• 대한기계학회논문집 C: 기술과 교육
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• 제5권2호
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• pp.81-87
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• 2017

315Fr 컴프레서용 모터가 진동 기준을 초과하는 문제가 발생하였고 이를 해결하기 위한 FEM해석과 모드실험을 수행하였다. 먼저 자유단 조건하의 해석과 실험을 수행하여 해석을 위한 조건을 확인하였다. 해석을 위한 Mesh, 재질, 경계 조건을 검토하였다. 여기서 얻은 결과를 바탕으로 볼트가 고정된 상태의 FEM 해석과 모드 실험을 수행하여 진동의 원인을 확인하였다. 모드실험 결과 121.7Hz에 Rolling 모드가 있음을 확인하였고 해석을 통해서도 동일한 결과를 얻을 수 있었다. 이 결과를 바탕으로 진동 기준을 초과하는 원인은 120Hz에 존재하는 Rolling 운동과 2X, 2fl 가진 주파수의 공진에 의한 것임을 알게 되었다. 여기서 얻은 결과를 바탕으로 추후 시리즈 설계에 있어서는 시험 모델 제작이나 실험 없이 해석만으로 문제점을 예측하고 해결할 수 있는 기술을 보유하게 되었다.

• 소음진동
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• 제5권2호
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• pp.215-224
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• 1995

In this paper, the three-dimensional finite element model is established to investigate the structural dynamic characteristics of rotor blade using a finite element analysis. Six natural frequencies and mode shapes are calculated by computer simulation. The first three flapping modal frequencies, the first two lead-lag modal frequencies, and the first feathering modal frequency are validated through comparison with the modal test results of the fixed rotor blade. The computer simulation results are found in good agreement with experimentally measured natural frequencies. The important results are obtained as follows: (1) Natural frequencies are changed due to the variation of rotational speed and fiber angle of rotor blade, (2) Weak coupling between flapping mode shape and lead-lag mode shape are detected, (3) Centrifugal force has more effect on flapping modal frequency than lead-lag modal frequency.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.229-238
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• 2009

In this paper, AWS ECU test method, which is considering behavior of a Bi-modal tram, is described. In order to evaluate the performance of an electronic automotive ECU, the method which combines HILS (Hardware In the Loop Simulation) and RBT (Requirement Based Testing) is introduced. HILS is the method to predict the behavior of a vehicle adopting an ECU. The behavior of a Bi-modal tram can be analyzed by using the vehicle dynamic model. Requirement Based Testing compare the outputs of a real system with a virtual electronic unit (oracle) which created by the requirements. Rear axles of the Bi-modal tram are independently controlled by two AWS ECU. Especially, swing out can happen when an articulated vehicle is operated in the curved road. Therefore dynamic behaviour of a Bi-modal tram is considered at this situation. Through this study, the reliability of ECU can be verified economically and safely using the proposed test method before conducting the track test.

• 한국소음진동공학회논문집
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• 제14권9호
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• pp.801-810
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• 2004

Parameter modification of a linear finite element model(FEM) based on modal sensitivity matrix is usually performed through an effort to match FEM modal data to experimental ones. However, there are cases where this method can't be applied successfully; lack of reliable modal data and ill-conditioning of the modal sensitivity matrix constitute such cases. In this research, a novel concept of introducing feedback loops to the conventional modal test setup is proposed. This method uses closed-loop natural frequency data for parameter modification to overcome the problems associated with the conventional method based on modal sensitivity matrix. We proposed the whole procedure of parameter modification using the closed-loop natural frequency data including the modal sensitivity modification and controller design method. Proposed controller design method is efficient in changing modes. Numerical simulation of parameter estimation based on time-domain input/output data is provided to demonstrate the estimation performance of the proposed method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.154-159
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• 1998

In this paper, BLDC spindle motor is designed using CAE/CAT to reduce structural vibration. Motor is modeled and analyzed using a finite element analysis (FEA) program and correlated to the results of modal test. Design sensitivity analysis (DSA) of frequency is carried out and validated by the modal test of modified motor manufactured. This study shows that simulation-based design can improve quality with reduced development time.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.283-290
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• 2007

A bi-modal tram has been developed to offer an advanced transportation service compared with existing vehicles. The All-Wheel-Steering system is applied to the bi-modal tram to satisfy the required steering performance because the bi-modal tram has extended length and articulated mechanism. An ECU for the steering system is essential to steer wheels on 2nd and 3rd axles by the specific AWS algorithm with the prescribed driving condition. The Hardware-In-the-Loop Simulation(HILS) system is planned for the purpose of evaluating the steering system of the bi-modal tram. There are kinematic links with the hydraulic actuator to steer wheels on each 2nd and 3rd axles and also same steering mechanism as the actual vehicle is in the HILS system. Controlling the movement of hydraulic actuator which reflects the lateral steering reaction force on each wheel is the key to realize the HILS system, but the reaction force is continuously changed according to various driving conditions. Therefore, the simulation through the multi-body dynamics model is used to obtain the required forces.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.840-845
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• 2004

Development of the linear motors is recently required to control a high-speed and high-resolution in the high-integrated and speed process industry. This paper presents vibration analyses as well as measurement standards of the newly developed linear motors through analyzing the vibration characteristics of the advanced products. Vibration experiments are conducted for identifying vibration level during operation. They are also included in the modal test to analyze dynamic characteristics. Analytic data using Finite Element Method (FEM) are compared with the results of the modal. The FEM and experiments make it possible to understand these characteristics. Further, through computer simulation for the behavior of moving part to be vibration source, the best acceleration pattern of moving part movement can be verified to achieve effective moving part positioning and reduce the vibration due to moving part movement.

• 정보저장시스템학회논문집
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• 제9권2호
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• pp.51-55
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• 2013

HDD has been easily exposed to the external shock and vibration because HDD has to apply to mobile devices. Therefore, the stiffness of base has been the important factors for the design of HDD. To improve the stiffness of base, the frame was applied to the base. First, the finite element model of the base was constructed. Then, the FE model was verified by modal analysis. Drop test was performed to confirming the shock simulation model. The dynamic characteristic of original base which is verified is compared with the base which is applied the frame through modal analysis and shock analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.864-869
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• 2004

A novel concept of feedback loop design for modal test and model updating is proposed. This method uses the closed -loop natural frequency information for parameter modification to overcome the problems associated with the conventional method employing the modal sensitivity matrix. To obtain new modal information from closed-loop system, controllers should be effective in changing modal data while guaranteeing the stability of closed-loop system. It is very hard to guarantee the stability of the closed-loop system with non-collocated sensor and actuator set. Ill this research, we proposed a controller called mode-decoupling controller that can change a target mode as much as the designer wants guaranteeing the stability of closed-loop system. This controller can be computed just using measured open-loop modeshape matrix. A simulation based on time domain input/output data is performed to check the feasibility of proposed control method.

• 한국소음진동공학회논문집
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• 제14권10호
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• pp.955-961
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• 2004

A novel concept of feedback loop design for modal test and model updating is proposed. This method uses the closed-loop natural frequency information for parameter modification to overcome the problems associated with the conventional method employing the modal sensitivity matrix. To obtain new modal information from closed-loop system, controllers should be effective in changing modal data while guaranteeing the stability of closed-loop system. But it is very hard to guarantee the stability of the closed-loop system with non-collocated sensor and actuator set. In this research, we proposed a controller called mode-decoupling controller that can change a target mode as much as the designer wants guaranteeing the stability of closed-loop system. This controller can be computed Just using measured open-loop modeshape matrix. A simulation based on time domain input/output data is performed to check the feasibility of proposed control method.