• Journal of Mechanical Science and Technology
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• v.20 no.9
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• pp.1399-1409
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• 2006

An improved friction model was proposed with consideration of the effect of the sliding speed, the contact pressure and the temperature, and it was implemented into a user subroutine of a commercial FEM code, ABAQUS/Explicit. Then, a smooth tire was simulated for free rolling, driving, braking and cornering situations using the improved friction model and the Coulomb friction model, and the effect of the friction models on the slip, the frictional energy distribution and the cornering force and moment was analyzed. For the free rolling, the driving and the braking situations, the improved friction model and the Coulomb friction model resulted in similar profiles of the slip and the frictional energy distributions although the magnitudes were different. The slips obtained from the simulations were in a good correlation with experimental data. For the cornering situation, the Coulomb friction model with the coefficient of friction of 1 or 2 resulted in lower or higher cornering forces and moments than experimental data. In addition, in contrast to experimental data it did not result in a maximum cornering force and a decrease of the cornering moment for the increase of the speed. However, the improved friction model resulted in similar cornering forces and moments to experimental data, and it resulted in a maximum cornering force and a decrease of the cornering moment for the increase of the speed, showing a good correlation with experimental data.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.126-131
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• 2012

Tire force is one of important parameters which determine vehicle dynamics. However, it is hard to measure tire force directly through sensors. Not only the sensor is expensive but also installation of sensors on harsh environments is difficult. Therefore, estimation algorithms based on vehicle dynamic models are introduced to estimate the tire forces indirectly. In this paper, an estimation system for estimating lateral force and states is suggested. The state-space equation is constructed based on the 3-DOF bicycle model. Extended Kalman Filter, Unscented Kalman Filter and Ensemble Kalman Filter are used for estimating states on the nonlinear system. Performance of each algorithm is evaluated in terms of RMSE (Root Mean Square Error) and maximum error.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1667-1675
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• 2003

This paper has considered the calculation of lateral stiffness of radial tire's sidewall, which consists of cord stiffness and rubber sheet stiffness, by using the material constants of rubber compounds of tire. We have suggested and illustrated how to calculate the rubber sheet lateral stiffness by considering the following aspects. First, the rubber sheet consists of various kinds of rubber compounds with different thickness along the sidewall in the radial direction. Secondly, equivalent Young's modulus of the rubber sheet can be calculated by using available experimental data of rubber compounds. The present method enables us to divide the calculation domain as many as we want, which can reduce numerical error in the calculation of geometrical and mechanical properties. We have illustrated the calculation by using the data of the radial tire for passenger car of P205/60R15.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.104-112
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• 2006

The influence of tire belt angle on the Plysteer Residual Aligning Torque(PRAT) and the cornering stiffness by the FEM has been studied. The PRAT is a performance factor of the tire about vehicle pull, and the cornering stiffness has relation to vehicle steering response of outdoor test. To validate FE model for analysis, simulation data for both the static stiffness(vertical, lateral) and the PRAT have been compared with the experimental data. In addition to the characteristics of the PRAT and the cornering stiffness due to the tire belt angle, rolling and cornering contact characteristics have been studied. The tendency of the PRAT and the cornering stiffness due to the belt angle can be used as a guide line for the tire design in relation to vehicle pull and vehicle steering response.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.498-503
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• 2006

Adsorption features of $Cd^{2+}$ on waste tire particles have been investigated for the purpose of enhanced wastes recycling along with the development of an economic process for wastewater treatment. The isoelectric point of waste tire particles was found to be ca. pH 7 and the adsorbed amount of $Cd^{2+}$ was increased with pH under experimental conditions. The variation of the adsorption behavior of $Cd^{2+}$ with pH was well explained by the change of the electrokinetic potential of waste tire particles according to the pH. Adsorption of $Cd^{2+}$ was observed to reach its equilibrium within 45 minutes after the adsorption started under experimental conditions and followed the Freundlich model well. Kinetic analysis showed that the adsorption reaction of $Cd^{2+}$ was second order and thermodynamic estimation substantiated the endothermic behavior of $Cd^{2+}$ adsorption. As the amount of adsorbent increased, more adsorption of $Cd^{2+}$ was accomplished and the adsorption capacity of adsorbent was found to be enhanced by its pre-treatment with NaOH. Also, the adsorption of adsorbate was promoted as the ionic strength of wastewater was increased.

• Korean Business Review
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• v.22 no.1
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• pp.27-44
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• 2009

This paper compares the accounting standards for stock option of Japan and Korea. Especially, tire setting process of accounting standards for stock option, accounting methods and disclosures for stock option in two countries are analyzed. The results provide that two countries shaw different characteristics in accounting standards for stock option. First, in Japan, acquired services are reported as compensation costs and capital adjustments. On the other hand, in Korea, in case of cash-settled share- based payment transactions, acquired services are reported as compensation costs and capital adjustments, but in case of equity-settled share- based payment transactions, acquired services are reported as compensation costs and debt. Second, when tire stock option rights are abandoned, they are reported as extraordinary items in Japan and are reported as other surplus in Korea. Third, though both countries do not choose specific stock option pricing model, Japan prefers Black-Sholes Model and Korea regards binomial model as proper model.

• Computers and Concrete
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• v.26 no.6
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• pp.467-482
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• 2020

This research focused on analyzing the post-fire behavior of high-performance concrete-filled steel tube (CFST) columns, with the concrete containing tire rubber and steel fibers, under axial compressive loading. The finite element (FE) modeling of such heated columns containing recycled aggregate is a branch of this field which has not received the proper attention of researchers. Better understanding the post-fire behavior of these columns by measuring their residual strength and deformation is critical for achieving the minimum repair level required for structures damaged in the fire. Therefore, to develop this model, 19 groups of confined and unconfined specimens with the variables including the volume ratio of steel fibers, tire rubber content, diameter-to-thickness (D/t) ratio of the steel tube, and exposure temperature were considered. The ABAQUS software was employed to model the tested specimens so that the accurate behavior of the FE-modeled specimens could be examined under test conditions. To achieve desirable results for the modeling of the specimens, in addition to the novel procedure described in this research, the modified versions of models presented by previous researchers were also utilized. After the completion of modeling, the load-axial strain and load-lateral strain relationships, ultimate strength, and failure mode of the modeled CFST specimens were evaluated against the test data, through which the satisfactory accuracy of this modeling procedure was established. Afterward, using a parametric study, the effect of factors such as the concrete core strength at different temperatures and the D/t ratio on the behavior of the CFST columns was explored. Finally, the compressive strength values obtained from the FE model were compared with the corresponding values predicted by various codes, the results of which indicated that most codes were conservative in terms of these predictions.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.459-470
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• 2015

In this study, we have developed a retirement coaching model for effective retirement planning by applying systematic conversation of the coaching technique. A draft of the retirement coaching model was complemented by the validity verification of experts. The retirement coaching model can be summarized as follows. The first step, rapport and empowerment(RE), consists of sharing the image of a happy retirement after establishing a rapport between the coach and the people wanting to prepare for retirement. The second step, target establishment(T), consists of setting the theme and goals of the conversation. The third step, identification(I), consists of developing a retirement plan for achieving the established goals. The fourth step, realization(R), consists of establishing a concrete schedule and a method of retirement planning. The fifth step, evaluation(E), consists of sharing impressions during coaching sessions, which facilitates future action plans.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.41-48
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• 2011

In order to assess the reliability of the Tire Pressure Sensor for automobiles, accelerated life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows; i) the main failure mechanism is degradation failure that is, PCB destruction and battery Discharge by high temperature. ii) the life distribution of the Tire Pressure Sensor fitted well to Weibull life distribution and the accelerated life model of that is fitted well to Arrhenius model. iii) at the result of the life distribution, accelerated life test method is developed

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.314.1-314
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• 2002

It has been shown that the vibrational response of a tire can be represented by a set of decaying waves, each associated with a particular cross-sectional shapes, in the region near the contact patch. Thus, it can be concluded that tires can be effectively modeled as lossy waveguides. It has also been shown that the sound radiation from tires is mainly from the region close to contact patch. (omitted)