• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.6
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• pp.365-370
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• 2023

This paper presents a particle-structure collision model for topology optimization, which requires sensitivity analysis. Therefore, a new model that incorporates sensitivity analysis is needed. The proposed particle-structure collision model conducts sensitivity analysis for topology optimization. To evaluate the accuracy of the proposed model, it was applied to a simplified one-dimensional collision problem. Optimization of the final positions of particles using topology optimization through this model confirmed the suitability of the proposed approach. These results demonstrate that it is possible to consider particle-structure collision in topology optimization.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.151-154
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• 2007

THE DOMESTIC AND FOREIGN OF THE COUNTRY RAILROAD ACCIDENT ANALYSIS IT LED FROM THE PAPER WHICH IT SEES AND IT ANALYZED A TRAIN COLLISION/DERAILED ACCIDENT RISK FIXED QUANTITY. THE TRAIN ACCIDENT OCCURS DIRECT AND LATENT DAMAGE. IT CLASSIFIES THE ACCIDENT WHICH 5 YEAR FOR OCCURS RECENTLY DOMESTIC AND FOREIGN OF THE COUNTRY WITH A TYPE FROM THE RESEARCH WHICH IT SEES. IT TRIED TO ANALYZE THE DAMAGE SIZE AGAINST A TRAIN COLLISION/DERAILED ACCIDENT WITH DANGEROUS QUOTIENT.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.13-20
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• 2013

In this paper, a collision accident of a container/Ro-Ro ship was numerically analyzed. A container trailer collided with a longitudinal bulkhead of the ship in the accident, which constituted a longitudinal wall of a heavy fuel oil tank. Due to the accident, the bulkhead plate was ruptured and the heavy fuel oil spilled out of the tank. The detailed information regarding the collision velocity and the mass of the trailer was not provided. Therefore, several collision accident scenarios were constructed based upon the arrangement of the ramp way. Each collision accident scenario was analyzed to predict the extents of damage using a commercial numerical package, ABAQUS. Based on the analysis results it is proposed how to minimize the extents of damage. Through the investigations performed in this study it was found that the understandings of various damages due to collision accidents and the developments of structural design guidance against collision are necessary for the betterment of Container/RO-RO ships' performance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.71-76
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• 2004

To deal with ship collision or grounding, double hull structure has been applied to ships carrying dangerous cargoes. Studies about ability of double hull structure to absorb collision energy and determining fracture state are still under researching. In this study, commercial analysis code, LS-DYNA3D, is used to analyze collision strength of ships in various scenarios. 46K Chemical／Product Carrier is used as analysis subject ship. Study about Energy-Indentation and Force-Indentation is conducted under conditions that weight and collision velocity are changed. Results of this study are very helpful to make mechanism of collision accident clear and to supply useful information about collision strength criteria.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.607-615
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• 2005

In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of the bridge. Method I in AASHTO LRFD bridge design specifications is a semi-deterministic analysis procedure for determining the design vessel. Method ll which is a more complicated probability based analysis procedure is used to select the design vessel for collision impact. The AF allocation by weights seems to be more reasonable than the pylon concentration allocation method because AF allocation by weights takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. Therefore more researches on the allocation model of AF and the selection of design vessel are required.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.724-729
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• 2016

This case study carried out a rear-end collision accident analysis and physical simulation of an SUV and passenger car. The speed of the SUV by physical analysis is 71 ~ 87 km/h, while the speed of the passenger car is 6 ~ 22 km/h. Simulation results showed the optimal speed conditions for the SUV was 71 km/h, and 7 km/h for the passenger car. Simulations can be verified for the collision analysis. The findings of this study are expected to increase the reliability of accident reconstructions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.4
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• pp.213-220
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• 2023

This paper presents a model simulating the folding process and collision dynamics of "ddakji", a traditional Korean game played using paper tiles (which are also referred to as ddakji). The model uses two A4 sheets as the base materials for ddakji. The folding process involves a series of boundary conditions that transform the wing part of the paper structure into a twisted configuration. A rigid plate boundary condition is also adopted for squeezing, establishing the shape and stress state of the game-ready ddakji through dynamic relaxation analysis. The gaming process analysis involves a forced displacement of the striking ddakji to a predetermined collision position. Collision analysis then follows at a given speed, with the objective of overturning the struck ddakji--a winning condition. A genetic algorithm-based optimization analysis identifies the optimal collision conditions that result in the overturning of the struck ddakji. For efficiency, the collision analysis is divided into two stages, with the second stage carried out only if the first stage predicts a possible overturn. The fitness function for the genetic algorithm during the first stage is the direction cosine of the struck ddakji, whereas in the second stage, it is the inverse of the speed, thus targeting the lowest overall collision speed. Consequently, this analysis provides optimal collision conditions for various compression thicknesses.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.199-206
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• 2011

In Korea, the current design codes for the bridge vessel collision load are based on AASHTO LRFD code which derived from the mean collision forces of the Woisin's test. To estimate the conservativeness of the code, in this study, the mean forces of head on collisions were evaluated from the mass-acceleration relationship of vessel and the deformation-kinetic energy relationship of bow those obtained from the series of nonlinear finite element analysis, and the mean forces were compared to that in AASHTO design code. As results, the variations of the mean forces versus the sizes of vessels were represented similar tendency, even those of the code are very conservative. However, the variations of mean collision force versus those of collision speeds were dominated by the plastic deformation of bow and it was differ from those of the code that have linear relationship with the collision speeds.

• Journal of Auto-vehicle Safety Association
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• v.15 no.4
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• pp.88-94
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• 2023

The seating postures of passengers in the automated driving vehicle are possible in atypical forms such as rear-facing and lying down. It is necessary to improve devices such as airbags and seat belts to protect occupants from injury in accidents of the automated driving vehicle, and collision safety evaluation tests must be newly developed. The purpose of this study is to define representative types of head-on collision accidents to develop collision standards for autonomous vehicles that take into account changes in driving behavior and occupants' postures. 150 frontal collision cases remained by filtering (accident videos, images, AIS 2+, passenger car, etc…) and random sampling from approximately 320,000 accidents claimed by a major insurance company over the past 5 years. The most frequent accident type is a head-on collision between a vehicle going straight and a vehicle turning left from the opposite side, accounting for 54.7% of all accidents, and most of these accidents occur in permissive left turns. The next most common frontal collision is the center-lane violation by drowsy driving and careless driving, accounting for 21.3% of the total. For the two types above, data such as vehicle speed, contact point/area, and PDOF at the moment of impact are obtained through accident reconstruction using PC-Crash. As a result, two types of autonomous vehicle crash safety test scenarios are proposed: (1) a frontal oblique collision test based on the accident types between a straight vehicle and a left-turning vehicle, and (2) a small overlap collision test based on the head-on accidents of center-lane violation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.127-133
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• 2009

The suspension bridge between Myodo and Gwangyang is located in the main navigation channel to Gwangyang Harbor. So, there is need for the collision protection against large vessels. In this paper, the method of risk analysis and non-linear numerical analysis are conducted to consider the ship collision effects. The results of risk analysis, the annual frequency of collapse is more than the acceptable frequency 0.0001. Therefore, as a ship collision protection, island protection with concrete block quay wall is planned. The ship collision force on the pylon is less than the lateral capacity of pylon from the nonlinear numerical analysis.