• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1473-1478
• /
• 2000

Severe fork-lift truck noise is annoying to an operator as well as one of the noise pollution elements. This paper presents the noise contribution analysis of a cabin type fork-lift truck to identify the major sources and its usage to reduce the interior noise level. The methodologies for this work are sound field analysis, sound intensity test, insertion loss test of duct system and etc. An effective method to suppress interior noise level of fork-lift truck and design guides are suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1183-1186
• /
• 2007

The low frequency noise, including infra-sound is known to affect human physiology and psychology. Guidelines and measurement method of low frequency noise has been introduced in several countries in order to evaluate low frequency noise. In this work, low frequency noise characteristics of dump truck was investigated in terms of the noise level and spectrum. The interior sound pressure level of the dump truck was between 60 and 105 dB in the frequency range of $1{\sim}250$ Hz.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.05a
• /
• pp.855-860
• /
• 2001

In this study, the improvement work to reduce the steering wheel vibration of a forklift truck is performed. The forklift truck newly developed possesses a trans-axle type power train to achieve a compact and low-price design. The forklift truck is directly subjected to a high-level engine vibration through hard mounted trans-axle housing. The engine vibration shakes the whole system of the forklift truck, and then a high level local vibration of steering wheel could not be avoided. As the results, the vibration source and path mechanisms are experimentally identified and then an improvement design is proposed to minimize the steering wheel vibration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.912-918
• /
• 2004

Main vibration problems of a transaxle type forklift truck are caused by the resonance of engine excitation force and natural mode shade of major components such as engine-mount system, mast, and main frame. But, it is well known that the reduction of vibration is very difficult because of the limitation of structural modifications. In this paper, the vibration characteristics of engine-mast system including engine mount were firstly identified by the experimental and simplified numerical methods. And also, the free and forced vibration characteristics of a whole forklift truck were surveyed with modal test and ODS(operation deflection shape) measurement. Based on these results, the reliable finite element model was developed. Finally, various countermeasures were considered and applied to a real forklift truck and then its effects were confirmed.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.4
• /
• pp.381-389
• /
• 2010

Modern military equipments are often required to be mounted on a truck for their survivability and operation performance. Special units installed on the truck at times experience serious shock vibration caused by obstacles of road and/or uncommon road shape. It is then essential to analyze the travel performance of truck-mounted special units for their survivability and performance. In this paper, shock responses of the equipments subjected to bump passing and wash board road are experimentally obtained and also analyzed via FEM. Modified bump configuration and road profile considering the interface with tire are suggested. Analytical results considering this modification show good agreement with test results.

• Proceedings of the Safety Management and Science Conference
• /
• 2002.05a
• /
• pp.285-294
• /
• 2002

This study is focused on the operation of truck with conscious for environmental logistics system to reduce empty truck movements, and to control running empty truck. With the logistics function, road transport represents the biggest environmental threat. Using nonrenewable natural resources, contributing to air and noise pollution, trucks are environmentally unfriendly. Any steps to reduce transport activity will help minimize negative impact. In particular, noxious emissions must be reduced, but in the long term more environmentally friendly vehicles are required.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.25 no.6
• /
• pp.377-383
• /
• 2015

Torsion mode or bending mode of drive-line for rear-wheel drive vehicle exists in low frequency band. If resonance exists there between natural mode of driveline and powertrain excitation force, drive-line will manifest excessive vibration response. Also, the vibration response can be transmitted to vehicle body and can induce booming noise. A vehicle in this study exhibits a booming noise problem under specific transmission gear condition. To draw performance improvement plan, finite element analysis technique was used. Modification was evaluated qualitatively and priorities were derived. Finally, effectiveness of best modification was verified through test and full vehicle FE analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1996.04a
• /
• pp.155-160
• /
• 1996

The vibration analysis of the automobiles has been a good subject for the engineers seeking solutions for more comfortable life. In the area of industrial vehicles, however, the seriousness of the vibration annoyance has not been considered so much. In this paper, a finite element model was built which was good for the low-frequency system(of fork-lift truck), and a forced vibration analysis was obtained for the component of 2n of harmonic orders from engine excitation to this model. Finally, a design optimization upon dynamic responses was made to minimize the vibration acceleration level at selected points representing the vibration level of the whole system.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.24 no.2
• /
• pp.102-107
• /
• 2014

The engine excitation forces are considered as major vibration source for the forklift truck, especially in small class. Even though the current engine mounting system designs are acceptable for vibration isolation, the performance of the engine mounting system is still required for the tendency of light weight, higher power and driver's higher vibration requirement. In this paper vibration reduction technique of forklift engine which is supported on rubber mounts is presented. Based on the dynamic model of resilient engine mounting system, design evaluation program is established. The design optimization technique and evaluation method of system properties are discussed. Effects of optimal design are validated through comparison with test results.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.10
• /
• pp.1083-1091
• /
• 2009

Modern military equipments are tend to be mounted on a movable truck for their survivability and operation performance. Special units and electronic equipments installed on the truck experience the vibration caused by road roughness during their transport. The level of the transportation vibration is affected by both road conditions and vehicle speeds. In this paper, various experiments on the vibration characteristics of the equipment are carried out via road tests. Transportation vibration is also investigated by numerical analysis using FEM, and natural frequencies and random responses of the launcher are obtained. The PSD and RMS values of acceleration of the equipment are predicted and compared with test results.