scholarly journals Numerical Simulation of the Ice Breaking Process for Hovercraft

2021 ◽  
Vol 9 (9) ◽  
pp. 928
Author(s):  
Jiangjie Jin ◽  
Li Zhou ◽  
Shifeng Ding ◽  
Yingjie Gu
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Open Water ◽  
Structural Safety ◽  
Preliminary Design ◽  
Load Prediction ◽  
Ice Load ◽  
Hull Structure ◽  
Air Cushion ◽  
Ice Force

A hovercraft can adapt to an ice area, open water, land and other environments, owing to its unique hull structure. It also plays an important role in transporting supplies, rescuing people, breaking ice and conducting other tasks. Ice load prediction is very important for structural safety and navigation of a polar ship, especially in design of air cushion icebreakers or ice breaking platforms. In this paper, based on a simplified circumferential icebreaking pattern, the icebreaking force of the hovercraft operating on the ice sheet at low speed is simulated in a numerical way. Numerical analysis of the icebreaking process with different ice thicknesses and bending strengths are performed. The numerical results are compared with model test data in a time domain for three operating cases. By analyzing the average ice force, the errors between numerical simulation results and model test measurements are less than 30%. The present study is significant for the preliminary design of new icebreaking hovercraft and it assists the operation possibility for existing hovercraft.

Development of Ice Class Arc4 MK III™ Type LNG Carrier

2008 ◽  
Author(s):  
Yongsuk Suh ◽  
Kibok Jang ◽  
Hisashi Ito ◽  
Seungmun Park ◽  
Sungyong Han ◽  
...  
Keyword(s):  
High Reliability ◽  
Direct Calculation ◽  
Arctic Region ◽  
Structural Safety ◽  
Wave Loads ◽  
Extreme Wave ◽  
Ice Load ◽  
Containment System ◽  
Hull Structure ◽  
Ice Loads

It is a very challenging work to design 208K Arctic LNG carrier, since LNG carrier requires high reliability for the structural safety and the environment of Arctic region is known to be very severe. Therefore, special attention should be paid for the verifying the structural safety of LNG carrier particularly with regard to LNG leakage. In this paper, the safety of the hull structure and cargo containment system of 208K MK III™ type LNG carriers with Arc4 is investigated based on the direct calculation of ice loads as well as wave loads. Several scenarios like design ice load, accidental ice load, ramming, entrapment and extreme wave are considered. From the whole investigation, it is clear that the developed vessel — 208K MK III™ type LNG carrier with RMRS Ice class Arc4 — has enough strength and is safe to be operated in Arctic region.

scholarly journals Establishment and Verification of a Constitutive Model of Ice Material Considering the Effect of Temperature

2020 ◽  
Vol 8 (3) ◽  
pp. 193
Author(s):  
Tongqiang Yu ◽  
Kun Liu ◽  
Jiaxia Wang ◽  
Zili Wang
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Arctic Region ◽  
Structure Design ◽  
Structural Deformation ◽  
The Arctic ◽  
Effect Of Temperature ◽  
Load Prediction ◽  
Finite Element Software ◽  
Ice Load

The increase in global warming has secured the arctic region as a research hotspot, and the existence of ice floes and massive icebergs poses a great challenge to the navigational safety of polar ships. For the finite simulation of ship–ice collisions, a reasonable description of the ice constitutive model is the most important factor for the accuracy of ice load prediction and structural deformation assessment. Due to the complex physical properties of natural sea ice materials, there are still many difficulties in achieving a widely accepted ice material model. In this paper, a constitutive model of ice material considering the influence of temperature is established and embedded into finite element software LS-DYNA, and the material property parameters are validated and analyzed. Then, the drop test in a published paper is recapitulated by the numerical simulation with the proposed method, and the results are compared. Good agreement is attained between the numerical simulation and published results. The influences of temperature and drop height are discussed, and the results show that both of them have an important effect on structural deformation. The research results can be used for ice load prediction and polar ship structure design.

Numerical simulation of ice-induced vibrations of steady-state type

2019 ◽  
Vol 22 (12) ◽  
pp. 2635-2647
Author(s):  
Wenliang Qiu ◽  
Tianyu Wu
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Model Test ◽  
Simulation Method ◽  
Offshore Structures ◽  
Structural Safety ◽  
Simulation Methodology ◽  
State Type ◽  
Ice Floes ◽  
Ice Pressure

Ice force is one kind of nonnegligible external loads that nature exerts on structures. The action of drifting ice floes may induce strong vibrations of offshore structures, and further reduce the structural safety and serviceability. The aim of this article is to develop a method to simulate the most dangerous situation during the interaction between ice and structure, that is, the ice-induced vibrations of steady-state type. A simulation methodology to realize structural steady-state vibration is proposed; it can simulate a special phenomenon of negative damping. The calculation of effective ice pressure is accomplished by an empirical formula which considers the dependence of the crushing strength on the ice velocity. The most important contribution of the simulation method is to capture the steady-state vibration phenomenon. The presented simulation methodology is conducted on the same model test introduced in a referenced study to verify the efficacy. Calculational examples show good agreements with the results of the model test, and the frequency contents of the generations coincide well with the targets. They directly prove the validity of the proposed simulation method. In addition, the numerical simulation method can be used in connection with finite element programs to perform a steady-state vibration analysis of offshore structures.

Case Study on Modeling Fire Action Complexity in Fire Safety Engineering of Structures

2017 ◽  
Vol 21 ◽  
pp. 102-107
Author(s):  
Constantin Sorin Scutarasu ◽  
Dan Diaconu-Şotropa ◽  
Marinela Barbuta
Keyword(s):  
Numerical Simulation ◽  
Fire Safety ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Structural Safety ◽  
Modular Organization ◽  
Field Of Study ◽  
Safety Design ◽  
Fire Safety Design ◽  
Technical Regulations

Important goals in the fire safety design, such as preventing loss of life and goods damage, are achieved by maintaining the stability of structures exposed to fire for a period of time established by norms and standards. Real fire scenarios confirm that the specific technical regulations which actually have a prescriptive character (both national and international) do not deal with sufficient possibilities regarding the assessment of structural fire safety. The new approach on structural safety, based on engineering notions, gives us additional prospects on it and it is included in the issues of the fire safety design of structures. A relatively new field of study, known by a few professionals focused on fire safety (but well acknowledged in the research area), fire safety design met with lots of changes and restructuring of the governing concepts and procedures and of the information with which they operate, due to the fast accumulation of experience in this area of engineering activity. Consequently, after countries such as Australia, Canada, New Zeeland or USA provided towards professionals specific technical regulations for fire safety design, groups of experts in these aforementioned countries have joined their forces to try to diminish the differences that exists between those regulations and to give a unitary character to them, a better conceptualized engineering approach of the fire safety design. The result: occurrence of the publication International Fire Engineering Guidelines (last edition from 2005). The systematic approach of fire safety design in constructions pointed, once again, the possibility of modular organization of this field of study, the relations between modules being established according to the objective or objectives in the fire safety design for a specified building. This article aims to put forward, from this modularized perspective, the study of the fire safety design of a building exposed to fire; hence, the practical part of the article exhibits the numerical simulation of initialization and development of the fire process for a large scale religious building. The main features of the building represent the amount of space that facilitates the spreading of smoke and warm gases and which increases the risk of damaging the structural reinforced concrete elements. Application calls to specific numerical simulation with a higher degree of credibility, such as those realized by the FDS (Fire Dynamics Simulation) software.

Numerical Simulation of Ship Collision and Validations With Experimental Results

2021 ◽  
Author(s):  
Xiangbiao Wang ◽  
Chun Bao Li ◽  
Ling Zhu
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Structural Damage ◽  
Added Mass ◽  
Ship Motion ◽  
Time Dependent ◽  
Structural Deformation ◽  
Structure Interaction ◽  
Ship Collision ◽  
Good Agreement

Abstract Ship collision accidents occur from time to time in recent years, and this would cause serious consequences such as casualties, environmental pollution, loss of cargo on board, damage to the ship and its equipment, etc. Therefore, it is of great significance to study the response of ship motion and the mechanism of structural damage during the collision. In this paper, model experiments and numerical simulation are used to study the ship-ship collision. Firstly, the Coupled Eulerian-Lagrangian (CEL) was used to simulate the fluid-structure interaction for predicting structural deformation and ship motion during the normal ship-ship collision. Meanwhile, a series of model tests were carried out to validate the numerical results. The validation presented that the CEL simulation was in good agreement with the model test. However, the CEL simulation could not present the characteristics the time-dependent added mass.

Outlier analysis of sloshing impact loads on liquid ship cargo

2022 ◽  
pp. 147509022110695
Author(s):  
Sang-Yeob Kim ◽  
Yonghwan Kim ◽  
Yang-Jun Ahn
Keyword(s):  
Model Test ◽  
Present Method ◽  
Treatment Method ◽  
Liquefied Natural Gas ◽  
Impact Loads ◽  
Test Results ◽  
Outlier Analysis ◽  
Load Prediction ◽  
Conventional Procedure

This paper introduces an outlier analysis which can improve the convergence of the statistical analysis results of sloshing model test data. The paper classify possible outliers in the sloshing model test into three categories and present a treatment method for each outlier. The developed outlier analysis is adapted to the model test results for the cargo of the liquefied-natural-gas (LNG) carrier in operation. The results of the present new method are compared with those of the conventional procedure, particularly focusing on long-term sloshing prediction. Through this study, the effectiveness of the present method is observed, and it is found that the present method provides is robust and reliable results in the application of experimental data for load prediction.

Study on Similar Skills of Dynamic Model Test Concerning Fluid-Structure Interaction for Water-Conveyance Tunnel in Soft Soil

2010 ◽  
Vol 29-32 ◽  
pp. 1458-1463 ◽  
Author(s):  
Jin Yun Liu ◽  
Jian Yun Chen
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Structural Model ◽  
Soft Soil ◽  
Fluid Structure Interaction ◽  
Similar Relationship ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Water Conveyance ◽  
Water Conveyance Tunnel

Three basic types of similar relationship between the prototype and the model for dynamic structural model test and dynamic destructive model test were proposed in corresponding literatures. At the time the situation where various similar relationships are applicable and the technique to ensure similarity for the different goal was discussed. Here the numerical simulation of model test of water-conveyance tunnel concerning fluid-structure interaction in soft soil is studied. Based on economy and practicability of selective material for model test, the similar relationship and the technique are proposed, which are validated through the example. The results of numerical simulation show: under the specific conditions, data of the model test can completely transfer to those of the prototype by use of this type of similar skill, and get more useful information. Some new ideas are introduced to keep the similarity of the hydro-structure structures.

Station Keeping Trials in Ice: Ice Load Monitoring System

2018 ◽  
Author(s):  
Håvard Nyseth ◽  
Anders Hansson ◽  
Johan Johansson Iseskär
Keyword(s):  
Data Sets ◽  
Station Keeping ◽  
Ice Load ◽  
Hull Structure ◽  
Load Monitoring ◽  
Ice Loads ◽  
Recorded Data ◽  
Measurement Concept ◽  
Ice Impacts ◽  
Basic Philosophy

In connection with the Statoil SKT project, DNV GL have developed a method for estimating ice loads on the ship hull structure and mooring tension of the anchor handling tug supply (AHTS) vessel Magne Viking by full scale measurements. In March 2017, the vessel was equipped with an extensive measurement system as a preparation for the dedicated station-keeping trial in drifting ice in the Bay of Bothnia. Data of the ice impacts acting on the hull were collected over the days of testing together with several other parameters from the ship propulsion system. Whilst moored, the tension in the mooring chain was monitored via a load cell and logged simultaneously to the other parameters. This paper presents the processes involved in developing the measurement concept, including the actual installation and execution phases. The basic philosophy behind the system is described, including the methods used to design an effective measurement arrangement, and develop procedures for estimation of ice loads based on strain measurements. The actual installation and the process of obtaining the recorded data sets are also discussed.

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