A Segmented Ship Model: Experimental Research on Hydroelastic Effect of a Large Ship in Wave

2018 ◽  
Author(s):  
Ying Tang ◽  
Shili Sun ◽  
Kai Jin ◽  
Zheng Yang ◽  
Huilong Ren
Keyword(s):  
Experimental Research ◽  
Bending Moment ◽  
Ship Hull ◽  
Regular Wave ◽  
Ship Model ◽  
Large Ship ◽  
Time Histories ◽  
Series Of Experiments ◽  
The Impact ◽  
Vertical Bending Moment

In this paper, rigid ship hull and elastic ship hull were respectively designed. For the former, the hull is divided into two segments, while for the latter, into five segments. And a series of experiments of ship model navigating in regular wave were carried out. Time histories of motion and vertical bending moment of the two models were recorded and analyzed. By comparing results of the two models, the impact of elasticity of hull grider on motion and vertical bending moment can be analyzed.

Improvement of Wave Loads Estimation From Spatial Pressure Distribution on Ship Hull

2019 ◽  
Author(s):  
Kurniawan T. Waskito ◽  
Masashi Kashiwagi
Keyword(s):  
Pressure Distribution ◽  
Pressure Sensors ◽  
Estimation Method ◽  
Bending Moment ◽  
Ship Hull ◽  
Accurate Estimation ◽  
Wave Loads ◽  
Local Pressure ◽  
Shipbuilding Industry ◽  
Vertical Bending Moment

Abstract In modern shipbuilding industry, merchant ships tend to increase in size. Accurate prediction of the vertical bending moment in large-maplitude waves has become important for structural design. For establishment of an accurate estimation method, more detailed local hydrodynamic quantities such as the spatial pressure distribution on the whole ship hull surface should be checked. For that purpose, the experiment has been conducted by means of Fiber Bragg Grating (FBG) sensing technology. Using the measured local pressure distribution by only sticking the FBG pressure sensors onto the hull surface, we can evaluate the wave loads; which may lead to establishment of a new evaluation method for the wave loads without using a segmented model. We confirm favorable agreement of the pressure distribution between measurement and computation by Rankine Panel Method (RPM). Furthermore, the vertical bending moment computed at some transverse sections shows favorable agreement between measured and computed results.

Ship Hull Bottom Slamming

1995 ◽  
Vol 117 (4) ◽  
pp. 252-259 ◽  
Author(s):  
P. Rassinot ◽  
A. E. Mansour
Keyword(s):  
Normal Modes ◽  
Bending Moment ◽  
Simple Expression ◽  
Ship Hull ◽  
Hydrodynamic Load ◽  
Maximum Value ◽  
Strip Theory ◽  
The Impact ◽  
Increasing Function ◽  
Free Beam

A method is presented to evaluate the hull bending moment due to bottom slamming. Theoretical explanations and updates are given to the commonly used empirical results, and some observations are made on slamming. An energy approach combined with a strip theory is used to get the hydrodynamic load, and to analyze the effects of the forward velocity. Impacts of simple bodies are simulated numerically to describe these loads. The ship hull is represented as a nonuniform free-free beam, and its response is decomposed into normal modes; only the contribution of the first one is kept. In a numerical example, the bending moment during the impact is determined. It is shown that its value when the impact is over is much harder to predict. The maximum value of the bending moment, however, occurs during the impact, and is an increasing function of the vertical velocity, as expected. A simple expression is given for it.

scholarly journals Study on Longitudinal Ship Strength Caused by the Placement of Beams and Girders on Upper Deck Side

2018 ◽  
Vol 1 (2) ◽  
pp. 74-80
Author(s):  
Andi Ardianti ◽  
Andi Mursid Nugraha ◽  
Ganding Sitepu ◽  
Hamzah Hamzah ◽  
Ade Khantari ◽  
...  
Keyword(s):  
Structural Response ◽  
Bending Moment ◽  
Ship Model ◽  
Upper Deck ◽  
Deck Plate ◽  
Longitudinal Strength ◽  
Moment Load ◽  
Vertical Bending Moment ◽  
Beams And Girders ◽  
Classification Society

The location of the beam and the deck girder of the ship can be effect on it is strength especially for the longitudinal strength due to the vertical wave bending moment. The objective of this study is to know the structural response of the ship due to vertical bending moment load on hogging and sagging conditions. The analysis is carried out by using Finite Element Method so-called ANSYSTM. The results shows that the stress occurring on the ship model with deck beam above the deck plate is larger than the ship model with deck beam under the deck plate. When the load with the variated of 0.2 x moment of vertical moment load, there is an increase of stress that occurs both on the deck area about 12% while on the bottom area about 0.98%. This study also conducted a stress comparison by using analysis methods with analytical methods. The results show that by the Stress differences that occur in the structure with the longitudinal deck beam and deck girder above are 14.1% on the deck and 7.1 on the bottom. Whereas in the structure with deck longitudinal deck eam and deck girder under there is a difference of 5.7% on the deck area and 3.5% in the bottom area of the ship. The stress that occur in both models have a difference that is not too far away and still under the permisible stress by the classification society so that both can be applied to the construction of a tanker.

Design and Make of a Segmented Ship Model for Vertical Bending Moment Measurement

2018 ◽  
Author(s):  
Jingxia Yue ◽  
Yulong Guo ◽  
Lihua Peng
Keyword(s):  
Model Test ◽  
Large Scale ◽  
Bending Moment ◽  
Structural Safety ◽  
Scale Model ◽  
Wave Load ◽  
Scaled Model ◽  
Ship Model ◽  
Section Modulus ◽  
Vertical Bending Moment

With the development of the large-scale ship, the hull becomes more and more “soft” and “elastic”. Accurate simulation of ship’s hydro-elastic performance through scaled model test plays an important role in structural safety assessment. This paper presents the detail preparation of a segmented model which is used to investigate the vertical bending moment (VBM) for a 260m TEU container ship. Some innovative concepts were involved in the scaled model design. Firstly, the segmentation of the ship model was based on the hull’s vertical vibration mode for better simulation of the hull’s rigidity distribution. Secondly, the section of the backbone beam was varied by polishing along ship length in order to simulate the varied section modulus of ship hull. Thirdly, new backbone fixed type was carried out by two flange plates for a better wave load transmission. Besides, some useful techniques were provided, including the model making technique, calibration technique, and backbone system technique. It increases the feasibility of test, at a certain extent. Finally, an overview of the ongoing large scale model test plan and its future development directions is prospected.

Prediction of nonlinear vertical bending moment using measured pressure distribution on ship hull

2020 ◽  
Vol 101 ◽  
pp. 102261
Author(s):  
Kurniawan T. Waskito ◽  
Masashi Kashiwagi ◽  
Hidetsugu Iwashita ◽  
Munehiko Hinatsu
Keyword(s):  
Pressure Distribution ◽  
Bending Moment ◽  
Ship Hull ◽  
Measured Pressure ◽  
Vertical Bending Moment

THE EFFECT OF METACOGNITIVE INSTRUCTION ON MAXIMIZING EFL LEARNERS’ METACOGNITIVE AWARENESS IN LISTENING

2018 ◽  
Vol 7 (1) ◽  
pp. 8-17
Author(s):  
Mahsa Assadi
Keyword(s):  
Experimental Research ◽  
Listening Comprehension ◽  
Intervention Program ◽  
Metacognitive Awareness ◽  
Listening Test ◽  
Efl Learners ◽  
Metacognitive Instruction ◽  
Before And After ◽  
Comprehension Ability ◽  
The Impact

This study reports a pre-experimental research on the impact of metacognitive instruction on EFL learners’ metacognitive awareness and their listening performance. To obtain the goal of the study, a group of 30 Iranian intermediate EFL learners, including 14 males and 16 females, were selected randomly. Their ages range from 20 to 24. The participants took part in 16 weeks’ intervention program based on metacognitive pedagogical sequence consisted of five stages. The metacognitive awareness listening questionnaire (MALQ), and a listening test were also used to find changes in metacognitive awareness and listening performance before and after the treatment. The results of comparing pre and posttests scores revealed that metacognitive instruction raised the learners’ metacognitive awareness and helped them improve their listening comprehension ability.

The Impact of the Industrial Processing of Oil on the Rainfall Water Quality

2017 ◽  
Vol 68 (1) ◽  
pp. 175-179
Author(s):  
Oana Roxana Chivu ◽  
Augustin Semenescu ◽  
Claudiu Babis ◽  
Catalin Amza ◽  
Gabriel Iacobescu ◽  
...  
Keyword(s):  
Water Quality ◽  
Sulfuric Acid ◽  
Experimental Research ◽  
Air Purification ◽  
High Toxicity ◽  
Industrial Processing ◽  
Mobile Sources ◽  
Specific Activities ◽  
The Impact ◽  
The Ideal

Rainfall is a major component of the environment and the main source of the air purification becouse of many pollutants increases who have the most varied sources: various human activities including industry and agriculture, and some household duties. Air purification by means of precipitation is achieved by numerous highly complex mechanisms. The final products of degradation of the pollutant in the air, which are generally harmless, can be reacted with each other in the presence of water, giving rise to the final compounds with a high toxicity. Thus, exhaust, mobile sources of noxious almost identical to those specific activities in the industrial processing of oil, contain lead which is the ideal catalyst for converting SO2 to sulfuric acid in the presence of rainwater, with all the disadvantages that they create. This paper will present an experimental research oabout how rainfall water quality is influenced by the activity of the industrial processing of oil, in a chemical plant in Constanta County.

scholarly journals Driven Pile Effects on Nearby Cylindrical and Semi-Tapered Pile in Sandy Clay

2021 ◽  
Vol 11 (7) ◽  
pp. 2919
Author(s):  
Massamba Fall ◽  
Zhengguo Gao ◽  
Becaye Cissokho Ndiaye
Keyword(s):  
Coupling Effect ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Adaptive Mesh ◽  
Pile Driving ◽  
Arbitrary Lagrangian Eulerian ◽  
Axial Forces ◽  
Tapered Pile ◽  
Driven Pile ◽  
The Impact

A pile foundation is commonly adopted for transferring superstructure loads into the ground in weaker soil. They diminish the settlement of the infrastructure and augment the soil-bearing capacity. This paper emphases the pile-driving effect on an existing adjacent cylindrical and semi-tapered pile. Driving a three-dimensional pile into the ground is fruitfully accomplished by combining the arbitrary Lagrangian–Eulerian (ALE) adaptive mesh and element deletion methods without adopting any assumptions that would simplify the simulation. Axial forces, bending moment, and lateral displacement were studied in the neighboring already-installed pile. An investigation was made into some factors affecting the forces and bending moment, such as pile spacing and the shape of the already-installed pile (cylindrical, tapered, or semi-tapered). An important response was observed in the impact of the driven pile on the nearby existing one, the bending moment and axial forces were not negligible, and when the pile was loaded, it was recommended to consider the coupling effect. Moreover, the adjacent semi-tapered pile was subjected to less axial and lateral movement than the cylindrical one with the same length and volume for taper angles smaller than 1.0°, and vice versa for taper angles greater than 1.4°.

Experimental Study of a Tanker Ship Squat in Shallow Water

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Mohammadreza Fathi Kazerooni ◽  
Mohammad Saeed Seif
Keyword(s):  
Experimental Study ◽  
Shallow Water ◽  
Experimental Approach ◽  
Model Tests ◽  
Ship Hull ◽  
Experimental Results ◽  
Shallow Waters ◽  
Towing Tank ◽  
Ship Model

One of the phenomena restricting the tanker navigation in shallow waters is reduction of under keel clearance in the terms of sinkage and dynamic trim that is called squatting. According to the complexity of flow around ship hull, one of the best methods to predict the ship squat is experimental approach based on model tests in the towing tank. In this study model tests for tanker ship model had been held in the towing tank and squat of the model are measured and analyzed. Based on experimental results suitable formulae for prediction of these types of ship squat in fairways are obtained.

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