• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.2
• /
• pp.217-226
• /
• 2018

Since the sides of a vehicle are designed asymmetrically unlike its front or rear, the degree of deformation of the car body greatly differs depending on the site of collision if a broadside collision takes place. When elastic deformation and plastic deformation occur in the car body occur due to a collision, the kinetic energy is absorbed into the body, and the momentum decreases. Generally, an analysis of traffic accidents analyzes the vehicle's behavior after a collision by the law of momentum conservation and corrects the error of the amount of energy absorption due to the deformation of the car body, applying a restitution coefficient. This study interpreted a finite element vehicle model applying the structure of the car body and the material properties of each part with LS-DYNA, analyzed the result and drew the restitution coefficient and the depth of penetration according to the contact area of the vehicle in a broadside collision between an SUV and a passenger car. When the finally calculated restitution coefficient and depth of penetration were applied to the examples of the actual traffic accidents, there was an effect on the improvement of the error in the result. It was found that when the initial input value, drawn using the finite element analysis model, it had a higher reliability of the interpretation than that of the existing analysis techniques.

• Journal of the Society of Naval Architects of Korea
• /
• v.55 no.2
• /
• pp.144-152
• /
• 2018

This study aims to establish a mathematical formula to provide rapid and safety estimation of the damaged double hull tankers under ship-ship collision. Difference in heights between the striking and struck ships 'h' and penetration depth 'x' were considered as the main parameters. In ship-ship interaction, Large oil tankers are selected as target struck vessels, and they are struck by Very Large Crude-Oil Carrier (VLCC) class oil tanker. The residual strength of damaged ship at several locations and collision scenarios were carried out using Intelligent Supersize Finite Element Method (ISFEM) which considers the progressive collapse behavior of ship hulls strength. Based on these results, satisfactory was achieved and empirical formula was successfully established using the regression analysis method by deploying the height difference 'h' and penetration depth 'x' as the observed parameters.

• Journal of the Korean Institute of Gas
• /
• v.16 no.2
• /
• pp.1-8
• /
• 2012

According to the last 5 year statistics of KGS, there occurred 22 under ground gas pipe accidents per year in Korea. And about 5 accidents per year were caused from the third party digging. IT recognition technique could reduce such underground gas accidents. Among IT recognition technique, RFID is most poplar. In the air, RFID were applied to various fields including the distribution industry, but underground condition, the research and application cases of RFID were little This research was undertaken to see the applicability of RFID to underground gas pipe safety. By use of 900 MHz RFID reader and commercial metal tag, the stable recognition distance was measured in the similar underground condition of LNG pipe. Stable recognition depth of RFID tag were measured to be 50, 45, 25 cm in the medium of soil, 5 cm-thick-concrete+soil, and water respectively. The measured distances were considered to be the meaningful distance to prevent the gas pipe accidents Also the efficient ways to input the required gas pipe data to the 24 byte metal tag were proposed. Application of RFID to underground LNG supply system will not only reduce the gas accidents due to third party digging but also improve the gas line maintenance efficiency.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.59 no.4
• /
• pp.336-343
• /
• 2023

The aging fishery training vessels from the past have mostly been decommissioned, and many universities are introducing state-of-the-art large fishery training vessels. The purpose of these training vessels is to train marine professionals and above all, safety to prevent marine accidents should be of utmost priority as many students embark on the vessel. This study estimated the impact of the hydrodynamic interaction forces acting on the model vessel (fishery training vessel) from the bank when the vessel pass near the semi-circle bank wall in various conditions through the numerical calculation, especially concerning maneuvering motions of the vessel. For estimation, variables were mainly set as the size of the semi-circle shape, the lateral distance between the bank and the model vessel, and the depth near the bank. As a result, it was estimated that, in order for the model vessel to safely pass the semi-circle bank wall at a speed of 4 knots, the water depth to the vessel draft ratio should be 1.5 or more (approximately 8 m of water depth), and the lateral distance from the semi-circle bank wall should be 0.4 times the model vessel's length (L_pp) or more (a distance of 34 m or more). Under these conditions, it was expected that the model vessel would pass without significantly being affected by the bank wall.

• Journal of Korean Society of Transportation
• /
• v.30 no.6
• /
• pp.37-46
• /
• 2012

The number of traffic accidents caused by elderly drivers over the age of 65 has surged over the past ten years from 37,000 to 274,000 cases. The proportion of elderly drivers' accidents has jumped 3.1 times from 1.2% to 3.7% out of all traffic accidents, and traffic safety organizations are pursuing diverse measures to address the situation. Above all, connecting safety measures with an in-depth research on behavioral and physical characteristics of elderly drivers will prove vital. This study conducted an empirical research linking the driving characteristics and traffic accidents by elderly drivers based on the Driving Aptitude Test items and traffic accident data, which enabled the measurement of behavioral characteristics of elderly drivers. In developing the Influence Model, we applied the zero-inflated Poisson (ZIP) regression model and selected an accident prediction model based on the Bayesian Influence in regards to the ZIP regression model and the zero-inflated negative binomial (ZINB) regression model. According to the results of the AAE analysis, the ZIP regression model was more appropriate and it was found that three variables? prediction of velocity, diversion, and cognitive ability? had a relation of influence with traffic accidents caused by elderly drivers.

• Journal of Korean Society on Water Environment
• /
• v.22 no.6
• /
• pp.1144-1150
• /
• 2006

Recently, as water pollution accidents in rivers have increased, there is an increased interest in water quality forecast with accurate simulation. QUAL2E model, widely used for water quality analysis, uses the same hydraulic characteristics, such as depth and velocity, in a reach. The flow of the river is changed by various hydraulic constructions or by topography in a real river channel. In this study, a hydraulic connection module is developed to consider flow variations of river channels in QUAL2E model. The module uses the simulations results of non-uniform flow of a 1-D hydraulic model such as DWOPER or HEC-RAS. The improved QUAL2E model with this module was applied to a downstream section of Paldang Dam on the Han River. The results show the variation of water quality very well in a reach where flowing vary abruptly, like the Jamsil submerged weir.

• Fire Science and Engineering
• /
• v.15 no.4
• /
• pp.64-70
• /
• 2001

This study suggests fire, explosion safety assessment items and risk assessment technique for underground shopping malls by extracting dangerous elements in the management stage through examination of related accidents, documents and present conditions. This will also suggest importance of seven items to be key indices for a counterplan by classifying characteristics and trends of the large scale, depth and complexity of underground shopping malls.

• Journal of the Korea Safety Management & Science
• /
• v.9 no.6
• /
• pp.31-38
• /
• 2007

The construction industry by its nature retains higher level of danger where the smallest of error may lead to a major catastrophe endangering many workers and public safety as well as provoke social criticism. With the aid of quantitative statistical data on safety-related calamity analyzed till this day, this paper handled in depth the analysis of diseases other than the accidents, and selected new variable indexes that influence the indirect sections of calamity that are mostly concealed and incorporated them in a new model. For the factor selection of new calamity evaluation model, FRAT(Frequency, Recency, Amount, Type of merchandise/service)technique of customer-related management in marketing was applied, and as for the significance of each factor in the weight selection of variables. Consequently, considering the graveness of the FRAT itself through safety management experts, the related researches must be expanded.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1995.10a
• /
• pp.234-241
• /
• 1995

Offshore structures are exposed to higher probability of collision with ship because of their limited mobility. In general, the consequence of the collision is reported to be relatively small and it is desirable to consider minor collisions in the design stage. It is important to have a comprehensive understanding of the dynamic responses of a tubular, their main member, under collision to design offshore structure against possible accidents. It is needed to estimate the probable extent of damage of a tubular, depth of dent, affected by the time history of impact load in ender to design a tubular strong enough for collision. In this paper, dynamic behaviors of a tubular due to the lateral impact are investigated through the numerical simulations with hydrocode DYNA3D, a three dimensional elasto-plastic large deformation impact contact problem analyzing program.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2001.05a
• /
• pp.119-126
• /
• 2001

The potential pollution problems resulting from tanker collision necessitate the requirement for an effective structural design and the development of relevant safety regulation. During a few decades, the great effort has been made by International Maritime Organization and the Administration, etc, to reduce oil spillage from collision accidents. However there is still a need for investigation in the light of structural evaluation method for the experiments and rational analysis, and design development for an operational purpose of ships. This study is aimed at investigating a complicated structural response of bow structures of oil carriers for assessing the energy dissipation and crushing mechanics of striking vessel through a methodology of the numerical analysts for the various models and its design changes. Through this study an optimal bow construction absorbing great portion of kinetic energy in the least penetration depth prior to reach to the cargo area and an effective location of collision bulkhead are investigated. In order to obtain a rational results in this study, three stages of response analysis procedures are performed as follows; 1). 16 simplified ship models are used to investigate the structural response against bow collision with variation of primary and secondary members. Mass and speed are also varied in two conditions. 2). 21 models conisted of 5 size of full scaled oil carriers are used to perform the collision simulation with the various sizes and deadweight delivered in a recent which are complied with SOLAS and MARPOL. 3). 36 models of 100k oil carrier are used to investigate the structural response and its influence to the collision bulkhead against bow collision in variation with location of collision bulkhead, primary mombers, framing system and colliding conditions, etc.