• Journal of Applied Reliability
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• v.18 no.3
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• pp.213-219
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• 2018

Purpose: Satisfying the environmental regulations, the automobile manufacturer should install urea tank, which is a key component of the urea system. However, due to the limitations of existing layouts, it may be mounted which is disadvantageous to vibration and shock resulting in durability robust. analyze the factors affecting the durability life of urea tank and the vibration characteristics through RLDA. In this study, clarify the limit of the current practice test method of urea tank and analyze the possibility of the new vibration test method in the system unit reflecting the characteristics of actual use condition. Methods: Analyzing the factors affecting the durability life of urea tank and the vibration characteristics through PSD & FDS of RLDA that actual vehicle driving data on durability test road. Results: The limit of the uniform width/single frequency test method of urea tank is clarifed and the positive prospects of the new test method are discovered. Conclusion: The vibration durability test with PSD method in system unit effectively reflects the magnitude and frequency characteristics of field vibration.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.4
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• pp.365-373
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• 2011

This paper presents the dynamic response and the vibration characteristics for a rail-track supported by discrete springs and dampers. Recently, automatic conveyer system, rail-track, rack-master system demand the soundproof facilities and vibration suppression measures in order to satisfy the strict environmental standards. The equations of motions of the dynamic characteristics for a vibration suppression rail-track under a traveling mass were derived by Galerkin's mode summation method considering gravity, centrifugal force, Coriolis force, inertia force of the moving mass, transverse inertia of the rail-track. Also, numerical results were calculated by Runge-Kutta integration method. In order to investigate vibration characteristics and dynamic responses, modal testing and measurement of the responses of the rail-track were performed. Through the experiment and numerical simulations, numerical results have a good agreement with experimental ones.

• Journal of Biosystems Engineering
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• v.26 no.1
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• pp.11-20
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• 2001

Experiments under the stationary and harvesting condition, were performed in order to investigate the vibration characteristics of a head-feeding combine. 6 degrees of freedom components of acceleration at the location of the center of the gravity, and 3 degrees of freedom components of acceleration at the location of the operator seat were measured independently. The vibration characteristics of the combine were estimated with the power spectral density of the time series data of accelerations. From this research, the following results were obtained. 1. Vibration of a head-feeding combine under the stationary condition(engine, thresher and cutter are driven without harvesting) is mainly influenced by the engine. Further, 1/3, 1/2 (sub-harmonic) frequency components of the engine are observed besides engine driving frequency component(45Hz). 2. Vibration of a head-feeding combine under the harvesting condition is influenced by the engine, threshing unit and driving unit. Namely, some kinds of vibration frequency components in harvesting are observed compared with stationary condition. Further, sub-harmonic frequency components of the engine are observed besides engine driving frequency component as same as stationary condition. From these results, it may be concluded that vibration of a head-feeding combine is characteristics of semi-periodic and nonlinear vibration.

• Progress in Medical Physics
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• v.5 no.2
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• pp.77-85
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• 1994

In this paper, the vibration response characteristics of individual's subjective are studied to whole-body and hand-arm induced vibration. For defining limits of vibration exposure to human, experimental data are investigated in a set of vibration criteria specified in ISO Standard 2631. Instrumentation requirements for evaluation of the responses of humans to vibration according to these criteria are discribed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.348.1-348
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• 2002

This paper deals with the vibration reduction of the hull mount system of ship structures brought by ER smart structures. The hull mount is used to isolate the vibration form the immersed structures. Utilizing the tunable characteristics of ER fluids, ER insert are made In the hull mountint structure. Different types of ER inserts are proposed and the vibration characteristics are investigated. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1259-1265
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• 2007

This paper presents nonlinear vibration characteristics of a vertical passive zero stiffness isolator. The passive isolator can achieve zero stiffness through buckling of notched flexure caused by a compressive force. First, a simulation model of the isolator was built based on elastic beam theory. As increasing the compression force, time and frequency responses of the isolator were simulated. In addition, further nonlinear vibration characteristics were investigated through a bifurcation diagram and a Poincare's map, which shows that even chaostic vibration could happen. The simulations show that as the compressive force increases, the stiffness goes close to zero and the nonlinear characteristic becomes stronger to have a great effect on the isolation performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.49-53
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• 2008

This study deals a way to reduce the transformer noises. The first step is to identify the source of the transformer noises. The second step is obtaining the vibration characteristics of transformer; its natural frequencies and mode shapes. Based on these information, an method to reduce the vibration of transformer can be found. The cause of transformer noises is mainly due to the magnetostrictive vibration of a core which is made of ferromagnetic substances. It is well known that the magnetostrictive vibration of a core is unavoidable, and a way to reduce the transformer noise by structural design is needed. It requires understanding the vibration characteristics. The natural frequencies and the mode shapes of transformer are analyzed by performing the modal testing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.453-458
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• 2002

This paper deals with the vibration reduction of hull mount system of ship structures brought by ER smart structures. The hull mount is used to isolate the vibration of equipment from the host structures. Utilizing the tunable characteristics of ER fluids, ER inserts are made in the hull mount structure. Different types of ER inserts are proposed and the vibration characteristics are investigated. A hull mount structure is made and the influence of ER inserts are experimentally studied. An extensive modal test is empirically conducted to identify natural frequencies and mode shapes according to the applied electric field and the types of ER insert. The frequency tunable characteristics of ER inserts can be applied to many mounting structures for vibration reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.155-160
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• 2001

This study is performed to evaluate and design the vibration characteristics of the onboard machinery with resilient mountings. To reduce the vibration level of onboard machinery with resilient mountings, it is important to evaluate and, if necessary, modify the vibration characteristics of the resilient mountings. In this study, we have developed a program to calculate natural frequencies of the machinery with resilient mountings, forced vibration levels due to internal excitation force of the machinery itself and external excitation forces. of the main engine and the propeller. and the force and motion transmissibility of the resilient mountings. The developed program is also able to be applied to optimal design of the resilient mountings for obtaining a target natural frequency and for achieving a minimum forced vibration level at the center of gravity of the machinery.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.171-176
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• 2001

Recent building structures are superior in its ability but they are light and flexible, and so have problems of vibration. In general, the problem of vertical vibration is not considered in structural design. However, in terms of serviceability for inhabitants in buildings, the estimation of vibration in design stage is important. Characteristics of vertical vibration is changed by modeling method of beam-column joint. To check the characteristics of vertical vibration, many tests and analyses were conducted on constructing building in Seoul. Results of tests and analyses were compared using transfer function. As a results, to check the vertical vibration, the cramp ratio of beam-column joint must be considered and reduced in structural design.