Recently, due to the rapid increase in vehicle accidents, research on improving seat belts and restraint system are being actively on going to solve the problems in vehicle for passengers. The characteristics of lap belt load and pelvic displacement were simulated through MADYMO program using Hybrid III 50th percentile male dummy to analyze the submarining by changing the collision speed and seat back angle by applying the forward collision pulse form accident scenario. As a result, the submarining occurred when the seat-back angle was 60° or higher at the collision speed of 50km/h or higher. Lastly, using the characteristics of the lap belt load and pelvic displacement when the anti-submarining belt (ANSB) system adapted, the pelvic displacement was reduced as well as submarining.

ADAS(Advanced Driver Assistance System) for automobiles is being developed based on evaluation protocols. Radars, LiDars, and cameras are also being developed by many auto parts suppliers including automobile manufacturer, for automobile safety, but protocols following weather condition are still weak. In South Korea, typhoons that occur in summer in four seasons are the most damaging to property. Therefore, the research is needed based on the virtual environmental conditions of typhoons such as precipitation, wind speed, and temperature. In this study, it was derived that the average error rate for each typhoons condition such as SNR (Signal to Noise Ratio) and RCS (Radar Cross Section) is different by analyzing the effect of typhoons occurring in South Korea on radar according to virtual environmental conditions. It is expected that radar’s analysis from typhoon conditions data can be used to develop radar sensors.

In this study, a mixed resin containing Bis-GMA was developed to produce a light-emitting sign using quantum dots. As a result of measuring the viscosity, color coordinates change, and luminance of the mixed resin, the following conclusions were obtained. The viscosity of the mixed resin decreased as the content of the diluent increased, and viscosity values ​​ranged from 3,627 to 1,349cps showed as a result. The viscosity of the mixed resin decreased as the temperature increased, and the viscosity showed a value of 5,156 to 1,132cps. For the optical properties of InP/GaP/ZnSe/ZnS quantum dots, the absolute quantum efficiency was 91% at 522nm and 90% at 618nm when the gallium was 0.01%. The luminance of the light-emitting sign using the resin mixed with quantum dots was showed 142.6cd/m2 in white and 104.2cd/m2 in the red region.

In this study, the Euro NCAP-based AEB system evaluation simulation was conducted by applying the calculated corrected TTC by road condition estimation of scenarios (CPFA, CPNC, CPLA) of the V2P situation scenario using PC-Crash, a program used for traffic accident analysis. The scenario was evaluated in consideration of the two road conditions. the low-speed conditions among every scenarios avoided collision, but in the medium and high-speed conditions has been collided with pedestrian. It was confirmed that the time point at recognizing pedestrian was lower than set TTC at which AEB system was operated, even though the AEB was operated immediately, a collision occurred due to insufficient braking distance. As in this study, if studies such as V2V, V2P, and V2B considering road friction are actively conducted, it is expected to be useful data for automobile accident prevention and accident analysis.

In this study, the AEB system evaluation simulation was conducted by applying a corrected TTC from 0s to 3s obtained by estimating the road-friction factor and slope applying two scenarios(CCRs and CCRm) that may occur in V2V situation using PC-CrashⓇ, a program used for traffic accident analysis. As a result of two scenarios : At 0.8 of road-friction factor and 0° slope which adapted default model of TTC had longer braking distance so that it crashed. At 0.2 of road-friction factor with corrected TTC slidingly crashed due to slope and braking condition. CCRs and CCRm scenario showed that the maximum slipped distance of the collision avoidance situation was 31.7m, 87.7m. And the collision speed was 35.7km/h at 50km/h and 66.1km/h at 80km/h.

The event recording devices such as EDR and DTG have recently been developed and installed in automobiles. The reliability of EDR application is being conducted in many previous studies, but with the development and development of autonomous vehicles, it is necessary to study the reliability of EDR and DTG application results for programs that can analyze autonomous driving. Therefore, in this study, the analysis was carried out in a way to secure the reliability of the application results of EDR and DTG of Carmaker, which can analyze the traffic accident analysis program PC-Crash and autonomous driving, and secure the reliability of the Carmaker program that applied EDR in Korea and abroad. As a result of the analysis, it was found that the speed error rate gradually increased from high speed to low speed, and the maximum error speed was less than 5 km/h through the average error rate for each speed. In the future, it is thought that it can be usefully used for analysis of traffic accidents in the event of autonomous vehicle accidents.

Solar energy is being constantly studied since it can reduce green house gas by adapting cooling and heating system of domestic architecture as a clean energy source. This study confirmed the reliability of experimental apparatus with temperature measurement of each components by developing cooling and heating system which is combined with artificial solar thermal energy using halogen lamp and refrigerator, examined the heat transfer characteristics according to room internal temperature and lamp distance with the materials of emissive plate (acrylic, copper and stainless). As a result of it, We found that the room internal temperature 18℃ was finer than 21℃ and 24℃ in case of heat transfer rate according to each components. Also, copper in the material change of emissive plate was showed finer heat transfer effects than stainless because of high thermal absorptivity when lamp distance was short.

This study is carried out to analyze the velocity distribution for each location and the uniformity index according to straight distance on exit side by changing the design factors of branch pipe connected to 180° circular mixing-tee using RSM(Reynolds Stress Model) turbulence model. As the results of the flow characteristics according to hydraulic diameter, the velocity profiles in the 90° sectional area are generally similar. In the 180° section, the maximum velocity point shows Y/D=0.7~0.8 after rapid increase of the flow velocity. In the result according to the distance away from inlet, the maximum velocity point in the 90° sectional area is located in outer side of the curved pipe as the distance away from inlet increases. In the 180° sectional area, the maximum velocity point is showed in Y/D=0.7~0.8 after the rapid increase of the flow velocity regardless of the variation of branched distance. In case of inclined angle, the maximum velocity point in the 90° sectional area is located in outer side of the curved pipe as the inclined angle increases. In the 180° sectional area, the maximum velocity point is observed in Y/D=0.8 regardless of the inclined angle. In addition, the uniformity index of flow velocity shows that it is stabilizing after approximately L/D=40 away from the end of the curved pipe regardless of the flow factors in the branch pipe.

The purpose of this study is to analyze the temperature and heat resistance distribution, which is a criterion for evaluating the cooling performance, by using computer simulation of the cooling system combined with the CPU of the individual highest heat generation section, and use it as important data for the heat sink design. Using a single material of Al 6063-T5, which is an integral part of the desktop, fan and heat sink, fins and base, the analysis was carried out with various fin numbers, thicknesses, pitches and shapes of heat sinks. Ambient temperature, 25°C, heat source, 130W and cooling fan speed, 2500 rpm (50CFM) were used as boundary conditions, and heat transfer characteristics regarding temperature distribution and heat resistance were investigated using ANSYS Icepak. As a result, it has been found that as the number of fins of heat sink increases, the heat dissipation area increases to decrease heat resistance, and as the distance between each fin decreases, the ventilation resistance increases to decrease the flow intensity of the cooling air in contact with the heat dissipation area. The sunburst array also exhibits better heat transfer characteristics by obtaining a lower distribution of heat resistance with a cooling effect of about 10°C than the one-way basic array.

In this study, velocity distribution characteristics by location and uniformity according to exit straight length in a 180° mixed pipes were numerically analyzed using RSM (Reynolds Stress Model) turbulent model by changing various flow parameters such as working fluids, inlet air velocity etc. As a result of it, the working fluids characteristics was highly indicated by the viscous force difference, the maximum velocity points according to main pipe’s inlet velocity were indicated when 90° sectional location was distributed at X/D=0.5~0.6 region and 180° sectional location was distributed at Y/D=0.5 region. And the flow characteristics according to branch pipe’s inlet velocity when 90° sectional location was distributed at X/D=0.4~0.6 region and 180° sectional location was distributed at Y/D=0.5 region. Based on the results that the most stable exit straight length in flow uniformity was indicated at L/D=25~30 region, 40D is suggested as the effective measurement distance in the straight pipe downstream curved pipe of mixed pipe.

According to the automobile industry has been developing day by day, traffic accidents are increasing and the rear-end collision is the second largest of the entire collision. Due to the high social cost caused by rear-end collision, several studies are in progress at home and abroad. Previous studies have shown that neck injury caused by rear-end collisions can be prevented by seat conditions. In this study, to find the condition that reduces neck injury, change of neck injury in rear-end collision is analyzed according to headrest height, seatback angle, and seatback torque using BioRID II dummy model and passenger behavior analysis program MADYMO. Therefore, it is expected that the condition of each variable to reduce the risk of injury to the neck can be applied to the seat design, which will reduce the injury and the social cost caused by the rear-end collision.

Recently the incidence of rollover accidents has increased due to the increase of SUV, and the probability of occupant injury in rollover accidents is very high, so research is needed accordingly. In this study, PC-CRASH, which is a program used for traffic accident analysis, is used for checking rollover speed and rollover angle of each situation in case of rollover accident, and applied to design variables of LS-DYNA which is finite element analysis program, so deformation displacements of roof according to collision velocity and angle were derived. Also, it is possible to predict rollover vehicle speed by using the derived value and the measured deformation displacement of roof in actual rollover accident, and it is possible to reconstruct accident more accurately by applying to PC-Crash which is traffic accident reconstruction program, so it is thought that it can be utilized analyzing traffic accident usefully.

In this study, the CFD analysis was performed by changing the geometry of coil-tube diameter ratio, coil winding number, coil pitch, and cross section of the tube to investigate the heat flow characteristics of forced convection in a helical coil-tube heat exchanger using RSM (Reynolds Stress Model). As a result, the secondary flow was developed in the tube caused by the influence of centrifugal force. It improved the heat transfer on the outer side of the tube, but on the inner side was not performed well. And the temperature rose locally in the tube region. Also the pressure drop in the tube was proportional to the diameter ratio of the coil-tube and the inlet velocity, and it was found that pressure drop and friction factor were inversely proportional. When the coil winding number and coil pitch were increased, it affected heat transfer in the low speed range of 0.1 ~ 0.2 m/s, but did not affect the flow condition after this range.

The heat transfer characteristics of forced convection according to the geometric shapes with four rectangular blocks in a horizontal PCB channel was analyzed numerically using SST (Shear Stress Transport) turbulence model. As the boundary condition for CFD (Computational Fluid Dynamics) analysis, the inlet temperature and air velocity were respectively 300 K and 3.84 m/s and the heat flux of the block surface was 358 W/㎡. The shape factors of block were width, height, spacing and channel entrance height. As the results, the heat transfer rate was decreased as the width ratio (x/h) was increased, while it was increased as the height ratio (h/x) is increased. Also as the block spacing ratio (s/x) was increased, the heat transfer effects was not significantly affected. And as the channel entrance height ratio (H/x) was increased, the heat transfer performance was decreased.

In this study, FLUENT v.16.1 was used to investigate the compressible flow generated by the supersonic jet spewed from a high pressure tube. As the boundary condition for CFD (Computational Fluid Dynamics) analysis, the inlet temperature of air was constantly 300 K and the variation of JPR (Jet Pressure Ratio) were 5, 50, 100, 150 and the variation of tube diameter were 10, 20, 30 cm. As a result, it was confirmed that the effective range was increased as the JPR was higher, but it was confirmed that the effective range was lower than the JPR rise, and that the effective range was increased as the diameter was larger. Therefore, it is found that the tube diameter is more sensitive than the JPR among the influence factors of jet, and if the result of this study were reflected in the design of high pressure system, it will contribute to the design of the system for preventing the second accident.

In this study, analysis on the stiffness of the headrest, the stiffness of front-rear load and the torsion of cushion frame was performed using finite element method in order to investigate the properties of the stress-deformation by material characteristics according to the test requirements of FMVSS (Federal Motor Vehicle Safety Standard). The results are shown that AZ31 (Mg alloy) and A365 (Al alloy) with low modulus of elasticity and density have higher strain rate than steel in terms of stress-deformation and meet the standards for safety within 108 mm of the maximum amount of deformation. Considering it’s safety and durability, however, the selection of AZ31 for light weight seems difficult to gain the reliability because it causes an excessive deformation, and therefore it is not expected to be used for recliner where stress is concentrated and also the bracket linking rail and cushion frame.

In this study, the heat flow characteristics of natural convection was theoretically analyzed with time by changing various locations of heat trace with tube surface about enclosed circular tube by applying nominal tube diameter 90 mm of KS D 3507. Before carrying out CFD (Computational Fluid Dynamics) analysis, it is presumed that the boundary condition is the tube’s inside and outside fluid temperature of 273 °K, the tube surface heat flux according to the heat trace location of 16 W/m. The result confirmed that water of inside tube is occurred natural convection caused by density difference depending on temperature profile. Additionally, in case of heat trace location, the heat transfer and flow characteristics showed clearly that two-heat trace location =135° and 180° was more favorable distribution than one-heat trace appropriate location =135°.

This study was experimentally analyzed to search the swirl characteristics of helical intake port for the performance improvement in direct injection diesel engine. The intake port flow is important factor which has influence on the engine performance because the properties in the injected fuel depend on the combustion characteristics. In order to analyze the characteristics of swirl in the helical intake port of cylinder head, flow coefficient and swirl ratio were measured by an impulse swirl torque meter at position of 1.75 cylinder diameter for different valve lifts at the steady flow condition with intake port of the in-line and V type engine. Each intake ports were established swirl ratio 1.70, 2.13, 2.25, 2.38 and 2.43 by hand working. The results of steady flow test showed that flow coefficient and swirl intensity increased as valve lift increased, while the increase of swirl ratio according to the change of intake port geometry decreased mean flow coefficient and increased Gulf factor.

This study is experimentally to analyze the heat transfer characteristics and photographic observation of bubble generation in saturated nucleate pool boiling. The photographs were taken of water boiling from heated nickel wires. The attempts is made to explain the different nucleate boiling of water. Some of the bubbles photographed were very close to the spherical shape, while others were close to the hemispherical. Also, a number of bubble had intermediate shapes that were called oblate bubbles. At least, heat transfer regions of three and possibly four were found to exist in nucleate boiling depended upon the mode of vapor generation. The vapor structure on the surface progressed through a sequence of first discrete bubbles, then vapor columns and vapor mushrooms, and finally vapor paths, as the surface temperature was increased. These individual vapor structures or combinations of them determine the mechanism of heat transfer in the four nucleate boiling regions.

HFC-134a is currently used as a refrigerant in automotive air conditioning system replacing the ozone depleting CFC-12 refrigerant. This paper was experimentally studied on the performance characteristics of an automotive air conditioning system with variations of charging refrigerant and compressor speed. An air conditioning system was composed of laminated type evaporator, parallel flow type condenser, vane rotary type compressor, externally equalized thermostatic expansion valve and receiver drier with specifications of Hyundai Sonata Ⅱ vehicle. And the automatic measuring system of air conditioner used KTE-1000BA developed by a KT ENG Co., Ltd.. of Korea. The optimum conditions which were tested as available parameters for better performance are indicated charging refrigerant 800 g and compressor speed 1700 rpm.