• Journal of Chest Surgery
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• v.42 no.3
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• pp.384-387
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• 2009

Radial artery aneurysm is an extremely rare disease and this is usually caused by iatrogenic trauma such as arterial cannulation. Most traumatic aneurysms in the extremities are false aneurysms and most cases have occurred at the level of the wrist. Very few true aneurysms of the radial artery have been reported, with most of them being iatrogenic. A right handed 38-year-old female had a true aneurysm of the distal radial artery in the thenar groove of the palm. The patient had a history of excessive handclapping and the injury was suggestive of repetitive occupational injury due to scissoring. She underwent surgical treatment for the aneurysm of the radial artery in the thenar groove of the palm of her hand.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3149-3158
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• 1994

In this paper, using the formulation of dynamic equivalent load considering the effects of moment load and the equation to estimate the cage rotational speed, the new life equation of deep groove ball bearing under radial and moment loads was proposed. Fatigue life test apparatus with the measuring equipment of shaft and cage speed was designed and developed to be capable of subjecting combined radial and moment load. Fatigue life tests were executed by sudden death test method and the reliability of fatigue lives was evaluated by Weibull distribution analysis. From the results of fatigue tests and analysis, the relationships between film parameters and life adjustment factors were acquired. And it was turned out that so as to estimate the effect of moment load on fatigue life, the life adjustment factor as well as the dynamic equivalent load must be taken into account.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1340-1347
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• 2002

Finite element simulations are being widely used to increase the efficiency and effectiveness of design of bulk metal forming processes. In such simulations, proper consideration of friction condition is crucial in obtaining reliable results. For this purpose, tip test based on backward extrusion was proposed recently. In this lest, a cylindrical billet is positioned in a shallow groove of a counter punch for centering purpose and formation of a radial tip is induced on the extruded end of the workpiece. In this study, the effect of centering groove on tip test was investigated. The quantitative ratio of the shear friction factors between the punch and die was numerically determined depending on the shape of centering groove. Also, surface expansion and pressure distribution along the punch and die were considered in order to better understand the reason that friction condition at the punch compared to the one of die was more severe.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.15-21
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• 2008

It is generally known that the PRAT(Plysteer Residual Aligning Torque) is one of indicating a performance factors of a tire for assessing the vehicle pull, also tire pattern shape, which means lateral groove angle, is very important tire design factor in relation to the PRAT. Lateral grooves of tire pattern are widely divided into center and shoulder parts. So, this paper has studied the correlation between the PRAT and their lateral groove angles using FEM. Especially, the steady state rolling analysis among tire rolling analysis methods has been used for the PRAT performance study. Firstly, analysis result data have been compared with the experimental data to validate FE analysis for PRAT. Next, the PRAT due to the lateral groove angle about PCR(Passenger Car Radial) tire and SUV tire has been analyzed. The tendency of the PRAT due to the lateral groove angles can be used as a guide line for the tire design in relation to vehicle pull.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.740-745
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• 2001

There are two kinds of method to calculate the equivalent friction coefficients at V groove. One is to consider the firction in radial direction. The other is to neglect the friection in radial direction. The values calculated from the two methods is different of which ratio is in the range from two times to five times. So it is necessary to study which is correct in the view of force equilibrium and machine design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.2
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• pp.141-148
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• 2008

A numerical simulation of brushless DC motor is performed to elucidate thermo-flow characteristics in winding and bearing with heat generation. Rotation of rotor and blades drives influx of ambient air into the rotor inlet. Recirculation zone exists in the tiny interfaces between windings. The flow separation causes poor cooling performance in bearing part and therefore the redesign of the bearing groove is required. The design parameters such as the inlet location, geometry and bearing groove threshold angle have been selected in the present simulation. As the inlet location moves inward in the radial direction, total incoming flow rate and heat transfer rate are increased. Total incoming flow rate is increased with increasing the inlet inner length. The effect of the bearing groove threshold angle on the thermal performance is less than that of other design parameters.

• Tribology and Lubricants
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• v.38 no.5
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• pp.213-221
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• 2022

This paper presents performance measurements of pressure drop and leakage flow rate of test flat seals with asymmetric inclined grooves. This study aims to reveal the influence of groove shapes, often machined in radial film riding-face seals, in forming a hydrodynamic wedge on leakage performance. A test facility was developed, and test seals were manufactured to study the effects of the inlet pressure level, ratio of inlet to outlet pressure, seal groove length, and seal groove height on the steady-state pressure drop and leakage performance. A series of tests were conducted, and the test data were compared to the predictions from a simple and efficient mathematical model using a one-dimensional Reynolds equation. The test results revealed that an increase in the inlet pressure increased the pressure drop through the test seals. The leakage flow rate increased significantly as the inlet pressure and ratio of the inlet to outlet pressure increased. The groove shape also affects seal performance. An increase in the groove length and height resulted in an evident increase in the leakage flow rate. The simple model predictions underestimated the leakage flow rates but showed good agreement with the trend in the measurements for all test operating conditions and changes in the groove shape.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.304-311
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• 2001

This research numerically analyzes the dynamic characteristics of a coupled journal and thrust hydrodynamic bearing due to its groove location which has the static load due to the weight of a rotor in the axial direction and the dynamic load due to its mass unbalance in the radial direction. The Reynolds equation is transformed to solve a plain member rotating type of journal bearing(PMRJ), a grooved member rotating type of journal bearing (GMRJ), a plain member rotating type of thrust bearing (PMRT) and a grooved member rotating type of thrust bearing (GMRT). FEM is used to solve the Reynolds equations in order to calculate the pressure distribution in a fluid film. Reaction forces and friction torque are obtained by integrating the pressure and shear stress along the fluid film, respectively. Dynamic behaviors, such as whirl radius or floating height of a rotor, are determined by solving its nonlinear equations of motion with the Runge-Kutta method. This research shows that the groove location affects the pressure distribution in the fluid film and consequently the dynamic performance of a HDD spindle system.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.12a
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• pp.51-56
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• 1993

The conical bearing can be used to support the radial and thrust load simultaneously. Two circumferential grooves with discrete hole restrictions are made on the bearing surface in order to increase stiffness. In this paper, the dynamic characteristics of this type of bearings are calculated such as stiffness and champing coefficients. As a results of theoretical analysis, it is verified that there exist the groove depth and distance between two grooves which produce the maximum stiffness at the given bearing dimensions.

• Tribology and Lubricants
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• v.10 no.1
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• pp.56-61
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• 1994

The conical bearing can be used to support the radial and thrust load simultaneously. Two circumferential grooves with discrete hole restrictions are made on the bearing surface in order to increase stiffness. In this paper, the dynamic characteristics of this type of bearings are calculated such as stiffness and damping coefficients. As a results of theoretical analysis, it is verified that there exist the groove depth and distance between two grooves which produce the maximum stiffness at the given bearing dimensions.