• International Journal of Highway Engineering
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• v.12 no.4
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• pp.197-202
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• 2010

Post release mechanism is generally used to reduce the severity of the occupant of an errant vehicle impacting a roadside posts. The 820kg-50km/h head-on impact simulations were made using LS-DYNA program for the posts of 101.6mm Dia(t=4.0mm) with and without clip-type release mechanism. The simulation result was compared with impact test result to enhance the credibility of simulation model. The study shows that the high impact severity (THIV, PHD) and excessive deformation threatens the safety of the occupant when a car impacts a rigidly connected posts, while a post with clip-type slip base reduce the impact severity to a safe level.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.98-99
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• 2016

The aim of study is to develop a dual driven ship berthing/deberthing system with $360^{\circ}$ steerability. A large ship used bow thruster, side thruster and pod propulsor etc. when approaching to a pier. But as marine leisure boats become large-scaled, the number of accidents is recently increasing what caused a ship to crash into a ship and a ship to crash into mooring facilities during berthing/deberthing on a marina. To solve the problem, the control responsiveness of a joystick connected with two motors and a propeller was checked and torque was increased by the electromagnetic design of magnetic gear. A sea trial test was carried out to investigate a performance of the developed system in the real sea.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.417-428
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part III, the local damage of the rigid components of aircraft, e.g., engine and landing gear, impacting the steel concrete (SC) structures of NPP containment is mainly discussed. Two typical SC target panels with the thicknesses of 40 mm and 100 mm, as well as the steel cylindrical projectile with a mass of 2.15 kg and a diameter of 80 mm are fabricated. By using a large-caliber air gas gun, both the projectile penetration and perforation test are conducted, in which the striking velocities were ranged from 96 m/s to 157 m/s. The bulging velocity and the maximal deflection of rear steel plate, as well as penetration depth of projectile are derived, and the local deformation and failure modes of SC panels are assessed experimentally. Then, the commercial finite element program LS-DYNA is utilized to perform the numerical simulations, by comparisons with the experimental and simulated projectile impact process and SC panel damage, the numerical algorithm, constitutive models and the corresponding parameters are verified. The present work can provide helpful references for the evaluation of the local impact resistance of NPP buildings against the aircraft engine.

• Journal of Korean Society of Transportation
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• v.29 no.2
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• pp.59-67
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• 2011

To minimize the degree of damage in the SMART highway's punctuality and safety occurred from the car-barrier collisions, the impact conditions for longitudinal barriers in SMART highway was determined to be significantly larger than the existing maximum impact conditions. Results from computer simulation runs show that the existing domestic highest-performance roadside barrier did not satisfy the suggested impact conditions. The newly developed N-class barrier designed with computer simulation model and verified by full-scale crash tests has satisfied the SMART highway impact conditions in terms of occupant safety indexes and structural adequacy.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.201-212
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• 2017

PURPOSES : The objective of this study is to identify the characteristics affecting traffic accidents that have occurred in 564 industrial complexes nationwide from 2011 to 2015. METHODS : The traffic accidents were specified using various factors such as industrial complex type (national VS. general), industrial complex degradation (old VS. non-old), location of complex (capital VS. non-capital), and traffic law violation (speeding, signal violation, and median invasion). The average number of crashes and accident ratio (fatal, severe, and both) in terms of characteristics of industrial complexes were calculated. With a sample of crashes of the industrial complexes for 5 years, statistical significances were tested to analyze and compare the differences based on industrial complex and traffic law characteristics using parametric and non-parametric methods. RESULTS : From statistical results, it is observed that the crash frequency occurring in old industrial complexes is three times higher than that in non-old industrial complexes. Old industrial complexes located in a capital area, old national industrial complexes, and old general industrial complexes are considerably related to higher crash frequency, but the fatal accident ratio appeared to have no statistical difference across industrial complex characteristics. Severe crashes are more likely to occur in non-old industrial complexes on an average. CONCLUSIONS : It is necessary to eliminate potential threats to roads and traffic in the same manner as illegal parking in industrial complexes through the restoration of old industrial complexes. To improve the efficiency of road infrastructure, efforts should be made to improve traffic safety in accordance with industrial characteristics such as planning and operation of relevant local government programs.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.432-438
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• 2016

Whiplash injuries in low-speed rear-end collisions are the most common injuries and has been a social issue in insurance industry, such as excessive medical claim costs along with exaggerated injuries of victims and treatments from hospitals. According to the Korea Insurance Development Institute reports, the number of claims by rear-end collision was approximately 703,000, which accounts for 53.6 % of the total car-to-car collisions in 2014. Part of the neck injury claims in the Korea car insurance was approximately 28.3 %. Furthermore, approximately 98.4% of the injured persons in rear-end collisions sustained minor injuries under AIS2. In order to improve this situation as well as find out the severity of neck injuries from rear-end collision, the Korea Automobile Insurance Repair Research and Training Center conducted car-to-car rear-end crash tests that striking vehicles(SUV) collided into different sizes of struck-vehicles(small, middle, and large sedan) at the impact speeds of 8 km/h ~ 16 km/h. In order to analyze the whiplash injury, the BioRID-II was seated in each struck-vehicles, and the neck injury criteria(NIC), head contact time, maximum vehicle accelerations, and mean vehicle accelerations were calculated from values from the accelerations of the dummy and the struck-vehicles.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.55-62
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• 2015

An importance of infrastructures' protection against crash or blast loading has been an emerging issue as structures are becoming much bigger and population densities in downtown are growing up. However, there exists no such a standard to evaluate the protection performance of construction material itself. Prior to building standards for protection assessment techniques, this study performed gas-gun propelled projectile impact tests with series of contact-type monitoring systems to investigate the applicability of each sensing type. Through the impact tests, failure modes and protection performances of both normal concrete and UHPC (Ultra High Performance Concrete) reinforced by steel fibers were also evaluated. The results showed that LVDT could be applicable for the impact test among contact-type sensors and UHPC with fibers had a remarkable potential to improve protection against impact loading.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.345-351
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• 2003

Due to increasing legal and market demands for safety in the automotive design process, the design of integrated seat is important more and mote because it should satisfy the conflict between stronger and lower weight for safety and environmental demands. In this study for crash simulations, the numerical simulations have been carried out using the explicit finite element program LS-Dyna according to the FMVSS 210 standard for safety test of seat. Since crash simulations are very time-consuming and a series of simulations that does not lead to a better result is very costly, the optimization method must be both efficient and reliable. As a result of that, statistical approaches such as design of experiments and response surface model have been successfully implemented to reduce time-consuming LS-Dyna simulations and optimize the safety and environmental demands together with nonlinear optimization algorithm. Design of experiments is used lot exploring the design space of maximum displacement and total weight and for building response surface models in order to minimize the maximum displacement and total weight of integrated seat.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.84-92
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• 2005

This paper is concerned with optimum design of a center-pillar assembly induced by the high-speed side impact of the vehicle. In order to simulate deformation behavior of the center-pillar assembly, simplified finite element model of the center-pillar and a moving deformable barrier are developed based on results of the crash analysis of a full vehicle model. In optimization of the deformation shape of the center-pillar, S-shaped deformation is targeted to guarantee reduction of the injury level of a driver dummy in the crash test. Tailor-welded blanks are adopted in the simplified center-pillar model to control the deformation shape of the center-pillar assembly. The thickness of each part which constitutes the simplified model is selected as a design parameter. The thickness of parts which have significant effect on the deformation mechanism are selected as design parameters with sensitivity analysis based on the design of experiment technique. The objective function is constructed so as to minimize the weight and lead to an S-mode deformation shape. The result shows that the simplified model can be utilized effectively for optimum design of the center-pillar members with remarkable saving of computing time.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.215-226
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• 2007

To verify the performance of roadside barriers, occupant risk indices are calculated from acceleration and angular velocity data of vehicle crash tests. The occupant risk indices to be computed include THIV(Theoretical Head Impact Velocity), PHD(Post-impact Head Deceleration), ASI(Acceleration Severity Index), OIV(Occupant Impact Velocity) and ORA(Occupant Ridedown Acceleration). There is a confusion due to different values of occupant risk indices produced for the same test data because various computational procedures and data processing methods can be applied to compute them. To slove this problem the effects of various numerical procedures and data processing methods on occupant risk indices were investigated. If the sampling rate specified in the guidelines is used for full-scale vehicle crash tests, an interpolation of impact time and numerical integration methods do not result in an appreciable change of THIV and OIV. The way to determine 10msec moving average for PHD and zero offset of data processing should be specified in the guidelines because 10msec moving average and zero offset methods have a significant influence on occupant risk indices.