• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.56-60
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• 1996

An experimental study on the grinding temperature and Acoustic Emission(AE) signals due to the different shapes of wheel was conducted. The grinding characteristics by slotted shapes of wheel changed by width and helical angle, were compared with those by general one. Lower grinding temperature was obtained for 30$^{\circ}$ helical angle with 10mm width, Root Mean Square(RMS) values of AE signals were higher for slotted wheel rather than general one.

• 한국정밀공학회지
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• 제30권1호
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• pp.47-52
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• 2013

In order to operate a search and rescue robot in hazardous area, the robot requires high mobility and adaptable locomotion for moving in unpredictable environments. In this paper, we propose the deformable soft wheel robot that can produce three kinds of driving modes; caterpillar driving mode, normal wheel driving mode, legged-wheel driving mode. The robot changes its driving mode as it faces the various obstacles such as a small gap, stairs etc. Soft film and composite materials are used for fabrication of deformable wheel structure and Shape Memory Alloy (SMA) coil spring actuators are attached on the structure as an artificial muscle. Film lamination and an composite manufacturing process is introduced and the robot design is required to be modified and compromised to applying the manufacturing process. The prototype is developed and tested for verifying feasibility of the deformable wheel locomotion.

• International Journal of Railway
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• 제6권4호
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• pp.148-154
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• 2013

This article has tried to review the maximum contact stresses in the contact area of the wheel and rail as a result of lateral movement of the wheel on rail by taking advantage from Hertz theory. Since wheel movement on rail is accompanied by lateral movement due to wheel profile conisity, so the contact point of wheel and rail is not constant and the contact stresses are therefore changeable in every single moment. Since the shape of rail profile and rail inclination, wheel diameter and the mechanical properties of the wheel and rail are effective on the stresses of contact area, these parameters have been studied by applying Hertz theory. This article aims to calculate the contact stresses in different parts on the wheel surface by using Hertz theory.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.66-71
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• 2006

A geometric contact conditions of wheel/rail affect the dynamic behavior of rolling stock. Mechanical force acted on the wheel/rail causes excessive wear and increase the maintenance cost. In this study, we have studied the dynamic behavior of the urban railway vehicle with new and worn wheel by VAMPIRE program. And we have tested the accelerations of wheelset on the conventional line. The results of simulation are compared with the measuring data of field test. It shows that the acceleration of worn wheel is greater than the acceleration of new wheel in the straight track line but on the contrary, the acceleration of new wheel is greater than the acceleration of worn wheel in curved track. That results explain that the new wheel is worn out greater than the worn wheel in curved track line and need to be maintained more seriously when running in curved track line.

• 로봇학회논문지
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• 제14권3호
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• pp.186-190
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• 2019

When problems occurred in the unstable and/or extreme terrain environment, formal field-driving robots were unable to provide any other options such as the transformation of the wheel and body structure, and so on. For such reason, this paper proposed a novel type of integrated wheel mechanism that can be operated as a conventional driving wheel mode and hybrid wheel-leg mode in order to be negotiated in an unstable terrain environment. The mechanical effect of the proposed variable wheel mechanism was analyzed considering the geometric constraint and power requirement of the actuator for the transformation. In addition, we designed and manufactured the prototype of field-driving robot, which reliably control the variable wheel shape. Finally, the effectiveness of the variable wheel mechanism was verified by preliminary experimental approach.

• 한국공간구조학회논문집
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• 제17권1호
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• pp.31-40
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• 2017

The objective of this study is to analysis the mechanical characteristics and nonlinear behaviors on the geometric nonlinear behavior of a cable spoke wheel roof system for long span lightweight roof structures. The weight of a cable spoke wheel roof dramatically can reduce and the cable roof system can easily make the required rigidity and shape by the sag ratio and pretension forces. Determining the pretension and initial sag of cable roof system is essential in a design process and the shape of roof is changed by pretension. The nonlinear behavior of flexible cable system has greatly an affect on the sag and pretension. This paper will be carried out analyzing and comparing the tensile forces and deflection of a cable spoke wheel system for the large span retractable roof, and analyzed to deflections and tensile forces by the post height of center hub. The double arrangement of a spoke wheel system with reverse curvature works more effectively as a load bearing system, the pretension can easily increase the structural stiffness. The cable truss system can carry vertical load in up and downward direction, and act effectively as load bearing elements.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1238-1245
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• 2000

One of the main causes of severe wear or crack initiation in wheel and rail is the contact stress due to wheel-rail contact. First, we obtain contact stress due to the rail mounting slope using the finite element method. Second, the shape design based on more reasonable contact stress analysis rather th~n a general Hertzian contact theory is investigated in order to reduce the contact stress. The optimum -design is performed using the simple 2-D finite element model and its results are verified by 311) finite element analysis.

• 대한기계학회논문집A
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• 제23권11호
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• pp.2033-2039
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• 1999

One of the main causes of severe wear or crack initiation in wheel and rail is the contact stress due to wheel-rail contact. In this paper, the shape design based on more reasonable contact stress analysis rather than a general Hertzian contact theory is investigated in order to reduce the contact stress. The optimal design is performed using the simple 2-D finite element model and its results are verified by 3-D finite element analysis.

• 한국정밀공학회지
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• 제29권2호
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• pp.193-200
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• 2012

Wheel loader is one of the construction machinery capable of variety of tasks and the demand on functional diversity and structural reliability is growing. As a study on the optimal shape design of front axle for wheel loader through the design of experiments, this paper assessed the design parameters affecting the maximum stress. As a result, a value of 126.77 MPa of minimum stress was obtained, and optimal factors showed the values of w = 100.0 mm, ${\theta}=40^{\circ}$ and R = 118 mm. It showed an accuracy of 98.7% compared with the structural analysis.

• 한국공작기계학회논문집
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• 제14권3호
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• pp.122-127
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• 2005

The styling of automobile wheels and their effect on vehicle appearance has increased in importance in recent years. The wheel designer has been given the task of insuring that a wheel design meets its engineering objectives without affecting the styling theme. The wheel and tire system is considered as a vehicle component whose dynamic modal information of the tire/wheel system are employed in the modal synthesis model of the vehicle. The vibration characteristics of a automobile wheel play an important role to judge a ride comfort and quality for a automobile. In this paper, the vibration characteristics of a Al-alloy and steel wheel for automobile are studied. Natural frequency, damping and mode shape are determined experimentally by frequency response function method. Results show that wheel material property, size and design are parameter for shift of natural frequency and damping.