• 한국산학기술학회논문지
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• 제13권4호
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• pp.1434-1439
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• 2012

차량은 여러 가지 설계변수가 결합된 동적계이다. 차량의 운동특성은 이러한 설계변수의 변화에 따라 변하게 된다. 설계변수의 조종안정성에 대한 영향을 파악하기 위하여 현가장치나 조향장치 특성이 포함된 등가코너링강성을 고려한 차량의 조종안정성 모델에 대하여 수치해법에 의한 민감도 해석을 수행하였다. 민감도 해석결과로부터 차량설계변수인 무게중심위치, 타이어 코너링특성, 현가장치 및 조향장치의 특성의 변화에 대한 정상상태이득, 스테빌리티 팩타, 주파수응답 등 차량 조종안정성의 변화율을 파악할 수 있었다. 또한 민감도 해석은 정성적이고 정량적인 결과를 제공하므로 설계단계는 물론 차량개발단계에서도 차량의 성능향상을 위한 설계변수들의 최적화에 사용될 수 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 춘계학술대회논문집; 부산수산대학교, 10 May 1996
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• pp.316-321
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• 1996

The authors has developed the transfer influence coefficient method(TICM) which is an algorithm for the analysis of vibration suitable for a personal computer and applied to many structures such as straight-line beam, plate and shell structures. But TICM can't be applied to the closed loop system and is required extremely much time on the computation of complicate and large structures. Therefore, we now suggest the transfer stiffness coefficient method(TSCM) overcoming these two problems, which consists on the concept of the substructure synthesis method and transfer influence coefficient method. TSCM is formulated for the free vibration analyses of a straight-line distributed beam structure and confirmed by the results of numerical computation to the numerical high accuracy and the high speed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1871-1874
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• 2000

It is impossible to predict accurately the dynamic behavior of turbine-generator system because bearing, and rotor characteristics are nonlinear and different from temperature, load, operation speed and bearing lubricant oil property. Especially, the characteristics of turbine hoods affect much the entire vibration characteristics of turbine. As the dynamic stiffness of turbine hoods are changed, the critical speeds of rotor are shifted. In this paper, the vibration behavior of turbine-generator is analyzed by using component mode synthesis and the critical speeds measured during shut-down are compared with the analytic results. It is confirmed that the 1st natural frequency and the mode shape are well in agreement with actual measured data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.169-175
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• 1997

Recently it is increased by degrees to produce complex and large lattice structures such as bridge, tower, crane, and space structures. In general, in order to analyse these structures we have used finite element method(FEM). In this method, however, it is necessary to use a large amount of computer memory and to take long computation time. For overcoming this problem, the Authors have developed the transfer dynamic stiffness coefficient method(TDSCM) which consists on the concept of the substructure synthesis method and transfer influence coefficient method. In this paper, the new free vibration analysis method for large type lattice structure is formulated by the TDSCM. And the results obtained by TDSCM are compared with those obtained by FEM, transfer matrix method and experiment. And it is confirmed for TDSCM to be the numerical high accuracy and high speed structure analysis method.

• Journal of Mechanical Science and Technology
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• 제18권9호
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• pp.1529-1536
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• 2004

A structure is broken down into a number of substructures by means of the finite element method and the substructures are synthesized for the complete structure. The divided substructures take two types: fixed-free and free-free elements. The flexibility and stiffness matrices of the free-free elements are the Moore-Penrose inverse of each other. Thus, it is not easy to determine the equilibrium equations of the complete structure composed of two mixed types of substructures. This study provides the general form of equilibrium equation of the entire structure through the process of assembling the equilibrium equations of substructures with end conditions of mixed types. Applications demonstrate that the proposed method is effective in the structural analysis of geometrically complicated structures.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1003-1008
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• 2007

Compliance effect consideration method for real-time multibody vehicle dynamics is proposed using quasi-static analysis. The multibody vehicle model without bush elements is used based on the subsystem synthesis method which provides real-time computation on the multibody vehicle model. Reaction forces are computed in the suspension subsystem. According to deformation from the quasi-static analysis using reaction forces and bush stiffness, suspension hardpoint locations and suspension linkage orientation are changed. To validate the proposed method, quarter car simulations of McPherson strut and multilink suspension subsystems. Full car bump run simulations are also carried out comparing with the ADAMS vehicle model with bush elements. CPU times are also measured to see the real-time capabilities of the proposed method.

• 대한기계학회논문집A
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• 제32권2호
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• pp.162-169
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• 2008

Compliance effect consideration method for real-time multibody vehicle dynamics is proposed using quasi-static analysis. The multibody vehicle model without bush elements is used based on the subsystem synthesis method which provides real-time computation on the multibody vehicle model. Reaction forces are computed in the suspension subsystem. According to deformation from the quasi-static analysis using reaction forces and bush stiffness, suspension hardpoint locations and suspension linkage orientation are changed. To validate the proposed method, quarter car simulations of McPherson strut and multilink suspension subsystems are performed. Full car bump run simulations and fish hook handling test simulations are also carried out comparing with the ADAMS vehicle model with bush elements. CPU times are also measured to see the real-time capabilities of the proposed method.

• 소음진동
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• 제10권4호
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• pp.575-583
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• 2000

In this paper, we design a vibration control system that includes a 3-D.O.F. mass-spring-damper structure for the analytical model of a building that is excited at the base of this structure by an external dynamic force, and one Active Mass Damper(AMD) on the top of this structure to generate control forces fro attenuation of the structural response. Two robust controllers based on $\mu$-synthesis and H$\infty$ optimal control are designed for the structural system to show that the performance of a control system can be degraded by some parameter uncertainties such as mass, stiffness coefficients, and/or damping coefficients. The performance of the two controllers are compared in terms of nominal performance, robust stability and robust performance by simulations.

• 전자공학회논문지T
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• 제36T권3호
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• pp.41-49
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• 1999

본 논문에서는 μ-합성법으로 제어기를 설계하여 센서와 구동부가 동일위치에 있지 않은(noncollocated) 탄성-질량 시스템에 적용한다. 스프링 상수값과 제어대상의 부하 질량은 불확실하다고 가정한다 매개변수 불확실성을 포함하고 있는 제어대상은 상태 공간 방정식, 특히 묘사형(descriptor form)을 사용하여 모델링 한다. μ-합성법으로 설계된 H/sub ∞/ 제어기를 표준 H/sub ∞/ 제어기와 비교한다. 두 개의 H/sub ∞/ 제어기 성능을 비교하기 위해, μ-합성 제어기가 구조적 불확실성을 가지고 있다는 것을 제외하고는 서로 동일한 하중함수를 가지고 설계한다. 표준 H/sub ∞/ 제어기와 비교하여 설계된 제어기는 만족스러운 강건 안정성과 강건 성능을 가지는 것을 시뮬레이션과 실험을 통해 확인한다.

• 소음진동
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• 제6권1호
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• pp.71-82
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• 1996

The finite element analysis for rotor bearing systems has been an essential tool for design, identification, and diagnosis of rotating machinery. Among others, the unbalance response analysis is fundamental in the vibration analysis of rotor bearing systems because rotating unbalance is recognized as a common sourve of vibration in rotating machinery. However there still remains a problem in the aspect of computational efficiency for unbalance response analysis of large rotor bearing systems. Gyroscopic terms and local bearing parameters in rotor bearing systems often make matters worse in unbalance response computation due to the complicated dynamic properties such as rotational speed dependency and/or anisotropy. The present paper proposes an efficient method for unbalance responses of multi-span rotor bearing systems. An improved substructure synthesis scheme is introduced which makes it possible to compute unbalance responses of the system by coupling unbalance responses of substructures that are of self adjoint problem with small order matrices. The present paper also suggests a scheme to easily deal with gyroscopic tems and local, coupling or bearing parameters. The proposed method causes no errors even though the computational effort is reduced drastically. The present method is demonstrated through three test examples.