• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.656-661
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• 2003

Modem reciprocating air compressors have tendency to a multi-stage W-type or V-type cylinder arrangement for the purpose of high outlet pressure, compactness and low vibration and noise. A valid counter weight calculation method using the complex expression is proposed for reducing the inertia forces of the compressor. Counter weight removes only 1st forward whirl component. Counter weight formulations are applied to the six various compressor structures which are (a) 1 cylinder single-throw crank shaft, (b) 2 cylinder single-throw crank shaft (c) 2 cylinder double-throw clank shaft, (d) 3 cylinder single-throw crank shaft, (e) 4 cylinder single-throw crank shaft and (f) 4 cylinder double-throw crank shaft. The improvement of performance is verified through available vibration test.

• 한국기계가공학회지
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• 제6권3호
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• pp.105-111
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• 2007

The type of pedestrian accident can be characterized by vehicular frontal shape and the height of pedestrian. The trajectory of pedestrian after collision by passenger car is different from that by bus due to vehicular frontal shape. The frontal shape of SUV vehicles is dissimilar to passenger car and bus. So, the trajectory and throw distance of pedestrian by SUV vehicles is not the same of passenger car and bus. In this paper, a series of pedestrian kinetic simulation were conducted to inspect the difference in throw distance between SUV vehicle and passenger car and bus by PC-CRASH that is the program for kinetic analysis of articulated body. From the results, if the height of pedestrian is taller than 1.70m, there is no difference in throw distance between SUV vehicle and passenger car, but if the height of pedestrian is about 1.55m throw distance of SUV vehicle is about 4m longer than that of passenger car at each impact speed. The throw distance of pedestrian by Bus is shorter than that of passenger car and SUV at each impact speed.

• 한국기계가공학회지
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• 제6권3호
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• pp.71-76
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• 2007

The fatalities of pedestrian account for about 40.0% of all fatalities in Korea 2005. Vehicle-Pedestrian accident generates trajectory of pedestrian. In pedestrian involved accident, the most important data to inspect accident is throw distance of pedestrian. The throw distance of pedestrian can be influenced by many variables. The variables that influence trajectory of pedestrian can be classified into vehicular factors, pedestrian factors, and road factors. Vehicular factors are the frontal shape of vehicle, impact speed of vehicle, the offset of impact point. Many studies have been done about the relation between impact speed and throw distance of pedestrian. But the influence of the offset of impact point was neglected. The influence of the offset of impact point was analyzed by Working Model, and the trajectory of pedestrian, dynamic characteristics of multi-body were analyzed by PC-CRASH, a kinetic analysis program for a traffic accident. Based on the results, the increase of offset reduced the throw distance of pedestrian. However box type vehicle just like bus, the offset of impact point did not influence the throw distance of pedestrian considerably.

• 한국운동역학회지
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• 제22권2호
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• pp.183-191
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• 2012

The objective of this study was to evaluate the plantar foot pressure of skilled and unskilled players during a free throw. The experiment performed here in measured the movement route of the mean foot pressure, maximum foot pressure, and center of pressure in four event zones (ready, maximum knee flexion, release event, and maximum knee extension) for both groups while they were wearing the plantar foot pressure measurement equipment under identical conditions. The major findings are as follows. When getting ready (RD) during a free throw, the skilled player group had higher mean and maximum foot pressures, although neither variable showed significant differences statistically. For the maximum knee flexion (MF) during a free throw, the skilled player group had higher mean and maximum foot pressures, but only the mean foot pressure significantly differed statistically. For the release event (RE) during a free throw, the unskilled player group had higher mean and maximum foot pressures, but only the mean foot pressure significantly differed statistically. During the maximum knee extension (ME) of a free throw, the unskilled player group had a higher mean foot pressure, and the skilled player group had a higher maximum foot pressure. No significant correlation was found between the two groups. For the skilled player group, movement towards the center of pressure showed a stable form that moved from the rear to the front and from side to side during a free throw. For the unskilled player group, movement towards the center of pressure was unstable, which made it impossible to move from the rear to the front and from left to right.

• 한국자동차공학회논문집
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• 제18권3호
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• pp.104-109
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• 2010

The fatality of pedestrian accounts for about 21.2% of all fatality at 2007 year in Korea. In car to pedestrian accident it is very important to inspect the throw distance of pedestrian after collision for exact reconstructing of the accident. The variables that influence on the throw distance of pedestrian can be classified into the factors of vehicle and pedestrian, and road condition. It was simulated by PC-CRASH, a kinetic analysis program for a traffic accident in sedan type vehicle and SPSS program was used for regression analysis. From the results, the throw distance of pedestrian increased with the increasing of vehicle velocity, and decreased with the increasing of impact offset. Also it decreased with the increasing of velocity of pedestrian at accident, and throw distance at the road condition of wet was longer than that at dry condition. Finally, the regression model of sedan type vehicle on the throw distance of pedestrian was as follows; $$dist_i=2.39-0.11offset_i+0.59speed_i-545height_i-0.25walk_i+2.78wet_i+{\epsilon}_i$$.

• 한국기계가공학회지
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• 제11권2호
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• pp.92-97
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• 2012

In the present the usage of bicycle has increased steeply due to well-being and convenient way of movement. In car to bicycle accident, the throw distance of bicycle is very important factor for estimating collision situation. In this study, simulations and collision tests in actual car to bicycle were executed for obtaining throw distance of bicycle. The simulations were executed by PC-CRASHTM s/w with vehicle of sedan type. Sand bags were used for the behavior of bicyclist instead of dummy and factors considered were vehicle velocity, the crashed angles and part of bicycle to vehicle, and bicycle was adult type. From the results, the throw distances of tire collision of 00 was longer than that of 450 tire crash, and the throw distances of 900 frame crash were longer than those of 450 frame crash. With based on actual crash tests and simulations, restitution coefficient of between vehicle and bicycle was estimated as 0.1. Finally the increaser vehicle velocity the longer the throw distances of bicycle and the simulation results were relatively good agreement to the results of experiment.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.106-111
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• 2012

Recently the usage of bicycle has increased steeply in Korea owing to traffic culture of well- being. In a car to bicycle accident investigation, the throw distance of bicycle is very important factor for reconstructing of the accident. The variables that influence on the throw distance of bicycle can be classified into the factors of vehicle and bicycle. Simulations and collision tests in actual car to bicycle accident were executed for obtaining throw distance of bicycle. The simulations were done by PC-$CRASH^{TM}$ and for actual crash tests sand bags were used for the behavior of bicyclist instead of dummy. Factors considered were vehicle velocity and the moving angles of bicycle, also the types of bicycle and vehicle were fairy cycle and automobile, respectively. From the results, the throw distances of a head-on tire collision of $0^{\circ}$ direction was longer than that of tire crash test of $45^{\circ}$ direction, and the throw distances of a head -on frame crash test of $90^{\circ}$ direction was longer than that of frame crash test of $45^{\circ}$ direction. In addition restitution coefficient between vehicle and bicycle was estimated as about 0.1 with based on actual crash tests. Finally the increaser vehicle velocity the longer the throw distances of bicycle, and the results of simulation were relatively good agreement to the experimental results.

• 동력기계공학회지
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• 제13권5호
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• pp.76-81
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• 2009

The fatalities of pedestrian account for about 21.2% of all fatalities at 2007 year in Korea. To reconstruct exactly the accident, it is important to calculate the throw distance of pedestrian in car to pedestrian accident. The frontal shape of SUV vehicle is dissimilar to passenger car and bus, so the trajectory and throw distance of pedestrian by SUV vehicle is not the same of passenger car and bus. The influencing on it can be classified into the factors of vehicle and pedestrian, and road factor. It was analyzed by PC-CRASH for simulation, and SPSS s/w was used for regression analysis. From the simulation results, the maximum impact energy of multi-body of pedestrian was occurred to that of torso body at the same time. And the throw distance increased with the increasing of impact velocity, and decreased with the increasing of impact offset. Also it decreased with the increasing of velocity of pedestrian at accident, and the throw distance of wet road was longer than that of dry road. Finally, the regression analysis model of SUV(Nissan Pathfinder type)vehicle in car to pedestrian accident was as follows; $$disti_i=-0.87-0.11offseti_i+0.69speed_i-4.27height_i+0.004walk_i+0.63wet_i+{\epsilon}_i$$.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.191-194
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• 2003

A crank throw, which is one of the part of crankshaft for a large diesel engine, is manufactured by both closed die forging and open die forging. For the improvement of productivity the open die forging method is usually adopted to manufacture it these days. In case of the open die forging for the crank throw, a preform shape is very important because it seriously affects final dimensions of the product. The purpose of this study is to investigate affective factors of the preform to obtain a good shape of final product through simulation and the results are compared to downsized lead experiments.

• 설비공학논문집
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• 제14권3호
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• pp.206-213
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• 2002

In this paper, the flow characteristics of an axial fan spraying isothermal compact jet in a confined space were investigated by the experimental methods, the numerical method, and the free jet theory According to the results, the numerical result and the experimental result are agreed well qualitatively and different quantitatively within $\pm1.0%$ for the centerline velocity, the entrainment ratio, and the maximum throw. However, the free jet theory can reasonably predict the centerline velocity except the entrainment ratio and the maximum throw. In other words, the entrainment ratio and the maximum throw by 1.he free jet theory are hard to estimate the characteristics of jet because of restriction of c confined space.