Investigation on the nonlinear effects of the vertical motions and vertical bending moment for a wave-piercing tumblehome vessel based on a hydro-elastic segmented model test

2020 ◽  
Vol 72 ◽  
pp. 102757
Author(s):  
Hui Li ◽  
Baoli Deng ◽  
Huilong Ren ◽  
Shuzheng Sun
Keyword(s):  
Model Test ◽  
Bending Moment ◽  
Nonlinear Effects ◽  
Segmented Model ◽  
Vertical Bending Moment

Global Structural Loads Induced by Abnormal Waves and Design Storms on a FPSO

2006 ◽  
Author(s):  
Nuno Fonseca ◽  
Ricardo Pascoal ◽  
Carlos Guedes Soares
Keyword(s):  
North Sea ◽  
Time Domain ◽  
Probability Distributions ◽  
Bending Moment ◽  
Nonlinear Effects ◽  
Large Set ◽  
Scatter Diagram ◽  
Northern North Sea ◽  
Vertical Bending Moment ◽  
Classification Society

The structural loads on a FPSO induced by a large set of realistic (measured) abnormal waves are compared with the loads induced by “design storms” and also with the minimum values required by Classification Society rules. The design storms have a duration of 3 hours and correspond to the 100 years contour of the scatter diagram of the Northern North Sea. Time domain simulations are performed with a time domain seakeeping program that accounts for the most important nonlinear effects. The results are analyzed to obtain probability distributions of the sagging and hogging peaks of the vertical bending moment. Several theoretical distributions are fitted to the simulated realizations.

Global Structural Loads Induced by Abnormal Waves and Design Storms on a FPSO

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nuno Fonseca ◽  
Ricardo Pascoal ◽  
C. Guedes Soares
Keyword(s):  
North Sea ◽  
Time Domain ◽  
Probability Distributions ◽  
Bending Moment ◽  
Nonlinear Effects ◽  
Large Set ◽  
Scatter Diagram ◽  
Northern North Sea ◽  
Vertical Bending Moment ◽  
Classification Society

The structural loads on a floating production, storage, and offloading platform induced by a large set of realistic (measured) abnormal waves are compared with the loads induced by “design storms” and also with the minimum values required by Classification Society rules. The design storms have a duration of 3h and correspond to the 100yr contour of the scatter diagram of the Northern North Sea. Time domain simulations are performed with a time domain seakeeping program that accounts for the most important nonlinear effects. The results are analyzed to obtain probability distributions of the sagging and hogging peaks of the vertical bending moment. Several theoretical distributions are fitted to the simulated realizations.

A Method for Designing the Backbone for the Segmented Model of an Ultra-Large Container Carrier

2019 ◽  
Author(s):  
Hui Li ◽  
Jian Zou ◽  
Weijia Sheng ◽  
Xuecong Hu ◽  
Wenjia Hu
Keyword(s):  
Experimental Studies ◽  
Complex Form ◽  
Bending Moment ◽  
Torsional Stiffness ◽  
Mode Shapes ◽  
Wave Loads ◽  
Torsional Moment ◽  
Wave Load ◽  
Segmented Model ◽  
Vertical Bending Moment

Abstract The segmented model test is often used to study the wave load characteristics of large ships as it can account for the hydroealstic effect. The vertical bending moment (VBM) is of crucial importance in ensuring the safety of ocean-going vessels in rough seas, and there exists in the literature a large number of experimental studies of the VBM. For ships with large openings in the deck, for instance, container ships, the lateral wave loads, such as horizontal bending moment (HBM) and torsional moment (TM) in quartering seas, are as important as VBM. There are, however, few studies on the measurement of the coupled horizontal-torsional vibrations of such ships in model tests. In the paper, a method is proposed for designing flexible backbone models that satisfy the similarities of vertical and horizontal bending stiffness as well as the torsional stiffness, and the measurement of the wave load components is also described. In order to meet the similarity of the hull girder stiffness, the backbone cross-section of a complex form is designed. Finite element method (FEM) is used to calculate the natural frequencies and mode shapes of the segmented model. Measurement of the vertical bending moment, horizontal bending moment and torsional moment are calibrated by applying various combinations of loads.

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.

Joint High Speed Sealift (JHSS) Segmented Model Test Data Analysis and Validation of Numerical Simulations

2012 ◽  
Author(s):  
Dominic Piro ◽  
Kyle A. Brucker ◽  
Thomas T. O'Shea ◽  
Donald Wyatt ◽  
Douglas Dommermuth ◽  
...  
Keyword(s):  
Data Analysis ◽  
Numerical Simulations ◽  
Test Data ◽  
Model Test ◽  
High Speed ◽  
Segmented Model

scholarly journals Behavior Characteristics of Single Batter Pile under Vertical Load

2021 ◽  
Vol 11 (10) ◽  
pp. 4432
Author(s):  
Jiseong Kim ◽  
Seong-Kyu Yun ◽  
Minsu Kang ◽  
Gichun Kang
Keyword(s):  
Bearing Capacity ◽  
Relative Density ◽  
Model Test ◽  
Ground Surface ◽  
Bending Moment ◽  
Vertical Position ◽  
Vertical Load ◽  
Behavior Characteristics

The purpose of this study is to grasp the behavior characteristics of a single batter pile under vertical load by performing a model test. The changes in the resistance of the pile, the bending moment, etc. by the slope of the pile and the relative density of the ground were analyzed. According to the results of the test, when the relative density of the ground was medium and high, the bearing capacity kept increasing when the angle of the pile moved from a vertical position to 20°, and then decreased gradually after 20°. The bending moment of the pile increased as the relative density of the ground and the batter angle of the pile increased. The position of the maximum bending moment came closer to the ground surface as the batter angle of the pile further increased, and it occurred at a point of 5.2~6.7 times the diameter of the pile from the ground surface.

Load Combination for Fatigue Analysis of Ship Structures

2004 ◽  
Author(s):  
Yung S. Shin ◽  
Booki Kim ◽  
Alexander J. Fyfe
Keyword(s):  
Bending Moment ◽  
Linear Summation ◽  
Load Combination ◽  
Longitudinal Stiffeners ◽  
Stress Components ◽  
Tank Pressure ◽  
Wave Induced ◽  
Vertical Bending Moment ◽  
Oil Tanker

A methodology for calculating the correlation factors to combine the long-term dynamic stress components of ship structure from various loads in seas is presented. The methodology is based on a theory of a stationary ergodic narrow-banded Gaussian process. The total combined stress in short-tem sea states is expressed by linear summation of the component stresses with the corresponding combination factors. This expression is proven to be mathematically exact when applied to a single random sea. The long-term total stress is similarly expressed by linear summation of component stresses with appropriate combination factors. The stress components considered here are due to wave-induced vertical bending moment, wave-induced horizontal bending moment, external wave pressure and internal tank pressure. For application, the stress combination factors are calculated for longitudinal stiffeners in cargo and ballast tanks of a crude oil tanker at midship section. It is found that the combination factors strongly depend on wave heading and period in the short-term sea states. It is also found that the combination factors are not sensitive to the selected probability of exceedance level of the stress in the long-term sense.

scholarly journals Effect of Slam Force Duration on the Vibratory Response of a Lightweight High-Speed Wave-Piercing Catamaran

2015 ◽  
Vol 59 (02) ◽  
pp. 69-84
Author(s):  
Jason John McVicar ◽  
Jason Lavroff ◽  
Michael Richard Davis ◽  
Giles Thomas
Keyword(s):  
High Speed ◽  
Bending Strength ◽  
Experimental Studies ◽  
Bending Moment ◽  
Higher Order ◽  
Acute Angle ◽  
Beam Model ◽  
Higher Order Modes ◽  
Hull Structure ◽  
Vertical Bending Moment

When the surface of a ship meets the water surface at an acute angle with a high relative velocity, significant short-duration forces can act on the hull plating. Such an event is referred to as a slam. Slam loads imparted on ships are generally considered to be of an impulsive nature. As such, slam loads induce vibration in the global hull structure that has implications for both hull girder bending strength and fatigue life of a vessel. A modal method is often used for structural analysis whereby higher order modes are neglected to reduce computational effort. The effect of the slam load temporal distribution on the whipping response and vertical bending moment are investigated here by using a continuous beam model with application to a 112 m INCAT wave-piercing catamaran and correlation to full-scale and model-scale experimental data. Experimental studies have indicated that the vertical bending moment is dominated by the fundamental longitudinal bending mode of the structure. However, it is shown here that although the fundamental mode is dominant in the global structural response, the higher order modes play a significant role in the early stages of the response and may not be readily identifiable if measurements are not taken sufficiently close to the slam location. A relationship between the slam duration and the relative modal response magnitudes is found, which is useful in determining the appropriate truncation of a modal solution.

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