• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.326-330
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• 2007

Bumper back beam is one of the essential structural components of front-end module. It should be designed to withstand a minor bump in low-speed collision, 2.5 mph crash test for example. And weight reduction is always important problem in the design of almost all the parts in car for energy saving. So, the key issues in shape design of a bumper are weight reduction and the performance in 2.5mph crash test. In this study, a light weight and high performance bumper back beam model was developed using analytical approach based on mechanics and FE simulation together.

• Transactions of Materials Processing
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• v.24 no.5
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• pp.354-360
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• 2015

AHSS (Advanced High Strength Steels) has been increasingly employed by global automotive OEMs in order to satisfy strengthened regulations and reduce weight for fuel efficiency. Hot stamping using boron steels in AHSS increases not only formability but also strength. The typical hot-stamped automotive part is the center pillar that is critical for vehicle side impact. However, the hot-stamped part can be risky for the passenger safety caused by brittle fracture under a vehicle collision. The high power diode laser is suitable for the heat treatment giving AHSS increased elongation that prevents brittle fracture in car crash. Therefore, local softening by laser heat treatment for energy absorption area on the hot-stamped part improves crash-worthiness.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1236-1242
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• 2010

Currently in design and manufacturing of railway train overseas markets, criteria for a collision condition between vehicles is noted in design specification. In the event of a train crash, it can be verified by crashworthiness analysis or an actual crash test for car's performance to keep the safety of passengers and to minimize the effect of damaged for vehicles. In this paper, it is described for carbody structure to meet the allowable condition in collision analysis through improvement of shape, position and arrangement for carbody frame. This report describes the shape of end frame for carbody structure and the results of analysis applied to actual cases for overseas.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.7-15
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• 2008

New Car Assessment Program(NCAP) provides consumers with vehicle safety information, primarily front and side crash rating results, and more recently rollover ratings, to aid consumers in their vehicle purchase decisions. NCAP is a system to improve driver and passenger safety by providing market incentives for vehicle manufacturers to voluntarily design their vehicles to better protect drivers and passengers in a crash and be less susceptible to rollover, rather than by regulatory directives. NCAP have been performed since 1999 in Korea by the government in order to reduce fatalities and injuries caused by traffic accidents. Although as the number of vehicles models increases, more vehicle models are required to be test and NCAP is evaluated as a valuable system for vehicle safety, the expansion of the system is slow. It looks like that the benefit of NCAP quantitatively was not verified. In this study, based on the idea that the benefit of the NCAP is defined as the decrease of traffic accident severity by improving vehicle safety, a methodology to analyze the effectiveness of NCAP quantitatively in terms of traffic safety was developed. According to the developed methodology, the reduced numbers of fatalities and injuries were 1.51 and 466 in 2005.

• Fire Science and Engineering
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• v.25 no.5
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• pp.119-127
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• 2011

Because of most notably the increase in vehicular traffic in Korea, as measured by highway transport usage, relief is being sought by expanding the construction of highways after 1970s'. These highways have opened up over 70 % of the mountainous areas in Korea's country side which includes the construction of tunnels. Currently there are 607 tunnels installed that are being maintained and by 2015, under the next medium-term plan, Korea will build an additional 440 tunnels. In addition, the use of 1,000m double-pole tunnels is expected to increase significantly in 256 locations. There is no doubt that these tunnels will relieve traffic congestion and aid improved communications, but halfclosed underground highway tunnels in particular are required to reduce tunnel fires caused by poor vehicle maintenance, and other factors such as speeding motorists that increase the number of vehicular accidents. Double-pole tunnels in 1,000m length over require vehicle drivers to be more cautious in terms of the continuous speed limit, judged by how devastating most of car-crash fires within these tunnels can be. In order to prevent these disasters, a full-length tunnel speed enforcement system should be considered mandatorily in legal clauses.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.32-38
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• 2020

This study examined the problems of existing vehicles to propose alternatives to improve the crashworthiness of railway freight cars through collision acceleration analysis using a one-dimensional collision analysis method. A collision scenario of railway shunting and crash accidents was selected from the collision accident cases and international standards. A one-dimensional collision simulation using LS-DYNA was performed according to those scenarios. As a result, the acceleration level of the freight wagon was calculated to be under 2g and was predicted to meet the EN 12663 standard in the shunting situation. On the other hand, the result of crash simulation with an impact velocity between 10 and 15 km/h revealed the shock absorber capacity of the railway coupler to be insufficient in a crash situation, resulting in increased acceleration, and carbody deformation could be predicted. As a method of improving the crashworthiness, a deformation tube-type energy absorber was applied to the coupler system, and collision analysis was performed again with new energy absorption strategy. Overall, the simulation showed that the acceleration level was decreased by 12% of the conventional freight-car energy absorption system.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.97-104
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• 2008

Many atypical structures on the roadside are exposed to traffics unshielded posing great danger. One way to shield an atypical structure to secure the occupant safety is to stack energy absorbing material modules in front of the structure. This paper presents the analysis method of module type crash cushion made of EPS blocks using simple energy balance of the car and crash cushion and numerical examples for 0.9ton-500km/h, 0.9ton-60km/h and 0.9ton-70km/h impact are presented. This method gives simple estimation of maximum acceleration, time of crash, whether or not the vehicle stops completely before whole cushion is being crushed. However, since the acceleration and velocity data from the analysis is so crudely spaced that calculation of safety indices such is RA and OIV is not possible. Problem is overcome by using data interpolation. The spline and linear interpolation is introduce and safety analysis is made and the results are compared.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1577-1584
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• 2002

This paper develops a finite element model for studying the occupant behavior and injury cofficients of a large-sized cab-over type truck. Since it does not have a room to absorb collision energy and deformation in front of the passenger compartment the deformation is directly transmitted to the passenger compartment. Moreover, since its steering column is attached on the frame, severe deformation of the frame directly affects on the steering wheel's movement. Therefore, if the occupant behavior and injury coefficients analysis is performed using a finite element model developed based on a sled test, it is very difficult to expect acquiring satisfactory results. Thus, the finite element model developing in this paper is based on the frontal crash test in order to overcome the inherent problems of the sled test based model commonly used in the passenger car. The occupant behavior and injury coefficients analysis is performed using PAM-CRASH installed in super-computer SP2. In order to validate the reliability of the developed finite element model, a frontal crash test is carried out according to a test method used fur developing truck occupant's secondary safety system in european community and japan. That is, test vehicle's collision direction is vertical to the rigid barrier and collision velocity is 45kph. Thus, measured vehicle pulses at the lower parts of the left and right B-pilla., dummy chest and head deceleration profiles, HIC(head injury criterial) and CA(chest acceleration) values, and dummy behavior from the frontal crash test are compared to the analysis results to validate reliability of the developed model.

• 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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.40-44
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• 1998

In this study, the subframe of passenger car is developed by typical analysis and carsh simulations. According this results, energy absorption and barrier froce is very important to control passenger safety and deformation shape. For that purpose, it is most effective to absorb energy more tailor welded blanks(TWB) subframe than non-TWB. The subframe with TWB is simulated, in which reduced stamping parts, weight reduction and cost down.