• Journal of Mechanical Science and Technology
• /
• v.17 no.1
• /
• pp.1-10
• /
• 2003

This paper summarizes the results of the fatigue test of four composite bridge decks in extreme temperatures (-30$^{\circ}C$ and 50$^{\circ}C$ ). The work was performed as part of a research program to evaluate and install multiple FRP bridge deck systems in Dayton, Ohio. A two-span continuous concrete deck was also built on three steel girders for the benchmark tests. Simulated wheel loads were applied simultaneously at two points by two servo-controlled hydraulic actuators specially designed and fabricated to perform under extreme temperatures. Each deck was initially subjected to one million wheel load cycles at low temperature and another one million cycles at high temperature. The results presented in this paper correspond to the fatigue response of each deck for four million load cycles at low temperature and another four million cycles at high temperature. Thus, the deck was subjected to a total of ten million cycles. Quasi-static load-deflection and load-strain responses were determined at predetermined fatigue cycle levels. Except for the progressive reduction in stiffness, no significant distress was observed in any of the composite deck prototypes during ten million load cycles. The effects of extreme temperatures and accumulated load cycles on the load-deflection and load-strain response of FRP composite and FRP-concrete hybrid bridge decks are discussed based on the experimental results.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.6
• /
• pp.166-174
• /
• 2013

This study investigates the strength durability on the results of structural and vibration analysis due to the shape of excavator wheel. As model 2 has the least stress by comparing three models with maximum equivalent stress, model 2 has most durability among three models at static analysis. Maximum equivalent stress is shown at the bottom part contacted with ground and this part on wheel is most affected by load in cases of all models. Safety factor can be decided with the value of 2.3 by considering the yield stress of this model. The range of maximum harmonic response frequencies becomes 6900 to 7000Hz. As model 2 has the least total deformation and equivalent stress at these critical frequencies, model 2 has the most durability at vibration analysis among three models. The structural and vibration analysis results in this study can be effectively utilized with the design of excavator wheel by investigating prevention and durability against its damage.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.1176-1185
• /
• 1993

The purpose of this study is to propose a new dynamic model of wheels and agricultural tractors through verification of the existence of " lift resistance " and "perpendicular adhesion" which also can be called " contra-retractive adhesion". The existence of these forces was proved through experiments including the development of a sensor which can measure the forces acting on a wheel accurately. Consequently " perpendicular adhesion ratio" which is defined as the ratio of the perpendicular adhesion to the distributed load was observed to be in the range of 0.05 to 0.3. This means the influence of the " lift resistance " is comparable to that of motion resistance in wheel dynamics. The perpendicular adhesion ratio was observed to decrease logarithmically with the increase of ground contact pressure, and to increase linearly with increase of the travel speed of the wheel . Some examples to express the new dynamic model compared to the conventional dynamics are explained.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.7
• /
• pp.626-632
• /
• 2013

When a conductive rod is put within rotating axial magnet wheels arranged parallel, three-axial magnetic forces generate on the rod. In some region, the forces has a property of negative stiffness, thus they can be applied to noncontact conveyance of the rod without a control load. Apart from the passive driving, the magnet wheel should be controlled for the rod to be stayed at the still state or be moved in a specified velocity. But, because a control input is just the rotating speed of the magnet wheel, the number of input is less than that of variables to be controlled. It means that levitation force and thrust force increase at the same time for increasing wheel speed, resulting from a strong couple between two forces. Thus, in this paper, a novel method, in which the longitudinal motion of the rod is controlled indirectly by the normal motion of the rod with respect to the wheel center, is introduced to manipulate the rod without mechanical contact on space.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.2
• /
• pp.79-84
• /
• 2012

This study consist of two parts. One is development of a self-propelling vinyl remover which was already reported at the previous paper. This is the second part of the study. For the study, an attached vinyl remover was developed. It was consisted of connecting tractor to bucket, removing bucket from tractor, and the process was the tractor's assistance hydraulics. In the case of an attached vinyl remover, the vinyl was twisted 0.5times per 30~85cm length. The bobbin's diameter was 190mm and it's stable travelling speed was 1m/s. The revolution of the remover wheel was 90rpm to maintain the wheel's linear velocity. As seen at performance test at the field which had 950mm ridge intervals and 10 a area, the average working speed was 1m/s and the turning time was 20seconds. Therefore, the working performance was 24.5min/10a. The efficiency of used vinyl remover was 97% and working conditions were good.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.3
• /
• pp.451-458
• /
• 2012

This study aims at the structural analysis with fatigue according to the configuration of railway vehicle wheel. Maximum equivalent stress or deformation is shown at the lower face in contact with wheel and rail. As model B has the maximum stress or deformation which becomes lower than model A, model B is shown to have more durability than model A. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to $-10^{11}$ Pa and the amplitude stress of 0 to $10^{10}$ Pa, the possibility of maximum damage becomes 3%. This stress state can be shown with 6 times more than the damage possibility of 'SAE Bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design of railway vehicle wheel by prevention and durability against its damage.

• Journal of the Korean Society of Safety
• /
• v.33 no.2
• /
• pp.145-151
• /
• 2018

In this study, the track-bridge interaction analysis was performed using an analytical model considering the track structure, thereby taking into account the linear conditions (R=650 m, cant variation $160{\pm}60mm$) and the dynamic characteristics of the bridge. As a result of the study, the allowable speed on the example bridge considered was calculated at 200 km/h based on vertical deflection, vertical acceleration, and irregularity in longitudinal level, but was also evaluated at 170km/h based on the coefficient of derailment, wheel load reduction, and lateral displacement of the rail head. It is considered desirable to set the speed 170km/h to the speed limit in order to secure the safety of both the bridge and the track. It is judged that there will be no problems with ensuring rail protection and train stability in the speed band.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.726-731
• /
• 2004

Bogie is the connection device between carbody and wheel in railway vehicles. It is the core part that exert a important effect on the passenger safety and running safety. Bogie largely consists of bogie frame, suspension, brake, wheel set. Static and Dynamic load have acted on it complexly. When the bogie is designed, finite element method, static load test, fatigue test, running test should be considered. Some bogie frame of high speed railway freight car have the problem. It's end beam was cracked. The crack of the end beam have a bad effect on brake system. In that case, the cars would be in danger of derailment.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.2
• /
• pp.10-17
• /
• 2012

This paper presents an improved iron loss model, for the computation of the no load iron loss in the stator core of the in-wheel permanent magnet synchronous motors (PMSM), for the cases of with and without stator skew. 2-D analytical model is used for the computation of tooth and yoke flux densities of the in-wheel PMSM. The no load iron loss computed by the improved iron loss model, for the cases of with and without skew is compared with the finite element method (FEM) and the results show good consistency.

• Journal of the Korea Institute of Building Construction
• /
• v.6 no.1 s.19
• /
• pp.67-72
• /
• 2006

There are a lot of problem about waterproofing membrane coating for concrete deck of bridge and waterproofing sheets for concrete of deck of bridge because it couldn't confirm waterproofing's defeat after construction. These problems make a waterproofing material damage and condrete deck of bridge damage. So It needs a lot of money for repair work and reinforcement work. Therefor the structure slab of using waterproofing material protect invasion of water. Also, Concrete deck of bridge need a endurance permeability for the reduction repair payment. In this study, An experimental study on the quality standardization test method waterproofing layer on working of live load.