• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.358-363
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• 1997

The Operational Deflection Shape designates the motion pattern by which a structure vibrates under a specific operating condition. Modal Analysis is usually tested under test bench, but Operational Deflection Shape can be measured directly under real operating condition. It provide useful information for trouble-shooting and aid understanding and evaluation of the absolute dynamic behaviour of a machine or component. In this paper, It is analysed Excavator Upper Frame using Operating Deflection Shape.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.2
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• pp.190-198
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• 2006

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.124-125
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.476-481
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• 2013

Transfer path analysis(TPA) and operational deflection shape(ODS) have been widely utilized to analyze the characteristics of noise. TPA enables to decompose a noise into air-borne and structure-borne noises then estimate the path contribution of noise. ODS enables to analyze a moving shape and direction of interest components at a particular frequency. In this paper, TPA and ODS are applied to transfer paths of air-conditioner booming noise in a vehicle to reduce noise level, then a fixture is mounted it's path for distributing the high portion path contribution to the low portion path contribution. Through this experiment, the reduction of sound pressure level in air-conditioner booming noise is observed. Thereafter, TPA is again employed to verify the results of contribution.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.556-563
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• 2010

The main noise source of the rotary compressor for air conditioner was analyzed by using the measurement of sound intensity, modal analysis and operational deflection shape(ODS) analysis. In this study, the key noise source of rotary compressor was an accumulator, and noise was sharply increased due to the accumulator's resonance which has a big contribution to the noise. To reduce the excessive noise generated from accumulator, structural modification through ODS analysis were applied. Its validation was conducted by the measurement of noise and vibration on the accumulator's surface. The total noise was significantly reduced by 4.2dB(A).

• International Journal of Automotive Technology
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• v.8 no.1
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• pp.75-82
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• 2007

This paper presents practical work on the reduction of gear whine noise. In order to identify the source of the gear whine noise, transfer paths are searched and analyzed by operational deflection shape analysis and experimental modal analysis. It was found that gear whine noise has an air-borne noise path instead of structure-borne noise path. The main sources of air-borne noise were the two global modes caused by the resonance of an axle system. These modes created a vibro-acoustic noise problem. Vibro-acoustic noise can be reduced by controlling the vibration of the noise source. The vibration of noise source is controlled by the modification of structure to avoid the resonance or to reduce the excitation force. In the study, the excitation force of the axle system is attenuated by changing the tooth profile of the hypoid gear. The modification of the tooth profile yields a reduction of transmission error, which is correlated to the gear whine noise. Finally, whine noise is reduced by 10 dBA.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.210-215
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• 2001

CD-ROM Drives Rotating high speed as 10000 rpm cause serious noise and vibration problems. At the high speed, dominant noise is Air Borne Noise produced from high-speed airflow and Structure Borne Noise produced from structural vibration. In this research, vibration and sound characteristics in CD-ROM Drive were studied by the use of experimental analysis and computational simulation. Sound intensity techniques and ODS(Operational Deflection Shape) techniques are applied to identify the acoustic noise source of CD-ROM drive. And Computational simulation using SYSNOISE is conducted for describing the noise behavior.

• Journal of Biosystems Engineering
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• v.29 no.2
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• pp.101-108
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• 2004

The objectives of this study were to determine the natural frequency of a walking-type cultivator's handle using a modal analysis, to determine whether or not the handle resonates with forcing frequency induced by its engine, and to determine a method to reduce the handle vibration using a technique of the operational deflection shapes(ODS). Results of the study are as follows: The natural frequencies of the handle up to third harmonics were found to be 20.4, 22.5 and 92.1 Hz in the vertical direction and 14.9, 93, and 132 Hz in the horizontal direction. It was found that the handle does not resonate with the forcing frequency of the engine, which is 52 Hz. The operational deflection shape analysis revealed the deflected shapes of the handle in the vertical and horizontal directions and suggested that the handle vibration can be reduced by adding some mass to the place where the largest deflection occurs. Attaching of 1.1 kg mass adjacent to the largely deflected area resulted in reductions of vibration from 9.45 to 8.03 m/s$^2$ in x-axis direction from 3.89 to 3.16 m/s$^2$ in y-axis direction and from 7.89 to 3.09 m/s$^2$ in z-axis direction, which are respectively 15, 19 and 61% reductions. The total vibration level was reduced by 29%, indicating that mass-adding method by the ODS is very effective for reducing the handle vibrations of the cultivators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.232-237
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• 2006

Operation deflection shapes(ODS) is defined as a motion of structure at particular frequency. The ODS is eligible to show any types of structural motions while the modes supply solutions only to linear and stationary motion. The principal vibration source of an auto teller machine(ATM) case was occurred due to resonance which was found by modal analysis. To reduce the vibration of ATM case, the motion of the case was visualized using ODS analysis, which can suggest how to modify the structure. As a result the vibration of the ATM case was greatly reduced with a stiffening bar between the opposite plates.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.431-434
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• 2005

Generally, noise in a reciprocating compressor is attributed to the driving force of a pump. However, close examination shows that the noise heard by customers finally results from radiation of a shell in a compressor, the noise caused by both transmission through a shell and resonance with the natural frequency of a shell. Therefore, the peak frequencies contributing to the overall level of a compressor' noise are closely concerned with vibration of a shell. That's why radiated noise by vibration can be reduced by changing the mode of a shell and by shifting the peak frequencies to other ranges, which are not globally related with the overall noise level. In this paper, the main peak frequencies are analyzed to reduce the radiated noise of a shell, and the vibration characteristics of a shell are examined through Frequency Response Function and Finite Element Analysis. Moreover, the Operational Deflection Shape for a shell is measured with consideration of real driving force of a pump. Finally, the optimum position on a shell, closely related to the main peak frequencies, is found, and the overall noise level caused by radiated noise of a shell is noticeably reduced by mass or stiffness modification of the position.