• 한국소음진동공학회논문집
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• 제21권10호
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• pp.875-882
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• 2011

In this paper, the finite element analysis model of the mult-axial wheel durability test configuration is created using SAMCEF. Mooney-Rivlin 2nd model is applied to the tire model, and the variation of the air pressure inside the tire is considered. Vertical load, lateral load and camber angle are applied to the simulation model. The tire rotates because of the friction contact with a drum, and reaches its maximum speed of 60 km/h. The dynamics stress results of the simulation and experiment are compared, and the reliability of the simulation model is verified.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.199-207
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• 1999

For the stress and vibration analysis of vehicle component by computer simulation, it is necessary to find the forces acting on the vehicle components due to the road profile undulation. A precise modeling of tires is not easy due to nonlinear effects between tire-ground. In this study, a new method is proposed to regenerate road profiles that preserves the same PSD of wheel with a linear tire model. Using the frequency response function between road-wheel , the digital signal processing method, and DADS program , road profile is regenerated from the computer simulation.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.110-119
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• 1997

Four wheel steering(4WS) systems which can control the lateral and yaw motions of vehicles by steering front and rear wheels simultaneously, have been regarded as effective for improving the stability and handing performance of vehicles. However, since the 4WS systems depend only on the lateral force of tire, they have some limitation due to the nonlinear characteristics of tire related with the saturation phenomenon of lateral force to the slip angle of tire in a near-limit-performance maneuvering range. In this study, in other to evaluate the effect of nonlinear characteristics of tire on the dynamic performance of vehicles, a new concept for driving the cornering stiffness of nonlinear tire by using the "Magic Formula" tire model is proposed. In addition, the nonlinear 4WS vehicle model is constructed based on the proposed cornering stiffness of nonlinear tire. It is noted from simulation that the nonlinear characteristics of tire affect greatly on the 4WS vehicle performance.rformance.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.195-206
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• 1997

In this study, a simulation tool is developed in order to investigate non steadystate cornering performance of 4WD/4WS vehicles. The 4WD/4WS vehicles are modeled as a 8-th order dynamic system which includes complex non-linear vehicle dynamics and tire models. The vehicle models are constructed into a modulated simulation tool and are utilized for analyzing cornering performance such as combined braking and steering, cornering on the icy read and $\mu$-split braking, The whole analysis is done with the simulation tool which consists of a number of subsystems and offers graphic environment. Simulation results show that this tool is useful and cost-effective in the dynamic analysis of the combustion-engine vehicles as well as electrically driven vehicles.

• International Journal of Automotive Technology
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• 제1권1호
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• pp.26-34
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• 2000

The new numerical procedure for hydroplaning has been developed by considering the following three important factors; fluid/structure interaction, tire rolling, and practical tread pattern. The tire was analyzed by FEM with Lagrangian formulation and the fluid is analyzed by FVM with Eulerian formulation. Since the tire and the fluid are modeled separately and their coupling is automatically computed by the coupling element, the fluid/structure interaction of the complex geometry such as the tire with the tread pattern can be analyzed practically. We verified the predictability of the hydroplaning simulation in the different parameters such as the water flow, the velocity dependence of hydroplaning, and the effect of the tread pattern on hydroplaning. In order to predict the streamline in the contact patch, the procedure of the global-local analysis was developed. Since the streamline could be predicted by this technology, we could develop the new pattern in a short period based on the principle; "make the stream line smooth".

• Agricultural and Biosystems Engineering
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• 제1권1호
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• pp.1-6
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• 2000

Using the modified DEM (Distinct Element Model), which we proposed, the effect of cross section of tire lug on the tire performance was simulated. Though the DEM has an advantage over the FEM when it is applied to simulate the behavior of discrete assembly of particles such as soil, there was still a problem in the case of conventional DEM, that the simulated movement of particles was too free. We constructed a new mechanical model (modified DEM) which can take account of the effect of adhesion between particles. It is shown that the soil deformation is simulated by the modified DEM better than the conventional DEM. Comparing the simulated soil reaction to the tire lug with the experimental results, the adequate DEM parameters were found. It is also indicated possible to find the effect of lug cross section shape on the tractive performance of tire by the DEM simulation.

• 한국자동차공학회논문집
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• 제24권3호
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• pp.310-318
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• 2016

The demands for vehicle safety systems such as ABS and ESC have been increased. Accurate vehicle state estimation is required to realized the abovementioned systems and tire-friction coefficient is crucial information. Estimation of lateral tire-road friction coefficient using pneumatic trail information is mainly dealt in this paper. Pneumatic trail shows unique characteristics according to the wheel side slip angle and these property is highly sensitive to vehicle lateral motion. The proposed algorithm minimizes the use of conventional tire models such as magic formula, brushed tire model and Dugoff tire model. The pure side slip maneuver, which means no longitudinal dynamics, is assumed to achieve the ultimate goal of this paper. A simulation verification using Carsim and Simulink is performed and the results show the feasibility of the proposed algorithms.

• 제어로봇시스템학회논문지
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• 제16권7호
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• pp.632-638
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• 2010

This paper presents an optimum tire force distribution method for 6WD/6WS(6-Wheel-Drive and 6-Wheel-Steering) electric vehicles. Using an independent steering and driving system, the performance of 6WD/6WS vehicles can be improved, as, for example, with respect to their maneuverability under low speed and their stability at high speed. Therefore, there should be a control strategy for finding the optimum tire forces that satisfy the driver's command and minimize energy consumption. From the driver's commands (steering angle and accelerator/brake pedal stroke), the desired yaw moment, the desired lateral force, and the desired longitudinal force were obtained. These three values were distributed to each wheel as the torque and the steering angle, based on the optimum tire force distribution method. The optimum tire force distribution method finds the longitudinal/lateral tire forces of each wheel that minimize the cost function, which is the sum of the normalized tire forces. Next, the longitudinal/lateral tire forces of each wheel are converted into the reference torque inputs and the steering wheel angle inputs. The proposed method was tested through a simulation, and its effectiveness was verified.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.149-159
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• 2005

A full nonlinear finite element P185/70Rl4 passenger car radial-ply tire model was developed and run on a 1.7-meter-diameter spinning test drum/cleat model at a constant speed of 50 km/h in order to investigate the tire transient response characteristics, i.e. the tire in-plane free vibration modes transmissibility. The virtual tire/drum finite element model was constructed and tested using the nonlinear finite element analysis software, PAM-SHOCK, a nonlinear finite element analysis code. The tire model was constructed in extreme detail with three-dimensional solid, layered membrane, and beam finite elements, incorporating over 18,000 nodes and 24 different types of materials. The reaction forces of the tire axle in vertical (Z axis) and longitudinal (X axis) directions were recorded when the tire rolled over a cleat on the drum, and then the FFT algorithm was applied to examine the transient response information in the frequency domain. The result showed that this PI 85/70Rl4 tire has clear peaks of 84 and 45 Hz transmissibility in the vertical and longitudinal directions. This result was validated against more than 10 previous studies by either theoretical or experimental approaches and showed excellent agreement. The tire's post-impact response was also investigated to verify the numerical convergence and computational stability of this FEA tire model and simulation strategy, the extraordinarily stable scenario was confirmed. The tire in-plane free vibration modes transmissibility was successfully detected. This approach was never before attempted in investigations of tire in-plane free vibration modes transmission phenomena; this work is believed to be the first of its kind.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.684-689
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• 2000

In this paper, the equations of motion about vehicle, powertrain and brake system were derived. The vehicle has eight degrees of freedom with nonlinear tire model and the powertrain has two degrees of freedom containing engine, torque converter and four speed automatic transmission. The brake system has two states about front and rear brake line pressures. The transient tire model with first order time lag is also subjoined for low speed or stop-and-go simulation. The modeling was derived considering two points - the fidelity and the simplicity. The simulation using this model is similar with real vehicle dynamic behavior and the model is made as simple as possible far fast simulation. It is validated that the derived vehicle model can be applicable to the real time simulation.