scholarly journals A New Formulation for Predicting the Collision Damage of Steel Stiffened Cylinders Subjected to Dynamic Lateral Mass Impact

2020 ◽  
Vol 10 (11) ◽  
pp. 3856
Author(s):  
Quang Thang Do ◽  
Van Vu Huynh ◽  
Mai The Vu ◽  
Vu Van Tuyen ◽  
Nhut Pham-Thanh ◽  
...  
Keyword(s):  
Energy Parameter ◽  
Lateral Mass ◽  
Test Results ◽  
Offshore Structure ◽  
Cylindrical Structures ◽  
Actual Design ◽  
Parametric Studies ◽  
New Formulation ◽  
Floating Objects ◽  
Local Dent

The objective of this study is to develop a new formulation for predicting the permanent local denting damage of steel ring and/or stringer-stiffened cylinders under dynamic lateral mass impact. The considered scenarios could represent the collisions of offshore cylindrical structures with bow or stern of service vessels or floating objects. Before deriving the formulations, the numerical methods were developed using ABAQUS/Explicit to determine the deformation of these stiffened cylinder structures subjected to dynamic lateral mass impact. Next, rigorous parametric studies were performed on the actual design full-scaled stiffened cylinder examples using the developed numerical method. Based on the rigorous numerical results, new simple design formulations to predict the maximum permanent local dent depth of a stiffened cylinder are derived through a regression study as the function of a non-dimensional energy parameter. The accuracy and reliability of the derived formulations are confirmed by comparison with the available test results, nonlinear FEA and existing analytical, and empirical equations in the literature. A good agreement with existing test data for ship-offshore structure collisions was achieved.

scholarly journals Deriving formulations for forecasting the ultimate strength of locally dented ring-stiffened cylinders under combined axial compression and radial pressure loads

2020 ◽  
Vol 23 (3) ◽  
pp. 640-654
Author(s):  
Do Quang Thang
Keyword(s):  
Ultimate Strength ◽  
Residual Strength ◽  
Good Accuracy ◽  
Uncertainty Modeling ◽  
Radial Pressure ◽  
Mean Value ◽  
Reduction Factor ◽  
The Novel ◽  
Test Results ◽  
Parametric Studies

Introduction: This paper focuses on the derived equations to evaluate the ultimate strength of ring-stiffened cylinders with local denting damage under combined loadings. The damage generation scenarios in this research are representing the collision accidents of offshore stiffened cylinders with supply ships. Methods: Numerical analysis of structures are performed using Abaqus software after validation against the experiments from the authors. The responses from seventeen cylinder specimens are analyzed to develop the numerical methods. Results: Good accuracy results were achieved when comparing the test results and the simulation results. Parametric studies are then performed on design examples of ring-stiffened cylinders when considering both intact and damaged conditions for assessing the reduction factor. Then, the novel simple design equations to assess the residual strength of ring-stiffened cylinders after ship collision are derived based on the regression analysis. These equations have good accuracy with mean value Xm (Uncertainty modeling factor) around 1.0 and together with COV (Coefficient of Variation) lower than 5.3%. Conclusion: The accuracy and reliability of the derived equations are validated by comparing it with the existing test data in open access. It is concluded that the proposed equations have high accuracy and reliability, and convenient application for the purpose of checking the residual strength of dented offshore cylinder under ship collisions.

scholarly journals Study on Evaluation for Collision Forces of Tsunami Floating Objects Acting on Cylindrical Structures

2014 ◽  
Vol 70 (2) ◽  
pp. I_961-I_965
Author(s):  
Takahide HONDA ◽  
Yukinobu ODA ◽  
Kazunori ITO ◽  
Hirotoshi OBI ◽  
Tomoyuki TAKABATAKE
Keyword(s):  
Cylindrical Structures ◽  
Floating Objects

Laboratory Testing of a Flexible Boom for Ice Management

1993 ◽  
Vol 115 (3) ◽  
pp. 149-153 ◽  
Author(s):  
S. Lo̸set ◽  
G. W. Timco
Keyword(s):  
Oil Spills ◽  
The Arctic ◽  
Small Scale ◽  
Test Results ◽  
Offshore Structure ◽  
Video Cameras ◽  
Ice Concentration ◽  
Broken Ice ◽  
Ice Field ◽  
Force Components

Combatting oil spills in the Arctic is a major challenge. Drilling or producing oil or gas in the marginal ice zone (MIZ) may allow booms to be deployed upstream of an offshore structure to clear the water of ice, thereby enabling conventional oil spill countermeasures to be used. Such a boom would be kept in place by two ice-going service vessels or by moored buoys. SINTEF NHL and NRC have performed a number of small-scale tests with a flexible boom in the NRC ice basin in Ottawa. The purpose of the tests was to measure the effectiveness of using a flexible boom for collecting ice, and to determine the loads associated with collecting the ice. In the tests, various boom configurations were towed against a broken ice field consisting of ice pieces typically 50–100 mm across and 30 mm thick. The ice concentration was usually 10/10, but it was reduced to 8/10 and 5/10 for two tests. The boom was towed at speeds of 20 and 50 mm-s−1. Both the width of the boom and the slackness of the boom were varied over reasonable ranges. Two six-component dynamometers were used to support the boom. Thus, the force components on each end of the boom were measured. Further, two video cameras were used to record the effectiveness of each boom configuration. In this paper, the full results of this test program are presented and the application of the test results to the full-scale situation are discussed. The tests show that, under certain conditions, the use of boom is feasible for ice management in oil-contaminated water.

Experimental and Numerical Study on the Flow Reduction in the Moonpool of Floating Offshore Structure

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Seon Oh Yoo ◽  
Hyun Joe Kim ◽  
Dong Yeon Lee ◽  
Booki Kim ◽  
Seung Ho Yang
Keyword(s):  
Numerical Study ◽  
Internal Flow ◽  
Navier Stokes ◽  
Test Results ◽  
Internal Flows ◽  
Offshore Structure ◽  
Flow Reduction ◽  
Gap Flow ◽  
Sloshing Mode ◽  
Computational Fluid Dynamics Cfd

Recently, drillship moonpools are getting longer and wider for the higher operability. With this trend, violent internal flows are getting more concerned in terms of the safety and operability, which have been reported during the operations even in mild seas. Also, it is well known that the internal flow gives higher resistance during the transit of drillship. In this study, to see the effect of larger damping devices, a series of experimental and numerical study was carried out for the four moonpool designs; the ordinary plain moonpool, the moonpool with a recess deck, the moonpool with an isolated recess deck (island deck), and moonpool with a combination of island deck, splash plates, and wave absorber. From the model tests, it was found that the internal flow of the moonpool was significantly reduced by the application of the wave absorber. In case of the moonpool with the island deck, the sloshing mode oscillations was not observed due to the gap flow between the inner wall of the moonpool and the recess. For the in-depth understanding of the flow behaviors and characteristics, the internal flow of the moonpool has been investigated using Reynolds-averaged Navier–Stokes based computational fluid dynamics (CFD) code. The various moonpool designs were simulated to identify the effect of each device for the internal flow reduction of the moonpool. The CFD analysis results with regular waves, the water surface responses inside moonpool such as the flow pattern and resonance frequency, were compared with model test results and showed reasonably good agreements.

Earthquake-induced hydrodynamic forces on reservoir roofs

2010 ◽  
Vol 37 (8) ◽  
pp. 1107-1115 ◽  
Author(s):  
Michael Isaacson
Keyword(s):  
Laboratory Test ◽  
Storage Tank ◽  
Water Surface ◽  
Design Procedure ◽  
Hydrodynamic Forces ◽  
Surface Elevation ◽  
Test Results ◽  
Hydrodynamic Loads ◽  
Laboratory Test Results ◽  
New Formulation

The present paper describes the hydrodynamic loads on the roof of a water-filled reservoir or storage tank due to earthquake-induced sloshing. Initially, the paper summarizes available solutions for the water surface elevation in a rectangular reservoir subjected to harmonic and earthquake base motions, and as well an available formulation for the force on the roof of a rectangular reservoir. With this background, a new formulation for the force on the roof is developed, and selected results based on this are presented. A recommended design procedure is thereby proposed, and an example application is provided. The potential extension of the proposed formulation to other reservoir configurations is discussed. Although a validation of the proposed formulation based on laboratory test results is needed, it is suggested that in the interim the proposed formulation is adopted for design.

Dynamic Analysis of Automotive Hypoid Gears

2013 ◽  
Author(s):  
I. Karagiannis ◽  
S. Theodossiades
Keyword(s):  
Dynamic Behaviour ◽  
Continuation Method ◽  
Transmission Error ◽  
Rear Wheel ◽  
Design Guidelines ◽  
Wheel Drive ◽  
Parametric Studies ◽  
Noise Vibration ◽  
New Formulation ◽  
Hypoid Gear Pairs

The dynamics of differentials in rear wheel drive vehicles are of major importance for the automotive industry. Hypoid transmissions — forming the motion transfer mechanism from the driveshaft to the wheels — often suffer from severe vibrations, which could lead to Noise, Vibration and Harshness (NVH) issues. The latter are often attributed to improper mesh between the mating gear flanks due to misalignments, variation of contact load and shifting of the effective mesh position. A new modelling approach on the torsional dynamics of hypoid gear pairs is presented in this work. This is characterised by an alternative expression of the Dynamic Transmission Error (DTE), which accounts for the variation of the effective mesh position. Numerical results indicate the enriched dynamic behaviour that can be predicted using the new formulation. A solution continuation method is employed to follow the response branches over the operating range of the differential under examination. The ensuing parametric studies convey the importance of the main system parameters on the dynamic behaviour of the differential, yielding suggestions for design guidelines.

Analysis of decay characteristics of an accumulator in an open-circuit hydrostatic system with pump loading

2017 ◽  
Vol 231 (4) ◽  
pp. 312-326 ◽  
Author(s):  
Ajit Kumar ◽  
K Dasgupta ◽  
J Das
Keyword(s):  
Open Circuit ◽  
Drive System ◽  
Test Results ◽  
System Pressure ◽  
Parametric Studies ◽  
Resistive Loads ◽  
Hydraulic Accumulator ◽  
Hydrostatic System ◽  
Mining Vehicles ◽  
Made In

The effects of the decay characteristics of a hydraulic accumulator on the responses of the hydrostatic drive system used in mining vehicles are studied in this article. The system considered for the analysis basically consists of a hydraulic pump, hydro-motor, accumulator and a loading circuit. The studies have been carried out with respect to two different sizes of accumulators. The system model has been made in MATLAB/Simulink® environment. The simulation test results are obtained with respect to the hydro-motor speeds and the system pressure at different resistive loads and capacities of the accumulator and they are verified with the experimental test data. Using the validated model, the parametric studies are also made on the speed responses of the hydrostatic drive for different precharge pressures of the accumulator and inertial load on the motor shaft. The studies made in this article may be useful for the selection of proper capacity of accumulators incorporated in the hydrostatic drive system in mining vehicles.

DYNAMIC RESPONSE OF METALLIC SANDWICH PANELS UNDER BLAST LOADINGS

2012 ◽  
Vol 12 (03) ◽  
pp. 1250017 ◽  
Author(s):  
HONGXIN WANG ◽  
XIAOXIONG ZHA ◽  
JIANQIAO YE
Keyword(s):  
Finite Element ◽  
Energy Balance ◽  
Dynamic Response ◽  
Analytical Method ◽  
Sandwich Panels ◽  
Fe Model ◽  
Test Results ◽  
Fluid Structure Interactions ◽  
Parametric Studies ◽  
Blast Loadings

An energy-balance-based analytical method and finite element (FE) simulations were developed in this paper to study the dynamic response of metallic sandwich panels subject to blast loadings. The analytical model can be used to predict approximately the deflection of the panels, while the FE model can take into account fluid–structure interactions and the effect of strain rate. Both models were validated by comparing their predictions with the test results available in the literature. Parametric studies were then carried out to assess various factors that are influential in characterizing the dynamic behavior of sandwich panels subject to blast loads.

Numerical Investigation on Structural Behaviour and Curling Influence of Aluminum Alloy Bolted Connections

2012 ◽  
Vol 166-169 ◽  
pp. 885-889 ◽  
Author(s):  
Tae Soo Kim ◽  
Yong Hyun Jo ◽  
Yun Cheol Choi
Keyword(s):  
Test Results ◽  
Strain Development ◽  
Bolted Connections ◽  
Structural Behaviour ◽  
Element Analysis ◽  
Edge Distance ◽  
End Distance ◽  
Parametric Studies ◽  
Structural Behaviors ◽  
Test Result

Numerical simulation is utilized to estimate the structural behaviors such as ultimate strength, fracture mode and curling effect of single shear bolted connections fabricated with aluminum alloys. In the Kim’s previous research, the validity of finite element analysis was verified through the comparison of test results and analysis results. In this paper, curling deformation and strain development between test result and analysis result were investigated. Also, additional parametric studies are performed for bolted connections with other variables of edge distance and end distance, which are not considered in the existing experiment. The conditions of end distance and edge distance for curing occurrence were discussed.

scholarly journals Analytical Solution for Stress and Displacement after X-Section Cast-in-Place Pile Installation

2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Hang Zhou ◽  
Han Long Liu ◽  
Gangqiang Kong ◽  
Zhaohu Cao
Keyword(s):  
Analytical Solution ◽  
Field Test ◽  
Horizontal Stress ◽  
Soil Disturbance ◽  
Test Results ◽  
Pile Installation ◽  
Present Solution ◽  
Parametric Studies ◽  
New Type ◽  
Surrounding Soil

X-section cast-in-place (referred to as XCC) pile, which is one of new pile types developed by Hohai University, is widely used for pile foundation and pile-supported embankment over soft ground in China. However, little research has been carried out on this new type pile, especially the surrounding soil disturbance under XCC pile installation. This paper presents an analytical solution for estimating the horizontal stress and displacement of surrounding soil of XCC pile after XCC pile installation. The reliability and accuracy of the present solution are verified by comparing them with the field test results. Then, parametric studies, such as outsourcing diameter(a), open arc distance(b), open arc angle(θ), the undrained strength(Su), the limit pile cavity pressure(Plim), and the radius of the plastic zone(Rp), are discussed for the practice engineering design. The results show that the stress and displacement distributions of surrounding soil calculated by this paper are in agreement with field test results.

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