• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.387.1-387
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• 2002

In this paper, consideration of correlation between normal and random incidence is made by experiment and theory.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.620-621
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• 2012

• Journal of KSNVE
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• v.10 no.6
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• pp.971-976
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• 2000

High level random vibration environments induced while launching of spacecraft can damage sensitive electronic equipment, unless the equipment is properly packaged. Thus careful consideration on the launch environment, especially for high level random vibration, is required in the design stage of electronic equipment of spacecraft. This paper describes the development process of Solar Array Regulator for KOMPAT-2, which is designed and tested by Korean engineers. Both analytical and experimental techniques are introduced in this paper.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.59-67
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• 2014

Acceptance level random vibration and life firing test for development model of 1 N-class monopropellant thruster have been performed. From the results of random vibration, the natural frequency of the dual thurst module composed of 1 N-class development model thrusters was higher than the part level requirement(>100 Hz) and the structural robustness was verified. Thrust decrease of steady sate was below 7% and thrust instability was within ${\pm}5%$ in the life firing test using over 20 kg propellant throughput. The computerized tomography for catalyst bed showed a less than 7% of catalyst loss and it revealed the design appropriateness of the current thruster development model.

• Journal of KSNVE
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• v.8 no.6
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• pp.1023-1029
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• 1998

When one attempts to construct a hologram. one finds that there are many sources of measurement errors. These errors are even amplified if one predicts the pressures close to the sources. The pressure estimation errors depend on the following parameters: the measurement spacing on the hologram plane. the prediction spacing on the prediction plane. and the distance between the hologram and the prediction plane. This raper analyzes quantitatively the errors when these are distributed irregularly on the hologram plane The sensor mismatch and inaccurate measurement location. position mismatch. are mainly addressed. In these cases. one can assume that the measurement is a sample of many measurement events. The bias and random error are derived theoretically. Then the relationship between the random error amplification ratio and the parameters mentioned above is examined quantitatively in terms of energy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.130-135
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• 2011

A study of the bending-extension-transverse shear coupled random response of the composite beams with thin-walled open sections subjected to various types of concentrated and distributed random excitations is dealt with in this paper. First of all, equations of motion of thin-walled composite H-type cross-section beams incorporating a number of nonclassical effects of transverse shear and primary and secondary warping, and anisotropy of constituent materials are derived. On the basis of derived equations of motion, analytical expressions for the displacement response of the composite beams are derived by using normal mode method combined with frequency response function method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2491-2497
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• 1993

Random vibration of the coupled identical beams subject to band-limted white noise is studied. The mean-square displacements average dspatially over each beam are derived analytically using two different modal analysis techniques and compared to the results by SEA(Statistical Energy Analysis). It is shown that when frequency is high and a large number of modes are included in the frequency band, the modal analysis methods and the SEA yield the same results provided that the loss factors are very small and the modal separation is much larger than the half-power bandwidth.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.284-291
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• 1995

This paper proposes a method for determination of optimal reference spectrum in random vibration control. The least square method is used to minimize the spectrum deviation between the specified reference spectrum and spectra at the specimen-mounted points. This method needs only the measured FRF's at the control point and specimen-mounted points in pre-vibration test. Using the proposed method as reference spectrum, it is possible to easily predict spectra at the specimen-mounted points, and also to reduce overtest resulting from dynamic characteristics of shaker and fixture. This method is shown through theoretical and experimental results to be an effective method.

• Computational Structural Engineering
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• v.3 no.1
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• pp.51-57
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• 1990

The current load combination criteria for design of nuclear power plant structures(NPP) are not based on the probability-based design concept but rely on the conventional design concept. In this paper, a load combination criteria for design of NPP containment structures are proposed based on a FEM-based random vibration analysis. More accurate reliability analyses under various dynamic loads such as earthquake loads were made possible by incorporating the FEM and random vibration theory, which is different from the conventional reliability analysis method, In this paper, the toad factors for the design of NPP structures in Korea are proposed by considering appropriate load combination criteria for design.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.158-163
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• 1994

본 논문에서는 진동테이블의 가속도스펙트럼에 대한 치구 위의 제어점 및 시험물부착점들에서의 가속도스펙트럼을 실제 진동시험조건에서 낮은 진동레벨로 측정한 후, 측정된 전달함수를 이용하여 기준스펙트럼과 시험물 부착점들에서의 스펙트럼의 창를 최소화하기 위한 진동테이블(armature table)에서의 가속도스펙트럼 및 제어점에서의 기준스펙트럼을 최소자승법(Least Square Method)의 원리를 적용하여 구하는 방법을 제안하였다. 본 방법은 시험규격에서 정해진 기준스펙트럼으로 제어할 경우와 제안된 기준스펙트럼으로 제어할 경우, 시험물부착점들로 전달되는 스펙트럼을 컴퓨터 시뮬레이션을 통해 간단히 예측할 수 있으므로 제안 전.후 결과를 쉽게 비교, 확인할 수 있고 실험을 통해 이를 증명하므로서 본 논문에서 제안된 방법의 유용성을 확인할 수 있었다. 이와 같이 제안된 기준스펙트럼을 랜덤진동제어의 기준스펙트럼으로 사용하므로서 시험규격에 정해진 기준스펙트럼을 가능한 정확히 시험물에 전달할 수 있고, 시험물부착점들에서의 과대시험 또는 과소시험을 최대한 줄이므로서 보다 정확한 진동시험을 수행할 수가 있다.