• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.148-153
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• 1998

A resonance is the one of major reasons of vibration problems occurred in industrial fields. To reduce vibration level due to resonance, structure reinforcements or change of the dynamic characteristics is generally applied. In this paper, the troublesome vibration levels of the motor shaft and auxiliary condensate pump are reduced by avoiding resonance.

• Journal of KSNVE
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• v.9 no.5
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• pp.936-942
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• 1999

Unstable torsional vibration on the marine ship's propulsion shafting system with diesel engine occurred due to a slippage of multi-friction clutch which was installed between increasing gear and shaft generator. In this paper, the mechanism of this vibration was verified via torsional, whirling, axial and structural vibration measurements of shafting system and noise measurement of gear box. And it was also identified by the theoretical analysis method.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.72-79
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• 2008

To meet demand of big capacity and high speed rotation for washing machine, more stress from bending and twisting are complexly loaded onto the shaft supporting the horizontal drum, causing problems in fracture strength and fatigue life. Shafting system is mainly divided into flange and shaft. Shaft and flange connected by inserting shaft serration into flange on the process of die casting. When the system is operating, the gap is formed between serration and flange. But, Serration has various design factors and the optimal values can't be easily determined. Using a design of experiment (DOE) based on the FEM (Finite Element Method), this study was performed investigating the interaction effect between the various design factors as well as the main effect of the each design factor under bending, twist and vibration and proposed optimum design using box-behnken method among response surface derived from regression equation of simulation-based DOE.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.859-864
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• 2008

The dynamic interaction between the moving mass and the rotating Timoshenko shaft is investigated. The moving speed of the mass is presented by a constraint equation related to the rotating speed of the shaft. The dimensionless equations of motion for the rotating shaft with a moving mass by using the Timoshenko's beam theory. The dynamic responses of this system are studied. influences of dimensionless parameters such as the rotating speed ratio. the Rayleigh coefficient and the dimensionless axial force are discussed on the transient response and the maximum deflection of the moving system.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.307-313
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• 2022

The importance of engine vibration reduction is increasing as the vehicle interior noise becomes more serious due to higher output and lighten weight trends. Recently, the balance shaft attachment has been proposed as a representative method for the engine vibration reduction. The balance shaft is a device that cancels the vibrations generated in the reciprocating motion of the piston and the conrod by using an arbitrary eccentric mass, and can improve fuel efficiency and ride comfort at the same time. This paper proposes the unbalance amount and shape of the balance shaft to induce and offset the inertia force generated by the engine structure. The proposed two-shaped balance shaft was implemented as an ADAMS multi-body dynamics model, and the reduction of the inertial force in the actual behavior was confirmed through dynamic simulation.

• Composites Research
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• v.34 no.6
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• pp.380-386
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• 2021

This paper aims to improve the critical speed of power-take-off (PTO) shafts by using carbon fiber reinforced plastics (CFRPs). The PTO shaft was designed with titanium-CFRPs hybrid structure in order to compensate the low shear strength of CFRPs. Based on the requirements for PTO shafts, the dimensions of PTO shafts were determined through a parametric study. To evaluate the performance of the PTO shaft, a vibration test, a static torsion test, and a torsion durability test were performed. In the vibration test, the critical speed of PTO shafts was 20570 rpm, which was 7.5% higher than that of titanium shafts. Additionally, it was confirmed that the maximum allowable torque of the PTO shaft was 2300 N·m. Finally, under repeated load in the range of 11.3 to 113 N·m, the fatigue failure in the PTO shaft did not occur up to 10⁶ cycles.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.504-506
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• 1996

In the industrial motor drive systems, a shaft torsional vibration is often generated when a motor and a load are connected with a flexible shaft. This paper treats the vibration suppression control of this system. The resonance ratio control is proposed for suppressing the torsional vibration. In this paper, first, the optimal resonance ratio is sellected and the controller to the resonance ratio controlled outward plant is designed based on $H_{\infty}$ control theory. Secondly, the two-degree-of-freedom controller, which includes the above $H_{\infty}$ controller, is designed in order to improve the tracking characteristics for the commanded speed. The control performances are examined by the computer simulations and it is clarified that the proposed speed control system is useful for two-mass system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.1
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• pp.46-52
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• 2012

Since the engine and reduction gear in a naval vessel are usually supported by the mounting system separately, the misalignment between the input shaft of the reduction gear and the output shaft of the engine should occur caused by ship motion. In this study, this misalignment is estimated from the linear static analysis assuming that the phase of movements of the engine and reduction gear at low frequency range is same and the dynamic effect is not affect to them. Through comparing the relative displacement of the engine and reduction gear calculated from linear static analysis to that from dynamic analysis as well as experiment, the assumption in this study could be verified.

• 유체기계공업학회:학술대회논문집
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• 1998.12a
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• pp.159-165
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• 1998

Bearing design of turbo type geared centrifugal air compressor for low vibration level has been studied. The Transfer Matrix Method was used in this paper to analyze the air-compressor consisting of impellers, multi-stage geared rotors, and oil-film hearings. We have to consider this air-compressor as multi-geared rotating system, because characteristics of rotor-bearing system are different from conventional characteristics of non-rotating system. From the view point of Rotordynamics, the stiffness and damping coefficient of oil-film bearing in case of compressor system are more sensitive than other design parameters such as shaft length, shaft diameter and the weight of impellers, etc. Therefore, the stiffness and damping coefficients on each bearing were considered as design parameters. As the result of this study, turbo type air compressor with low vibration level can be achieved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.233-237
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• 2014

In this paper, the finite element modeling of the RK4 rotor kit system (RK4) and then frequency analysis and transient analysis, and was compared with the actual experimental results. RK4 manufactured by General Electric for the purpose of education and research. It is composed of two shaft, Two shaft is connected using a flexible coupling, one disk is mounted. The analytical model is modeled by using the ANSYS finite element analysis program commercially available. Based on impact hammer test results, material properties and the stiffness of the bearing and coupling was tuned. Considering the operating conditions and the vibration response of the analytical model were compared with experimental results.