• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.194-194
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• 2004

개인용 로봇의 촉각기능을 담당할 수 있는 유연성 기반 인공피부센서 시스템을 설계 및 제작하였다. 수직력을 측정할 수 있는 64 개의 FSR 센서(Techstorm Co.)와 전단력을 동시에 측정할 수 있는 1 개의 PVDF 필름(PSI Co.)을 융합하여 인공피부센서 시스템을 제작하였다 제작된 촉각센서는 10 cm x 10 cm 크기로 임의의 물체가 접촉할 경우 형상을 측정할 수 있으며 또한 물체표면의 거칠기 상태를 판단할 수 있다. 한편, 3축 로드셀 기반 평가 시스템을 제작하여 센서의 수직력을 평가하였으며 PVDF 필름을 통한 접촉하는 대상의 거칠기 평가는 주파수 분석으로 평가하였다.(중략)

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.5
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• pp.772-780
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• 1987

The normal and tangential belt forces for two types of flat belts are measured and compared. From friction theory, ti was assumed that tangential friction is proportional to the actual contact area $A_{a}$ and $A_{a}$ is proportional to normal pressure P; i.e., $A_{a}$ .var.P$^{n}$ . For a flat belt with cloth backing, the n=2/3 is obtained for the constant of belt surface model. For a flat belt with rubber backing, the n=0.9 to n=1.0 is suggested as a surface model constant. The theoretical equation developed in this paper showed agood with the experimental results.

• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.14-18
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• 2014

Wheel/rail contact is a significant problem in railway dynamics. In this paper, the wheel/rail contact is examined analytically and numerically as a contact problem between two cylinders where torque and friction have effect. Furthermore, the contact of a real wheel and rail is investigated numerically where the normal and shear force act. This study demonstrates that the wheel/rail contact is a process that generates traction force through creep where rolling and sliding occurs simultaneously depending on the shape of the wheel and rail, and the friction coefficient between them.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.04a
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• pp.108-116
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• 1996

본 논문에서는 하중부와 방법을 추(dead weight)와 공압(pneumatic)을 이용한 방법에서 스프링을 이용한 방법을 추가하였으며, 압축형 스프링을 선택적으로 사용하여 마찰시험기 수직방향에서의 강성을 큰 변화 폭으로 변화시켰다. 또한 선행된 연구를 통하여 수직하중의 변동량에 크게 영향을 미치는 것으로 알려진 바 있는 디스크 시편의 misaligment 효과를 상사하고 극대화 하기 위하여 본 논문에서는 경사진 디스크 시편을 추가로 사용하였다. 상기조건으로 마찰시험기 시스템의 각 하중부과 방법과 수직강성 변화가 마찰특성에 미치는 영향을 실험적으로 측정 평가하였으며, 마찰시험기 동특성계 모델의 이론적 해석을 통하여 마찰특성 변화를 고찰하였다. 또한, 미끄럼 접촉 시의 수직력과 마찰력을 측정하고, 데이터의 통계적 처리방법에 따른 마찰계수의 변화 특성도 평가하였다.

• The korean journal of orthodontics
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• v.40 no.5
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• pp.304-313
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• 2010

Objective: The aim of this study was to evaluate the occlusal force and contact area and to find its associating factors in Koreans. Methods: Occlusal force and contact area in maximum intercuspation were measured using the Dental $Prescale^{(R)}$ system in 651 subjects (15 with normal occlusion, 636 with various malocclusions divided into subgroups according to the skeletal pattern, Angle's molar relationship, age and gender). Results: Occlusal force of the normal occlusion group ($744.5{\pm}262.6N$) was significantly higher than those of the malocclusion group ($439.0{\pm}229.9N$, $p$ < 0.05). Occlusal force was similar regardless of differences in ANB angle or Angle's molar classification, however the increase in vertical dimension significantly reduced occlusal force ($p$ < 0.05). Conclusions: Occlusal force was significantly lower in the malocclusion group compared to the normal occlusion group, and in females compared to males, but it was not affected by age, antero-posterior skeletal pattern or molar classification. Although a hyperdivergent facial pattern indicated lower occlusal force compared to a hypodivergent facial pattern, the differences in skeletal pattern were not the primary cause of its decrease, but a secondary result induced by the differences in occlusal contact area according to the facial pattern.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.554-570
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• 1990

he rolling contact behaviors between a smooth ball and a flat rough surface under dynamic load are intricately affected by many factors, such as the diameter of a ball, normal load and the roughness of a flat surface etc. Accordingly, the experimental study is done to find them on the base of elastic hysteresis loss as theoretical approach is very difficult. The experimental apparatus composed of damped-free vibration system is used. This paper investigates the damping characteristics on the rolling contact area through rolling friction force and logarithmic decrement versus displacement obtained in accordance with the variations of those factors, and presents a new experimental method to find out contact width using the relations of logarithmic decrement and rolling friction force with displacement.

• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.27-32
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• 2006

In this paper, the contact stress and friction force between multi-balls and rolling friction contact surfaces of two cylinders have been presented using a finite element analysis. The multi-balls for a rolling friction motion may be contacted with a reciprocating mechanism of a parallel cylinder and a misaligned cylinder in a LPG filling unit. The FEM computed results indicate that SiC ceramic and SUS 304 balls show a high contact stress and friction force on the contact spot of rolling balls. But the PEEK balls show a low contact stress and friction loss due to a high flexibility of a PEEK polymer. In this study, we may recommend SiC and SUS 304 balls for high compressive loadings between a multi-ball and a cylinder contact mechanisms and PEEK balls for a low compressive force. And the misalignment between two cylinders should be restricted for a low contact stress and friction loss, especially.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.77-88
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• 2007

A micromechanics-based model to simulate the elastic and elastic-plastic behavior of granular soils is developed. The model accounts for the fabric anisotropy represented by the statistical parameter of the spatial distribution of contact normals, the evolution of fabric anisotropy as a function of stress ratio, the continuous change of the co-ordination number relating to the void ratio, and the elastic and elastic-plastic microscopic contact stiffness. Using the experimental data for metallic materials, the elastic-plastic contact stiffness is derived as a power function of the normal contact force as well as the contact force initiating the yielding of contact bodies. To quantitatively assess microscopic model parameters, approximate solutions of cross-anisotropic elastic moduli are derived in terms of the micromechanical parameters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.411-420
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• 2000

This paper presents a new method for calculating contact position and contact force. The proposed method calculates accurate contact position by introducing intermediate parameters. Accurate contac t force can be obtained by solving reduced equations of motion iteratively. This method can be applied to calculate not only contact force on contact points but also contact force on kinematic joints such as a rotational joint and a translational joint. Four numerical examples are given to demonstrate the effectiveness of the proposed algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.130-130
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• 2004

본 논문에서는 RF 스위치의 엑추에이터로 사용하기 위한 수평구동형 박막형 PZT 엑추에이터의 설계, 제작 및 시험에 관한 것이다 기존의 RF 스위치들은 대부분 수직 방향의 접촉 방식을 채택하고 있고, 대부분 구조체가 두껍지 않은 막으로 이루어져 있어서, 엑추에이터로부터 힘을 충분히 전달받지 못한다. 이로 인해, 접촉력이 상대적으로 작게 되어, 접촉저항을 줄이기 위한 접촉압력을 내기 위해 접촉 면적을 줄일 수밖에 없게 된다. 따라서, 본 연구에서는 효과적인 힘의 전달이 가능한 수평방향의 접촉 방식과 상대적으로 큰 힘을 낼 수 있는 PZT 엑추에이터를 사용하고자 한다.(중략)