• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.207-212
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• 2006

A dynamic analysis of a tilting actuator for projection TV is presented in this study. Generally, an excessive vibration of a tilting actuator is occurred a lowering of video quality of projection TV because of a dynamic unstability of it. Therefore, a dynamic analysis of a tilting actuator system is positively necessary. In this study, a mathematical model about a mirror-reactive type tilting actuator is presented and evidenced by experiment. A FEM model of a lens-transmissive type tilting actuator is presented and we made prototype of it. Then, it is evidenced by experiment. Besides, a design for hinge configuration of it is presented.

• 전기학회논문지
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• 제59권2호
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• pp.318-327
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• 2010

This paper deals with analysis on dynamic characteristic and circuit parameter of linear switched reluctance motor by electromagnetic analytical method. Above all, using space harmonic method, which is electromagnetic method, the air-gap flux density is analyzed in the both align and unaign positions, and the inductance profile, force characteristic and resistance per phase are calculated by means of the process. The validity of the analyzed results are demonstrated by the finite element method(FEM) and manufacture of the prototype machine. Second, the dynamic simulation is analyzed by the use of circuit parameters derived from analytical method, and the operating system of the prototype machine is manufactured to demonstrated the validity of simulation analysis. As a result, it is considered that the characteristic equation suggested in this paper will contribute to the design, analysis and application of LSRM.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.1-6
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• 1998

A leaf spring plays an important role in a passenger bus. Since characteristic of a leaf spring has a hysteresis behaviour, modeling technique for a leaf spring is an important issue for passenger bus analysis. In this paper, modeling technique for a leaf spring is presented. First, non-linear FEM model of a leaf spring is constructed then it is used to make an approximated model to be used in dynamic analysis. The modeling procedure is ex-plained in step by step approach. Then, this model is applied to dynamic analysis of a mini-bus with flexible body and non-linear dynamic force element. The results are compared with test data.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.353-362
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• 2000

Herringbone groove journal bearing (HGJB) is developed to improve the static and dynamic performances of hydrodynamic journal bearing. In this study, static and dynamic compressible isothermal lubrication problems are analyzed by the finite element method together with the Newton-Raphson iterative procedure. This analysis is introduced for prediction of the static and dynamic characteristics of air lubricated HGJB for various bearing configurations. The bearing load characteristics and dynamic characteristics are dependent on geometric parameters such as asymmetric ratio, groove depth ratio, groove width ratio and groove angle.

• 한국정밀공학회지
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• 제16권9호
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• pp.149-158
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• 1999

The modern trends of optical storage devices can be characterized by high density in information recording, and high bandwidth in data input/output processing rate. These make servo engineers to face with a new barrier on control system design in much more difficult way. The first step to attack this barrier will be through a systematic modeling for the dynamic characteristics of optical storage drive. in this paper, an analytical dynamic model for an optical storage drive based on FEM is drived, and compared with experimental results. Through this comparison, a practical dynamic model on the focusing and tracking motion of optical storage drive is proposed for the initiation of real control system design problem.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.848-851
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• 2005

ATM(Automated-feller Machine) is a machine that receives and pays money directly. The double bill detector (DBD) module of an ATM detects double bill from its thickness. In this paper, the dynamic behavior of the DBD was analyzed numerically and experimentally. The moment of inertia of the double bill lever and the spring constant were measured respectively. And the displacements of the ]ever was measured experimentally. The measured dynamic behaviors were simulated numerically using vector equation. Through the analysis, the design factors were found to make a fast and reliable new ATM machine.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.106-113
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• 2004

Most of mechanical structures are composed of many substructures connected to one another by various types of mechanical joints. In automotive engineering, it is important to study these connected structures under various dynamic forces for the evaluations of fatigue life and stress concentration exactly. In this study, the dynamic response of vehicle structure to external forces is classified an inverse problem involving strains from the experiment and the analysis. The practical dynamic forces are determined by the combination of the analytical and experimental method with analyzed strain by quasi-static finite element analysis under unit force and with measured strain by a strain gage under driving load, respectively. In a stressed body, inter-molecular chemical bonds are failed beyond the certain magnitude. The failure of molecular structure in material is considered as a time process of which rate is determined by mechanical stress. That is, the failure of inter-molecular chemical bonds is the fatigue lift of material. This kinetic concept is expressed as lethargy coefficient. And S-N curve is obtained with the lethargy coefficient from quasi-static tensile test. Equivalent practical dynamic force is obtained from the identification of practical dynamic force for one loading point. Using the practical dynamic force and S-N curve, fatigue life of a window pillar is analyzed with FEM under the identified force by the procedure of above mentioned.

• Advances in aircraft and spacecraft science
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• 제5권3호
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• pp.385-400
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• 2018

In this paper dynamic behavior (modal analysis and dynamic transient response) of a novel sandwich T-joint is numerically and experimentally investigated. An epoxy adhesive is selected for bonding purpose and making the step wise graded behavior of adhesive region. The effect of the step graded behavior of the adhesive zone on dynamic behavior of a sandwich T-joint is numerically studied. Finite element analysis (FEA) of the T-joints with carbon fiber reinforced polymer (CFRP) face-sheets is performed by ABAQUS 6.12-1 FEM code software. Modal analysis and dynamic half-sine transient response of the sandwich T-joint are presented in this paper. Two verification processes employed to verify the dynamic modeling of the manufactured sandwich panels and T-joint modeling. It has been shown that the step wise graded adhesive zone cases have changed the second natural frequency by about 5%. Also, it has been shown that the different arranges in the step wise graded adhesive zone significantly affect the maximum stresses due to transient dynamic loading by 1112% decrease in maximum peel stress and 691.9% decrease in maximum shear stress on the adhesive region.

• 한국정밀공학회지
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• 제21권8호
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• pp.120-128
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• 2004

The impulse between launch vehicle and atmosphere can generate a lot of noise and vibration during the process of launching a satellite. Structurally, the electronic equipment of a satellite consists of an aluminum case containing PCB. Each PCB has resistors and IC. Noise and vibration of the wide frequency band are transferred to the inside of fairing, subsequently creating vibration of the electronic equipment of the satellite. In this situation, random vibration can cause malfunctioning of the electronic equipment of the device. Furthermore, when the frequency of random vibration meets with natural frequency of PCB, fatigue fracture may occur in the part of solder joint. The launching environment, thus, needs to be carefully considered when designing the electronic equipment of a satellite. In general, the safety of the electronic equipment is supposed to be related to the natural frequency, shapes of mode and dynamic deflection of PCB in the electronic equipment. Structural vibration analysis of PCB and its electronic components can be performed using either FEM or vibration test. In this study, the natural frequency and dynamic deflection of PCB are measured by FEM, and the safety of the electronic components of PCB is evaluated according to the results. This study presents a unique method for finite element modeling and analysis of PCB and its electronic components. The results of FEA are verified by vibration test. The method proposed herein may be applicable to various designs ranging from the electronic equipments of a satellite to home electronics.

• 대한기계학회논문집A
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• 제20권2호
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• pp.461-472
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• 1996

The relationship between plastic deformation and crystal grain change in warm forging processes of SM10C carbon steel is studied. If the carbon steel is deformed at warm forging temperature(about recrystallization range), material properties are changed due to microstructural chanre of the crystal grain and cementite of the internal part. Some experimental values are investigated in terms of the elliptic degree of cementite, the grain size of cementite and ferrite grain size. When plastic deformation proceeds, the elliptic degree of cementite becomes larger and the grain size of cementite particle becomes small. In addition, the size of ferrite grain becomes fines by recrystallization. The elliptic degree of cementite has a considerable effect on formability. The distribution of effective strain in the forging was calculated by the rigid visco-plastic FEM analysis. The effective strain distribution obtained from the FEM simulation is compared with the experimental result, At the level of effective strain 0.3, dynamic recovery and dynamic recrystallization begin and at the level of over 2.5, the organization of material has better internal structure that is suitable for the following cold forming.