• 한국항공우주학회지
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• 제33권5호
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• pp.41-49
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• 2005

본 논문에서는 KF-16D 항공기의 동특성을 실험적으로 규명하기 위해 수행한 지상진동시험의 시험 방법, 센서 및 장비 설치, 시험 결과 검증 방법 및 시험 결과를 기술하였다. 지상진동시험은 외부 장착물 장착 형상에 따라 7가지 형상으로 분류하여 실시하여 외부장착물 부착 형상에 따른 항공기의 동특성 변화를 정량적으로 산출하였고 비행 중 항공기 진동 모드의 정량적인 변화량을 예측할 수 있게 하였다. 항공기 지지는 항공기 비행 상태의 조건을 구현하기 위하여 착륙장치 타이어의 공기압을 최소로 하였다. 시험은 6개~8개의 가진기를 사용하여 다점 랜덤 가진법으로 항공기를 가진하고 약 200개의 가속도계로부터 항공기의 응답을 측정하였다. 시험결과 관심 있는 낮은 주파수영역에서 선형성을 보여 양질의 주파수 응답함수를 얻었으며, 상반성을 만족함을 알 수 있었다. 측정된 가진력과 응답신호로부터 주파수 응답 함수를 구하였으며, 고유 진동수와 감쇠 계수는 주파수 응답함수로부터 다기준 최소 자승 복소 지수법을 적용하여 산출하였다. 고유진동모드는 최소 자승 주파수 영역법으로 사용하여 구성하였다.

• 한국정밀공학회지
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• 제33권10호
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• pp.805-811
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• 2016

Prior to installation in a navy ship, shipboard equipment should be qualified by shock test requirements. The multi-function console mounted on the elastic platform of the ship should also withstand given shock loads. In this study, both real shock test methods, as well as numerical computer simulations using the finite element method were used to verify structural durability under shock load conditions. First, we used domestic test facilities to perform possible shock tests, including an impact hammer test, a drop table test and a shaker shock test. Full model tests satisfying the shock response spectrum level were performed. Thereafter, an analytical model of the complex console structure was built by the finite element method. Finally, numerical results were verified by modal test results of the real product and an FEA analysis was also performed with a full model transient response analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1051-1059
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• 2008

In the development process of an ECU (Electrical Control Unit), numerous tests are necessary to evaluate the performance and control algorithm. The vehicle based test is expensive and requires long time. Also, it is difficult to guarantee the safety of the test driver. To overcome the various problems faced in the development process, the ECU test has been done using HIL (Hardware In the Loop). The HIL environment has the actual hardware including an ECU and a virtual vehicle model. In this paper, the test platform environment is devloped for the AWS ECU black box test. The test platform is built on HIL (Hardware In the Loop) architecture. Using the developed test platform, the control algorithm of the AWS ECU can be evaluated under the virtual driving condition of the bi-modal tram. Driving conditions, such as a front steering angle and vehicle velocity, are defined through the PC (Personal Computer) input. Input signals are transformed to electrical signals in the PC. These signals become the input conditions of the AWS ECU. The AWS ECU is stimulated by arbitory input conditons, and responses of the system are observed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.905-910
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• 2004

Vibration characteristics of the FIV test loop for the Flow-Induced Vibration(FIV) study of a PWR partial(5x5) fuel assembly are investigated by the Finite Element(FE) analysis and the modal test. For the FE analysis, 3-D beam element is used for the pipes and the test section and mass element used for the valves and flanges. The 'U' restrainer stiffness determined by numerical simulation is used for the FE model. The result of the FE analysis is compared with that of the modal test. The higher mode similarity between the test and analysis is observed in a few low modes. After that, the mode similarity reduce as the mode goes high. It is concluded that the first to the third vibration modes are observed at the lower parts of the 6 inches restoring line, followed by a local mode at the test section, and the natural frequencies of the modes are 22.4 Hz, 26.0 Hz, 27.5 Hz and 31.4 Hz.

• 한국소음진동공학회논문집
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• 제20권8호
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• pp.727-733
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• 2010

Optical tables provide a platform for the establishment and test of measurement systems which use Laser. Therefore, not only static characteristics such as surface flatness, static stiffness and etc. but dynamic response characteristics is very important design parameter. The dynamic stiffness is generally estimated through the modal test, and compliance is used as a representative performance standard. Recently there is an example of defining the dynamic deflection coefficient and using it as a new performance standard of the dynamic stiffness, but it is not generalized yet in industry. In this study, we verify the validity of existing DDC calculus by making an experiment on granite. And for improvement in damping performance of optical tables, we are going to evaluate the effect of fillers on the compliance, then develop an epoxy adhesive based on the result of this experiment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.403-408
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• 2007

According as diesel automobile are produced, reduce noise and vibration that is occurred by characteristic of diesel engine, and need engine room layout optimization and research for light weight of parts. Balance Shaft Module is module parts for vehicles engine to improve performance and efficiency of engine and reduce noise and vibration. These days, an oil pump integrated balance shaft module and an oil sump integrated balance shaft module is on the rising for optimizing of engine room. In this study, produced prototype of oil pump integrated type balance shaft module, and achieved dynamic characteristic test about experimental modal analysis and noise/vibration of balance shaft module.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1590-1594
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• 2007

This paper describes a case study on dynamic characteristics analysis of a 5-axis multi-tasking machine tool of ram-head typed. Natural frequency and corresponding vibration modes of the machine tool structure were obtained by using both FEM modal analysis and an experimental modal test(impulse hammer test). Both the theoretical and experiment analysis results showed good agreement with each other. Finally, some discussion and review, from the view point of resonance vibration and/or mode coupled chatter, were made based on the analysis results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.826-831
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• 2002

In order to investigate the dynamic characteristics of real structure, many dynamic engineer had been interested in modal test however it is not easy to perform dynamic test of large structure because of many difficulties such as unsatisfied excitation force in global mode frequency range, measurement of dynamic force and so on. Therefore. new type vibration exciter with variable stiffness support system and dynamic force was developed to provide a improved experimental environment for a large and complex structure. The developed exciter improved from two viewpoint, dynamic performance and utility convenience. its characteristics was shown in this paper.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.113-116
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• 2005

In this study, in order to. investigate the effectiveness af tuned liquid damper (TLD) for the seismic performance enhancement af the existing reinforced concrete (RC) apartment structure which is nat seismically designed, shaking table test was conducted for the small scale five stary RC structure with TLD. TLD model was constructed to. have the frequency tuned to. the first modal frequency af the structure, $2\%$ mass ratio. af the first modal mass, and 0.08 liquid depth ratio. White noise with $0.2\~5Hz$ frequency bandwidth tests were performed using the shaking table at Korea Institute af Machinery and Materials, and the displacement and absolute acceleration af each floor were measured. Test results indicate that mare than $30\%$ seismic responses reduction can be achieved using TLD for RC structure under white noise.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.490-495
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• 2001

This paper deals with an analysis and countermeasure for improving the shock performance of laptop computers. The shock analysis is carried out by using the commercial program of LS-DYNA3D. Also the analysis is verified by the measurements from modal tests and shock tests. The available countermeasures are investigated theoretically and experimentally to find the effective methods of reducing the shock acceleration on hard disk driver during one side fall test. The hard disk drive is the most sensitive part in a laptop computer. This research shows the effects of the spring constant of rubber pad, the reinforcement of mechanical parts and the location of a hard disk driver, on the shock reduction.