation. The contact elements operate in the local surface coordinate system and include eccentricity, surface stiffness and friction effects. The software is designed to include the following functionality: • Arbitrary geometry modelling including helical elements wound into arbitrary order; • The helical elements may include both tubes and filled bodies; • Elastic, hyper-elastic, and elastic-plastic material models; • Initial strain; • Contact elements, including friction; • Tension, torsion, internal pressure, external pressure, bending and external contact loading (caterpillars, tensioners, etc.). The paper focuses on the motivation behind the development program including a description of the different activities. The theory is described in terms of kinematics, material models and finite element formulation. A test example is further presented comparing predicted behaviour with respect to full-scale test results.

Analyses of Full-Scale Tank Car Shell Impact Tests

2007 ◽  
Author(s):  
Y. H. Tang ◽  
H. Yu ◽  
J. E. Gordon ◽  
M. Priante ◽  
D. Y. Jeong ◽  
...  
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Three Dimensional ◽  
Full Scale ◽  
Collision Dynamics ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Closed Form Solutions

This paper describes analyses of a railroad tank car impacted at its side by a ram car with a rigid punch. This generalized collision, referred to as a shell impact, is examined using nonlinear (i.e., elastic-plastic) finite element analysis (FEA) and three-dimensional (3-D) collision dynamics modeling. Moreover, the analysis results are compared to full-scale test data to validate the models. Commercial software packages are used to carry out the nonlinear FEA (ABAQUS and LS-DYNA) and the 3-D collision dynamics analysis (ADAMS). Model results from the two finite element codes are compared to verify the analysis methodology. Results from static, nonlinear FEA are compared to closed-form solutions based on rigid-plastic collapse for additional verification of the analysis. Results from dynamic, nonlinear FEA are compared to data obtained from full-scale tests to validate the analysis. The collision dynamics model is calibrated using test data. While the nonlinear FEA requires high computational times, the collision dynamics model calculates gross behavior of the colliding cars in times that are several orders of magnitude less than the FEA models.

Determination of the Wave Spectrum From Observed Motions of a Vehicle in a Seaway

1967 ◽  
Vol 11 (03) ◽  
pp. 199-208
Author(s):  
Wilbur Marks
Keyword(s):  
Wave Spectrum ◽  
Full Scale ◽  
The State ◽  
Vertical Acceleration ◽  
Time Histories

If, during full-scale trials, it is not possible to measure the state of the sea with a reliable wavemeter, then certain motion records may be combined to achieve the same end. The derivation of the wave spectrum from the time histories of pitch, heave (vertical acceleration), and bow immersion is presented. The problem of the conversion of acceleration to displacement is discussed. The method is applied to the particular case of the hydrofoil boat Sea Legs.

Ghana: Part 2

2020 ◽  
pp. 179-211
Author(s):  
Robert L. Tignor
Keyword(s):  
United Nations ◽  
Free Market ◽  
Addis Ababa ◽  
Full Scale ◽  
The State ◽  
Development Plan ◽  
Economic Policies ◽  
Mixed Economy ◽  
The United Nations ◽  
Economic Adviser

This chapter looks at how W. Arthur Lewis left Ghana as a member of the Ghanaian delegation to the all-African conference meeting in Addis Ababa, Ethiopia. He did not return. In Addis, he announced his intention to take up a new post at the United Nations. He did not, however, sever his ties with Ghana, and he was to return briefly in 1963 to offer advice on the Seven-Year Development Plan. Because he had not had time to train a replacement, his departure left the Ghanaians without a fulltime economic adviser. The responsibility for drafting the budget and overseeing the five-year plan devolved on a variety of outside consultants and Ghanaian ministers themselves. At first Ghana drifted in the direction of more state controls over the economy and greater suspicion of the free market; but by 1960 and 1961 the drift had become a full-scale push as the state began to replace the Lewis programs that had featured a mixed economy with ones that looked exclusively to the state. The early pressures to scrap the Lewis economic policies and move to the left came as much in response to problems that had haunted the Ghanaian economy throughout the late 1950s as to ideology, notably trade and budgetary deficits.

Full-Scale Measurements of Welding-Induced Initial Deflections and Residual Stresses in Steel-Stiffened Plate Structures

2018 ◽  
Vol Vol 160 (A4) ◽  
Author(s):  
M S Yi ◽  
C M Hyun ◽  
J K Paik
Keyword(s):  
Residual Stresses ◽  
Ultimate Strength ◽  
Computational Models ◽  
Plate Thickness ◽  
Offshore Structures ◽  
Full Scale ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Initial Imperfections ◽  
Numerical Predictions

Plated structures such as ships and offshore structures are constructed using welding techniques that attach support members (or stiffeners) to the plating. During this process, initial imperfections develop in the form of initial deformations (deflections or distortions) and residual stresses. These initial imperfections significantly affect the buckling and ultimate strength of these structures. Therefore, to assess the strength of welded plate structures, it is very important to predict the magnitude and pattern of welding-induced initial imperfections and their effects on buckling and ultimate strength. To determine the reliability of the prediction methods, it is desirable to validate the theoretical or numerical predictions of welding-induced initial imperfections through comparison with full-scale actual measurements. However, full-scale measurement databases are lacking, as they are costly to obtain. This study contributes to the development of a full-scale measurement database of welding-induced initial imperfections in steel-stiffened plate structures. The target structures are parts of real (full-scale) deckhouses in very large crude oil carrier class floating, production, storage and offloading unit structures. For parametric study purposes, four test structures by varying plate thickness are measured while the stiffener types and weld bead length are fixed. Modern technologies for measuring initial deformations and residual stresses are applied. The details of the measurement methods are documented for the use of other researchers and practicing engineers who want to validate their computational models for predicting welding-induced initial imperfections.

Sign in / Sign up

Export Citation Format

Share Document