scholarly journals Evaluating structural crashworthiness and progressive failure of double hull tanker under accidental grounding: bottom raking case

2018 ◽  
Vol 8 (1) ◽  
pp. 193-204 ◽  
Author(s):  
Aditya Rio Prabowo ◽  
Hyun Jin Cho ◽  
Seung Geon Lee ◽  
Seung Jun Baek ◽  
Jung Hoon Byeon ◽  
...  
Keyword(s):  
Structural Damage ◽  
Sea Water ◽  
Marine Pollution ◽  
Progressive Failure ◽  
High Sensitivity ◽  
Geometrical Parameters ◽  
Structural Development ◽  
Structural Behaviour ◽  
Oil Spillage ◽  
Double Hull

Abstract Remarkable consequences of maritime accident can be various, including structural damage, loss of life and marine pollution. During an accidental phenomenon, such as ship grounding, the amount of oil spillage indicates casualties’ extent of surrounding sea water. Effort to provide protection for sea environment against such event has been conducted actively by developing navigational instruments, and passively using structural development and assessment. The accidental grounding is, however, a very complicated process with high sensitivity to given factors during its occurrence. Variety in ship type, location, obstruction etc. affected by advance improvement in naval technology, invites sustainable analysis for structural crashworthiness and failure to produce evaluation data. This work aims to perform an assessment on double hull tanker subjected accidental grounding with oceanic seabed as the obstruction. Fundamental concept of bottom raking is used to design grounding scenario using numerical experiment. Non-Linear Finite Element Method (NLFEM) is deployed to idealise tanker structure and obstruction geometry. The selected crashworthiness criteria in grounding are summarised to provide structural prediction in moment double hull members are experiencing crushing process. Influence of geometrical parameters’ variation to progressive failure is presented with contribution of double bottom members to structural behaviour in final part. Result data of the current work can be a reasonable reference to understanding double bottom performance in grounding, especially in raking case. Insight of such accidental phenomenon is very useful in further effort to minimise grounding consequences.

Development of Rapid Prediction Method for Residual Strength of Oil Tankers Subjected to Ship-Ship Collision

2018 ◽  
Author(s):  
Seung Jun Baek ◽  
Jung Min Sohn ◽  
Jeom Kee Paik ◽  
Sang Jin Kim
Keyword(s):  
Empirical Formula ◽  
Structural Damage ◽  
Marine Pollution ◽  
Prediction Method ◽  
Financial Loss ◽  
Hull Girder ◽  
Special Skill ◽  
Oil Tankers ◽  
Marine Accidents ◽  
Double Hull

Collision and grounding accidents account for more than half of all accident cases in most cases. Such marine accidents cause severe structural damage to the ship and lead to marine pollution as well as life and financial loss. For preventing the loss of property and pollution, and preparing a countermeasure, it is needed to predict a residual hull girder strength after accident regardless of someone’s special skill. The aims of this study are to i) investigate the residual hull girder strength by quantitative approach with collision location (height and penetration), ii) develop an empirical formula for calculating a residual hull girder strength which whoever can calculate in association with collision locations. In this study, three kinds of ships such as very large crude oil carrier, Suezmax, and Aframax class double hull oil tankers are selected as target struck vessels. And, the Intelligent Supersize Finite Element Method (ISFEM) is applied to assess the residual hull girder strength of damaged structures after collisions. Based on the ISFEM results, an empirical formula for calculation of residual hull girder strength is developed as a function of the collision depth and penetration. The developed formula in this study can be applied by anyone, and rapidly calculate its strength for preventing sequential events (collapse, fuel spill, etc.) after collision.

scholarly journals Neurotoxicity in Marine Invertebrates: An Update

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 161
Author(s):  
Irene Deidda ◽  
Roberta Russo ◽  
Rosa Bonaventura ◽  
Caterina Costa ◽  
Francesca Zito ◽  
...  
Keyword(s):  
Nervous System ◽  
Marine Invertebrates ◽  
Marine Pollution ◽  
Marine Invertebrate ◽  
High Sensitivity ◽  
Model Systems ◽  
Neural Genes ◽  
Chemical Agents ◽  
Neurotoxic Effects ◽  
Invertebrate Model

Invertebrates represent about 95% of existing species, and most of them belong to aquatic ecosystems. Marine invertebrates are found at intermediate levels of the food chain and, therefore, they play a central role in the biodiversity of ecosystems. Furthermore, these organisms have a short life cycle, easy laboratory manipulation, and high sensitivity to marine pollution and, therefore, they are considered to be optimal bioindicators for assessing detrimental chemical agents that are related to the marine environment and with potential toxicity to human health, including neurotoxicity. In general, albeit simple, the nervous system of marine invertebrates is composed of neuronal and glial cells, and it exhibits biochemical and functional similarities with the vertebrate nervous system, including humans. In recent decades, new genetic and transcriptomic technologies have made the identification of many neural genes and transcription factors homologous to those in humans possible. Neuroinflammation, oxidative stress, and altered levels of neurotransmitters are some of the aspects of neurotoxic effects that can also occur in marine invertebrate organisms. The purpose of this review is to provide an overview of major marine pollutants, such as heavy metals, pesticides, and micro and nano-plastics, with a focus on their neurotoxic effects in marine invertebrate organisms. This review could be a stimulus to bio-research towards the use of invertebrate model systems other than traditional, ethically questionable, time-consuming, and highly expensive mammalian models.

scholarly journals A High Sensitivity Self-Powered Wind Speed Sensor Based on Triboelectric Nanogenerators (TENGs)

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2951
Author(s):  
Yangming Liu ◽  
Jialin Liu ◽  
Lufeng Che
Keyword(s):  
Wind Speed ◽  
High Sensitivity ◽  
Electrical Signal ◽  
Geometrical Parameters ◽  
Sensor Systems ◽  
Speed Sensor ◽  
Speed Range ◽  
Self Powered ◽  
Triboelectric Nanogenerators ◽  
Application Prospects

Triboelectric nanogenerators (TENGs) have excellent properties in harvesting tiny environmental energy and self-powered sensor systems with extensive application prospects. Here, we report a high sensitivity self-powered wind speed sensor based on triboelectric nanogenerators (TENGs). The sensor consists of the upper and lower two identical TENGs. The output electrical signal of each TENG can be used to detect wind speed so that we can make sure that the measurement is correct by two TENGs. We study the influence of different geometrical parameters on its sensitivity and then select a set of parameters with a relatively good output electrical signal. The sensitivity of the wind speed sensor with this set of parameters is 1.79 μA/(m/s) under a wind speed range from 15 m/s to 25 m/s. The sensor can light 50 LEDs at the wind speed of 15 m/s. This work not only advances the development of self-powered wind sensor systems but also promotes the application of wind speed sensing.

scholarly journals High Sensitivity Plasmonic Sensor Based on Fano Resonance with Inverted U-Shaped Resonator

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1164
Author(s):  
Gongli Xiao ◽  
Yanping Xu ◽  
Hongyan Yang ◽  
Zetao Ou ◽  
Jianyun Chen ◽  
...  
Keyword(s):  
Fano Resonance ◽  
Figure Of Merit ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Multimode Interference ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Plasmonic Sensor ◽  
Coupled Mode ◽  
Plasmonic Nanosensor

Herein, we propose a tunable plasmonic sensor with Fano resonators in an inverted U-shaped resonator. By manipulating the sharp asymmetric Fano resonance peaks, a high-sensitivity refractive index sensor can be realized. Using the multimode interference coupled-mode theory and the finite element method, we numerically simulate the influences of geometrical parameters on the plasmonic sensor. Optimizing the structure parameters, we can achieve a high plasmonic sensor with the maximum sensitivity for 840 nm/RIUand figure of merit for 3.9 × 105. The research results provide a reliable theoretical basis for designing high sensitivity to the next generation plasmonic nanosensor.

Numerical Simulation of Sloshing of Water in Ship Tanks During Sequential Ballast Water Exchange in Seaways

2002 ◽  
Author(s):  
Makoto Arai ◽  
Humberto S. Makiyama ◽  
Liang-Yee Cheng
Keyword(s):  
Ballast Water ◽  
Water Exchange ◽  
Sea Water ◽  
Marine Pollution ◽  
Aquatic Organisms ◽  
Exchange Method ◽  
Ballast Tank ◽  
Open Sea ◽  
Merchant Ship ◽  
Ballast Tanks

In recent years, ballast water has been blamed for a variety of marine pollution problems, particularly for transporting harmful aquatic organisms from one part of the world to another and damaging the ecosystem of the new areas. A relatively simple mechanism to control this problem is to exchange ballast water on the high seas between ports in order to remove invasive species before the ship reaches its destination. However, some issues regarding ballast exchange on the open sea need to be addressed before this operation is introduced. One of them is the sloshing of the sea water in the ballast tank. In this paper, ballast water exchange on the open sea by means of the Sequential exchange method is simulated. Irregular seaways are generated from the ISSC spectrum, and the sloshing response of the water in the ballast tanks of a large merchant ship is numerically computed by using a finite difference code developed by the authors. The results showed that there is little possibility that severe sloshing presents a serious problem in regard to the ballast tank’s strength, especially in the case of a bulk carrier whose tanks are generally short in length, with sloshing anticipated only at the low water level.

Research on Collision Mechanism for a Ship Colliding With a Spar Platform

2007 ◽  
Author(s):  
Zhiqiang Hu ◽  
Weicheng Cui ◽  
Longfei Xiao ◽  
Jianmin Yang
Keyword(s):  
Numerical Simulation ◽  
Structural Damage ◽  
Simulation Method ◽  
Hydrodynamic Characteristics ◽  
Spar Platform ◽  
Mooring Lines ◽  
Hull Design ◽  
Truss Spar ◽  
Internal Mechanism ◽  
Double Hull

The collision mechanisms of spar platform haven’t caused so much attention as that of ships in the past, for the short of this kind of collision accidents reported. But this does not mean the impossibility of the collision accident in the future. The research on external mechanism and internal mechanism for a ship colliding with a spar platform is introduced in this paper. A model test is designed to study the external mechanism. The collision scenario is described as a ship colliding with a spar platform moored in 1500 meters water depth. The specifics of the spar’s motions and the tension forces of the mooring lines are gathered, to find the hydrodynamic characteristics in the collision scenario. It is found that the maximal displacements and the maximal pitch angles of the spar platform, and the maximal tension forces of mooring lines are all linearly proportional to the initial velocity of the striking ship basically. Mooring lines play elastic roles in the collision course. The internal mechanism of the ship colliding with the spar platform is achieved by numerical simulation method and the software used is MSC.DYTRAN. A Truss-Spar is taken as the object and a double hull structural design is adopted in the part of hard tank near water surface. The curves of collision characters and the structural damage are obtained. The crashworthiness of the double hull design is verified, through the numerical simulation results.

scholarly journals Investigation on the Structural Damage of a Double-Hull Ship, Part I – Ship Collision

2017 ◽  
Vol 5 ◽  
pp. 935-942 ◽  
Author(s):  
Aditya Rio Prabowo ◽  
Seung Jun Baek ◽  
Jung Hoon Byeon ◽  
Dong Myung Bae ◽  
Joung Hyung Cho ◽  
...  
Keyword(s):  
Structural Damage ◽  
Ship Collision ◽  
Double Hull

scholarly journals Numerical modeling of progressive failure and its implications for spreads in sensitive clays

2013 ◽  
Vol 50 (9) ◽  
pp. 961-978 ◽  
Author(s):  
Ariane Locat ◽  
Hans Petter Jostad ◽  
Serge Leroueil
Keyword(s):  
Progressive Failure ◽  
Limit Equilibrium ◽  
Pressure Ratio ◽  
Earth Pressure ◽  
High Sensitivity ◽  
Failure Surface ◽  
Soil Mass ◽  
Initiation And Propagation ◽  
Failure Propagation ◽  
Steep Slopes

Spreads are a type of large landslide occurring in sensitive clays. Stability analyses using the limit equilibrium method give factors of safety that are too large and are therefore not applicable to this type of landslide. The progressive failure mechanism is believed to explain the initiation and propagation of the failure surface and the dislocation of the soil mass in horsts and grabens, typical of spreads. A numerical method is presented to identify the parameters influencing progressive failure and to validate the application of this mechanism to spreads. The method evaluates the stresses acting in the slope before failure and models the initiation and propagation of the progressive failure. It is demonstrated that high, steep slopes, with a large earth pressure ratio at rest, are more susceptible to progressive failure and the failure surface propagates over a large distance. Failure is more likely to occur when soil with high brittleness is involved. Soil with low strength at large deformation induces failure propagation over a larger distance. Eastern Canadian clays can exhibit high sensitivity and large brittleness during shear and are susceptible to progressive failure, which explains the occurrence of spreads in these soils.

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