• Journal of the Ergonomics Society of Korea
• /
• v.29 no.4
• /
• pp.709-713
• /
• 2010

The objective of this paper is to report how workers' actively participate in a participatory ergonomics (PE) program, and how this program resulted in improved working conditions and decreased occurrence of work-related musculoskeletal disorders (WMSDs). A major tire manufacturing company in Korea was studied. Most of the activities in the PE program were designed and actually practiced by the workers and their union. The results revealed some positive effects of applying a PE program to the employees. It was shown that incidence of the WMSDs as well as the lost work days and the economic cost incurred by the WMSDs decreased with the PE program.

• Journal of Korea Foundry Society
• /
• v.28 no.5
• /
• pp.217-220
• /
• 2008

본 연구에서는 유한요소법을 적용한 수치해석을 이용하여 타이어 제조용 금형을 생산하기 위해 사용되는 주조재의 열적 특성에 관하여 조사해 보았다. 고 품질의 정밀도가 좋은 타이어를 제조하기 위해, 일반적으로 타이어 제조용 금형의 주조재로 많이 사용되고 있는 알루미늄 합금과 비교 대상으로 연강을 선정하여 각각의 주조재에 대한 응고과정에서의 온도분포와 응력분포 결과를 수치적으로 계산해 보고 결과를 예측해 보았다. 수치해석을 통한 결과에서, 알루미늄 합금을 사용한 금형의 냉각과정 동안의 온도분포는 연강에 비해 보다 더 안정적으로 나타나는 것을 확인하였으며, 응력분포 결과 또한 알루미늄 합금 금형이 연강에 비해 정밀도를 향상시키고 좋은 품질의 제품을 얻는 데 보다 나은 것으로 나타났다. 그리고 금형의 온도분포와 응력분포는 금형의 냉각과정 동안 주조재의 초기 냉각온도에 의해 크게 영향을 받는 것으로 사료된다. 마지막으로, 이러한 수치해석에 의한 금형의 열적 특성 예측은 향후 고품질, 고정밀도의 금형 생산을 위한 예비성능평가 방법과 경제적 측면에서 매우 유용하게 활용할 수 있을 것으로 보인다.

• International Journal of Precision Engineering and Manufacturing
• /
• v.5 no.3
• /
• pp.26-34
• /
• 2004

This paper examines the usefulness of a Brake Steer System(BSS), which uses differential brake forces for steering intervention in the context of Intelligent Transportation Systems(ITS). In order to help the car to turn, a yaw moment control was achieved by altering the left/right and front/rear brake distribution. This resulting yaw moment on the vehicle affects lateral position thereby providing a limited steering function. The steering function achieved through BSS was used to control lateral position in an unintended road departure system. A 8-DOF nonlinear vehicle model including STI tire model was validated using the equations of motion of the vehicle. Then a controller was developed. This controller, which is a PID controller tuned by Ziegler-Nichols, is designed to explore BSS feasibility by modifying the brake distribution through the control of the yaw rate of the vehicle.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.1
• /
• pp.93-100
• /
• 1994

5-axis CNC machining is being used in the manufacturing of tire mold, screw, and turbine blade because it can produce complex workpiece more efficiently and accurately than 3-axis CNC machining does. However, it is difficult to calculate the CL data in 5-axis CNC machining. This paper describes an efficient method to modify and edit the NC code and a data structure for representation of the workpiece produced by 5-axis CNC machining. Wireframe display of tool path and shading display of workpiece are used to represent verification results. Machining errors can be evaluated quantitively using the data structure based on the workpiece data model. The methods are implemented in a program with a IBM-PC and MS-Windows.

• Journal of Hydrogen and New Energy
• /
• v.22 no.3
• /
• pp.409-414
• /
• 2011

To promote the industry of PEMFC, the commercialization of its parts especially bipolar plate is needed. The bipolar plate is one of key parts for PEMFC, which occupies cost portion of 5~8% in the system. To replace the bipolar plate of machined graphite highly costly, the stamped thin matal or the molded carbon composite has been developed. According to the merits and demerits of each material and its forming process, the stamped metallic plate has been considered to the bipolar plate of PEMFC for automotive, and on the other hand, the molded composite plate has been considered to one for building applications. Hankook Tire Co., Ltd. has developed the carbon composite material and the manufacturing process for the bipolar plates. The developed bipolar plates were proved to be fully applicable to PEMFC of building applications in characteristics and performance, and so government strategic project to develop the mass-production technology for bipolar plates was started and is being conducted by the company. Through the government project for obtaining both the commercialization technology and production capacity for the bipolar plates, the price and the performance of domestic PEMFCs are expected to become competitive in international market.

• Safety and Health at Work
• /
• v.3 no.1
• /
• pp.58-66
• /
• 2012

Objectives: The purpose of this study was to review clinical characteristics and working environments of sudden cardiac death (SCD) cases associated with a tire manufacturer in Korea, and review possible occupational risk factors for cardiovascular disease including nanoparticles (ultrafine particles, UFPs). Methods: We reviewed (i) the clinical course of SCD cases and (ii) occupational and non-occupational risk factors including chemicals, the physical work environment, and job characteristics. Results: Possible occupational factors were chemicals, UFPs of rubber fume, a hot environment, shift work, overworking, and noise exposure. The mean diameter of rubber fume (63-73 nm) was (larger than diesel exhaust [12 nm] and outdoor dust [50 nm]). The concentration of carbon disulfide, carbon monoxide and styrene were lower than the limit of detection. Five SCD cases were exposed to shift work and overworking. Most of the cases had several non-occupational factors such as hypertension, overweight and smoking. Conclusion: The diameter of rubber fume was larger than outdoor and the diesel exhaust, the most well known particulate having a causal relationship with cardiovascular disease. The possibility of a causal relation between UFPs of rubber fume and SCD was not supported in this study. However, it is necessary to continue studying the relationship between large sized UFPs and SCD.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.7 s.238
• /
• pp.1005-1012
• /
• 2005

An OHT(Over Head Transportation) vehicle is an example of the industrial monorail vehicle, and it is used in the automobile, semiconductor, LCD manufacturing industries. OHT vehicle is moved by main wheels and guide rollers. The major function of the main wheel is to support and drive the OHT vehicle. The roles of the guide roller is the inhibition of derailment and steering of the OHT vehicle. Since the required vehicle velocity becomes faster and the required load capacity is increased, the durability characteristics of the wheel and roller, which was made of urethane, need to be increased. So it is necessary to estimate the fatigue life cycle of the wheel and roller. In this study, OHT dynamic model was developed by using the multi body dynamic analysis program ADAMS. Wheel and roller are modeled by the 3-D surface contact module. Especially, motor cycle tire mechanics is used in the wheel contact model. The OHT dynamic model can analyze the dynamic characteristic of the OHT vehicle with various driving conditions. And the result was verified by a vehicle traveling test. As a result of this study, the developed model is expected to predict wheel dynamic load time history and makes a contribution to design of a new monorail vehicle.

• Elastomers and Composites
• /
• v.46 no.1
• /
• pp.54-59
• /
• 2011

One of the viscoelastic flow behaviors during profile extrusion is the swelling of extrudate. In this study, die swell of rubber compound in the capillary die have been investigated through experiment and computer simulation. Simplified viscoelastic model and non-linear differential viscoelastic model such as PTT model have been used in the computer simulation. The simulation results have been compared with experimental data. Experiment and simulation have been performed using fluidity tester and commercial CFD code, Polyflow respectively. Die swells predicted by two models showed good agreement with experimental results. Pressure and velocity distribution, and circulation flow at the corner of reservoir have been well predicted by PTT model. Simplified viscoelastic model can not predict circulation flow at the corner of reservoir. However this model has an advantage in computation time compare with full viscoelastic model, PTT model.

• Steel and Composite Structures
• /
• v.51 no.3
• /
• pp.337-349
• /
• 2024

The growing quantity of tires and building trash piling up in landfills poses a serious threat to the stability of the ecosystem. Researchers are exploring ways to reduce and use such byproducts of the construction industry in an effort to promote greener building practices. Thus, using recycled crumb rubber from scrap tires in concrete manufacturing is important for the industry's long-term viability. This study examines the proportion of waste rubber in fiber form, specifically at weight percentages of 5%, 10%, and 15%. Moreover, the study examines the shear behavior of reinforced concrete beams. A total of twelve RC beam specimens, each sized 100 mm by 150 mm by 1000 mm (w × d × L), were constructed and positioned to the test. Various mixtures were designed with different levels of scrap tire rubber content (0%, 5%, 10%, and 15%) and Stirrup Vol. Ratio (2.10, 2.80, and 3.53) in reinforced concrete beams. The findings indicate that the inclusion of scrap rubber in concrete leads to a decrease in both the mechanical characteristics and weight of the material. This is mostly attributed to the lower strength and stiffness of the rubberized concrete. Furthermore, estimations generated by a variety of design codes were examined alongside the obtained data. In order to make a comparison between the estimates provided by the different codes such as ACI 318-14, CEB-FIB and Iranian national building codes, a calculation was done to determine the ratio of the experimental shear strength to the anticipated shear strength for each code.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.2
• /
• pp.947-953
• /
• 2012

In this study we investigated the manufacturing method for the activated carbon using the char from the pyrolysis of waste tire. The physical activation method using the steam in the fixed-bed quartz reactor was used for preparation of activated carbon. The primary experiment parameters are the activation temperature, activation time, heating rate, and the injection quantity of active agent. From the results of pore distribution of activated carbon, the micropore which was made in $850^{\circ}C$ of activation temperature, $5^{\circ}C$/min of heating rate, and 3 hours of activation time was developed in biggest quantity, and mesopore and macropore were developed in the biggest quantity too. The optimum conditions for producing the activated carbon using the pyrolysis residue were $850^{\circ}C$ of activation temperature, 3 hours of activation time, $5^{\circ}C$/min of heating rate, and 3 g $H_2O/char-g{\cdot}hr$ of active agent through this study. The produced activated carbon in these conditions showed that the potentiality of utilization as activated carbon because the BET specific surface area was $517.6m^2/g$ and total pore volume was $0.648cm^3/g$.