• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.271-276
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• 2011

The working conditions of construction equipments such as excavators, wheel loaders and haulers are very tough and severe in fact. To design main components of construction equipment under the severe environment, it's important for engineers to consider design for vibration durability point of view at the early stage of product development process. Radiator as a cooling unit of construction equipment is one of critical components to apply design for vibration. We present a design for vibration process and methodology on the radiator system in construction equipment industries. From the natural frequency and the random vibration analysis based on field vibration test data, we could find current status of radiator layout design to develop and made best layout specification of radiator design to decide for product development process at the early stage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.240-243
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• 2005

A design procedure using spatial Fourier transform is presented for a structural-acoustic coupled radiator that can emit sound in the desired direction with high power and low side lobe level. The design procedure consists of three steps. Firstly, the structural-acoustic coupled radiator is chosen to obtain strong coupling between structural vibration and acoustic pressure. The radiator is composed by two spaces which are separated by a wall. Spaces can be categorized as reverberant finite space and unbounded semi-infinite space, and the wall are composed of two plates and an opening. The velocities on the wall are predicted. Secondly, directivity and energy distribution of radiator are predicted in wave number domain using spatial Fourier transform. Finally, optimal design variables are calculated using a dual optimal algorithm. Its computational example is presented including the directivity and resulting pressure distribution using proposed procedure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.225-231
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• 2005

This paper presents a design method for the structural-acoustic coupled radiator that can emit sound in the desired direction. A coupled system that has a finite space and a semi-infinite space separated by two flexible walls and an opening is considered. An objective function is selected to maximize radiation power on a main axis and minimize a side lobe level. To get initial values, prediction of a pressure distribution on field points and radiation pattern of the structural-acoustic coupling system is shown at a coupled-resonant frequency. Three different optimization methods are adapted to design the coupled radiator. Pressure and intensity distribution of the designed radiator is presented.

• Journal of KSNVE
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• v.8 no.2
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• pp.274-282
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• 1998

A systematic procedure for designing a direct-radiator-type loudspeaker has been developed, based on the numerical vibro-acoustic analysis and the Taguchi method. The finite-element model of the speaker cone has been used to calculated the vibration response of the cone excited by the voice coil. The vibration displacement of the speaker cone has been converted into the vibration velocity and used as a boundary condition for the acoustic analysis. The acoustic frequency characteristics of the loudspeaker have been calculated by the boundary element method. The numerical results have been verified by the experiments carried out in an anechoic chamber. Some design parameters have been selected by using the Taguchi method, and the variations of the acoustic characteristics due to the changes of the parameter values have been examined using the numerical model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.847-847
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• 2004

Automobile cooling fans are operated with a radiator module. To design low noise, high performance cooling fan, radiator resistance should be considered in the design process. The system (radiator) resistance reduces axial velocity and increases effective angle of attack. This increasing effective angle of attack mechanism causes blade stall, performance decrease and noise increase. In this paper, To analyze fan performance, freewake and 3D CFD calculations are used To design high performance fan with consideration of system resistance, optimal twist concept is applied through momentum and blade element theory. To predict fan noise, empirical formula and acoustic analogy methods are used.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.431-432
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.153-159
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• 1996

The acoustic characteristics of a direct radiator type loudspeaker has been studied in this paper. The vibration displacement of the speaker cone paper obtained by the finite element analysis has been converted into the vibration velocity and used as a boundary condition for the acoustic analysis. The frequency characteristics and the sound pressure distribution of the loudspeaker resulted from the radiation of the cone vibration have been calculated by the boundary element analysis. The numerical results have been verified by experiments carried out in an anechoic chamber. The variations of the acoustic characteristics due to the changes of some design parameters have been examined using the numerical model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.568-574
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• 1998

A systematic procedure for designing a direct-radiator-type loudspeaker has been developed, based on a numerical vibro-acoustic analysis and the Taguchi method. The finite-element model of the speaker cone has been used to calculate the vibration response of the cone excited by the voice coil. The vibration response of the speaker cone has been used as a boundary condition for the acoustic analysis, and the acoustic frequency characteristics of the loudspeaker have been calculated by the boundary element method. The numerical model has been confirmed by comparing the numerical results with experimental ones obtained in an anechoic chamber. Some design parameters contributing dominantly to the acoustic characteristics have been selected by using the Taguchi method, and the variations of the acoustic characteristics due to the changes of the parameter values have been examined using the numerical model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.10
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• pp.1742-1756
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• 1997

The acoustic characteristics of a direct radiator type loudspeaker has been studied in this paper. The natural modes of the speaker cone vibration analyzed numerically by the finite element method have been verified by comparing them with experimental results. The so-ap-proved finite-element model has been used to calculate the vibration response of the cone excited by the voice coil. The vibration displacement of the speaker cone paper has been converted into the vibration velocity and used as a boundary condition for the acoustic analysis. The frequency characteristics, directivity, and sound pressure distribution of the loudspeaker have been calculated by the boundary element method. The numerical results have been verified by the experiments carried out in an anechoic chamber. The variations of the acoustic characteristics due to the changes of some design parameter values can be examined using the numerical model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.143-149
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• 2009

Recently, according to the tendency to the more comfortable automobile, the improvement of performance of the cooling fan is required. The performance of cooling fan is affected by many peripheral parts, such as radiator, condenser, engine block and etc. Therefore, it is important to consider the effect of peripheral components on the fan performance in design and analysis stages. In this paper, the performance of automobile cooling fan is investigated experimentally by using the large capacity fan tester based on the ASHRAE and the AMCA standards. In particular, the various spacing between cooling fan and engine block are considered to obtain the effect of engine block. An empirical relation between the fan flow rate and the spacing was proposed.