• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.86-93
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• 2006

This study is concerned with the investigation of characteristics of an AMT (Automated Manual Transmission) which are composed of clutch part and transmission part. When a shilling signal is received from the controller, the clutch is disengaged first, and shifting action including selecting action is followed, and then the clutch is engaged last. The characteristics of transmission shifting response are affected by various parameters of clutch and transmission control elements. Analytical results are in fair agreement with experimental results. It is found that the operating pressure level is the most important for the response of AMT characteristics, and that the other parameters such as natural frequency and damping ratio of the control valve are less important.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.854-859
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• 2001

An eigenvalue analysis of a tunable micro-mechanical actuator is presented. The actuator is modeled as a continuum structure. The eigenvalue modified by the tuning voltage is computed through the linearization of the relation between the electrostatic force and the displacement at the equilibrium. A staggered algorithm is employed to perform the coupled analysis of the electrostatic and elastic fields. The stiffness matrix of the actuator is modified at this equilibrium state. The displacement field is perturbed using an eigenmode profile of the actuator. The configuration change of the actuator due to perturbation modifies the electrostatic field and thus the electrostatic force. The equivalent stiffness matrix corresponding to the perturbation and the change in the electrostatic force is then added to stiffness matrix in order to explain natural frequency shifting. The numerical examples are presented and compared with the experiments in the literatures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.601-606
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• 1993

The natural frequency measurement of passenger car tire under the load and rotation are studied. In order to obtain theoretical natural frequency and mode shape, the plane vibration of a tire is modeled to that of circular beam. By using the Tickling method based on Hamilton's principle, theoretical results are determined by considering tension force due to tire inflation pressure, rotational velocity and tangential, radial stiffness. Modal parameters varying the inflation pressure, load, rotational velocity are determined experimentally by using frequency response function method. The results show that experimental conditions are parameter for shifting of natural frequency.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.137-144
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• 1995

The purpose of this study is to obtain a foundation data for chassis design and road noise reduction of automobiles. Using the combination of the automobile, radial tires and instrumentation equipment, experimental investigation was carried out to examine the characteris- tics of the structural vibration of tire as the key to obtaining the effective parameters for reducing road noise. From the results of this studies it has been confirmed that the specific ranges of natural frequency of tire exciting the suspension and chassis system. And the tire, axle and chassis natural frequency of automobile govern the road noise. Results show that material properties of tire and experimental condition are major parameter for shifting of tire natural frequency. These results would be utilized as basic materials for the design of chassis design with papametric study, which enables a designer of an automobile to foresee the influence of the various design factors or operating conditions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.4 s.97
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• pp.375-381
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• 2005

The purpose of this study is to obtain a foundation data for chassis design and road noise reduction of automobiles. Using the combination of the automobile, radial tires and instrumentation equipment, experimental investigation were carried out to examine the characteristics of the structural vibration of tire as the key to obtaining the effective parameters for reducing road noise. From the results of experimental studies it has been confirmed that the existence of important frequency ranges, which were attributable to the suspension and chassis system. The tire, axle and chassis natural frequency of automobile govern the road noise. Results that material property of tire and experimental condition are parameter for shifting of tire natural frequency, which enables a designer of an automobile to foresee the influence of the various design factors on the road noise.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.223-228
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• 1996

The frequency of the brake squeal noise can be changed during braking, and this frequency shifting is due to variation of braking deceleration rate. The natural frequency of the brake system also shifted according to deceleration rate. It makes difficult to treat this problem. This paper shows an experimental study on the brake squeal noise having main frequencies of about 450~500Hz. And it shows how to improve the brake squeal noise problem.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.898-902
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• 2006

The motion of a system composed of a plate, constant springs and varying dampers is considered when the system is subject to harmonic force. Letting the frequencies of harmonic force and damper variation ${\Large f}_1\;and\;{\Large f}_2$ respectively, the displacement at the center of the plate has the strongest component at frequency ${\Large f}_1$. The angular displacement of the plate has strong components at ${\Large f}_1-{\Large f}_2$ and the natural frequency of the rotational mode of the system. If these two frequencies coincide, the plate oscillates with almost single frequency and a large amplitude. Part of these simulation results are proved analytically.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.9 s.114
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• pp.958-963
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• 2006

The motion of a system composed of a plate, constant springs and varying dampers is considered when the system is subject to harmonic force. Letting the frequencies of harmonic force and damper variation $f_1\;and\;f_2$, respectively, the displacement at the center of the plate has the strongest component at frequency $f_1$. The angular displacement of the plate has strong components at $f_1-f_2$ and the natural frequency of the rotational mode of the system. If these two frequencies coincide, the plate oscillates with almost single frequency and a large amplitude. These results can be applied to development of a moment shaker with low frequencies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.81-85
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• 2006

The motion of a system composed of a plate, constant springs and varying dampers is considered when the system is subject to harmonic force. Letting the frequencies of harmonic force and damper variation ${\Large f}_1\;and\;{\Large f}_2$, respectively, the displacement at the center of the plate has the strongest component at frequency ${\Large f}_1$. The angular displacement of the plate has strong components at ${\Large f}_1-{\Large f}_2$, and the natural frequency of the rotational mode of the system. If these two frequencies coincide, the plate oscillates with almost single frequency and a large amplitude. These results can be applied to development of a moment shatter with low frequencies.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.2
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• pp.76-83
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• 1993

The vibration characteristics of radial tire are studied. In order to obtain theoretical natural frequency and mode shape, the plane vibration of a tire is modeled to that of circular beam. By using the Tielking method based on Hamilton's principle, theoretical results are determined by considering tension force due to tire inflation pressure, rotational velocity and tangential, radial stiffness. Modal parameters varying the inflation pressure are determined experimentally by using the transfer function method. Results show that material property and wear are parameter for shifting of natural frequency and damping.