• 소음진동
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• 제7권5호
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• pp.847-852
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• 1997

Many investigations about the dynamic analysis of the structural system based on the BBA(Building Block Approach) method which predict dynamic characteristics of synthesized structures from each structure. But it is actually sometimes difficult to remove mounts from structures. In this paper, TFSM(The Transfer Function Separation Method) is developed which can predict dynamic characteristics of separated structures from the data of vibrational experiment of the synthesized structures. By combining TFSM with BBA, this paper also proposes the method which can predict dynamic characteristics of mount-modified structure without removing mounts from structures. And the proposed method is verified by the experimental data of plates.

• 소음진동
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• 제5권1호
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• pp.29-35
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• 1995

This paper presents the simultaneous optimal design of structure and LQG control systems for the improvement of riding comforts of active vehicle suspension systems. The performance index of riding comforts is extended to include frequency-weighted acceleration in the quadratic cost functional. Janeway human response curve with respect to acceleration is used to verify the usefulness of the presented method. The method is applied to a half model of an active vehicle suspension systems with elastic body moving on randomly profiled road. The values of stiffness of suspensions are used for the structural design variables. The conjugate gradient method is used for optimization. The simulated results of simultaneous optimization with frequency-weighted cost functional are compared with those without frequency- weighted cost functional.

• 대한기계학회논문집
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• 제15권3호
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• pp.824-833
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• 1991

본 연구에서는 차체구조계의 진동모드 변수와 차실음향계의 음향모드변수들이 어떻게 관련되어 차실소음을 결정하는 가를 밝혔다. 그 결과, 수치해석 결과의 효용 성을 높이고 실내소음 평가방법을 체계화 시킬 수 있었으며, 효과적인 소음저감을 위 한 유용한 자료를 얻을 수가 있었다. 한편, 이제까지의 차실소음의 응답해석에서 가 장 큰 오차의 발생요인은 차체의 구조진동 모드데이타인데, 본 연구에서는 유한요소해 석 대신 모드시험 결과를 이용함으써, 유한요소 모델리이 어려운 경우의 소음 해석의 신뢰도를 높일수가 있었다.

• 대한조선학회논문집
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• 제45권2호
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• pp.186-191
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• 2008

A lot of equipments installed in ships must be isolated for relaxing the shock, vibration and noise using the elastic mounts. Most of the elastic mounts are made of the rubber, however it is not easy to design the effective rubber mount. Because, in general, the rubber has a non-linear constitutive characteristics especially for a large deformation. So, there are many difficulties to estimate the accurate structural response of rubber which is the basis of the shape design of the mounts. In this study, the detailed non-linear viscoelastic large deformation finite element analysis method was dealt with. And to verify validity of the present analysis scheme, the results were compared with experiments.

• 소음진동
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• 제9권2호
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• pp.348-354
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• 1999

An AC traction motor was developed, of which the rotor core has an unique structure, made of multi-layered silicon steel plates which were shrink-fitted to a shart. the equivalenet material properties were estimated with a newly proposed efficient method, based on the correlation between finite element analysis results and modal testing. A general rotordynamic analysis for the rotor with the equivalent material properties was carried out to evaluate the structural integrity of the virtually built-up motor.

• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.6-17
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• 2009

The present paper addresses development of a GTT NO96 membrane type 170K m3 LNG carrier targeted to operate in moderate ice infested seas including Baltic Sea, Sakhalin port of Sea of Okhotsk, Murmansk port of Barents Sea, etc. Critical design issues are covered in detail to meet the requirements coming from the missioned operation conditions comprising low design ambient temperature, harsh wave conditions, stringent environmental protection policies, etc.

• 소음진동
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• 제10권4호
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• pp.648-654
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• 2000

A procedure to determine the realizable optimal positions of rigid supports is suggested to get a maximum fundamental natural frequency. a measured frequency response function based substructure-coupling technique is used to model the supported structure. The optimization procedure carries out the eigenvalue sensitivity analysis with respect to the stiffness of supports. As a result of such stiffness optimization, the optimal rigid-support positions are shown to be determined by choosing the position of the largest stiffness. The optimally determined support conditions are verified to satisfy the eigenvalue limit theorem. To demonstrate the effectiveness of the proposed method, the optimal support positions of a plate model are investigated. Experimental results indicate that the proposed method can effectively find out the optimal support conditions of the structure just based on the measured frequency response functions without any use of numerical model of the structure.

• 한국구조물진단유지관리공학회 논문집
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• 제24권5호
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• pp.119-125
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• 2020

에폭시 계열의 합성수지와 골재를 혼합함으로써 진동저감 성능을 크게 증가시킨 고감쇠 콘크리트에 대한 연구가 활발히 진행되고 있는데, 이러한 폴리머 혼입 고감쇠 콘크리트는 배합 시, 시멘트와 물을 사용하지 않으므로, 일반 콘크리트에 비해 경화시간이 매우 짧고, 물리적 특성 및 동특성 등이 매우 우수하여, 층간소음 및 진동 저감이 요구되는 건축구조물에의 폭넓은 활용이 기대되고 있다. 한편, 폴리머 혼입 고감쇠 콘크리트의 활용성을 넓히기 위한 방안으로, 보강재 분야에 대한 연구가 다양하게 진행되어 왔으나, 폴리머 콘크리트가 일반 콘크리트 및 기존 방진보강재를 완전히 대체하기 위해서는 물리적 특성, 동적 물성, 생산성 및 현장 적용성 등을 고려하여 진동저감 성능에 대한 전반적인 검토가 필요한 실정이다. 본 연구에서는 폴리머 콘크리트의 에폭시 혼입비율별 물리적, 동적 특성을 일반 콘크리트와 비교한 결과, 탄성계수는 비슷한 반면, 압축, 인장, 휨강도가 상당히 우수한 결과를 보였으며, 특히 인장강도는 4~10배 이상 큰 차이를 보였으며, 주파수 응답함수와 감쇠비를 Modal 시험과 유한요소해석 모델을 통해 도출하여 검토한 결과, 폴리머 콘크리트의 동적 강성이 일반 콘크리트 보다 20% 크게 나타났고, 감쇠비는 약 3배 정도 높은 것으로 나타났다.

• 소음진동
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• 제9권6호
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• pp.1173-1179
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• 1999

A study was made on crack developments of the nearly building due to rock blasting for road construction at the 623 Common Block near the rear side of the Gamchun Habor. The gelogy of the study area is composed of andesite, which belongs to the Kyungsang System of the Cretaceous Period. For 3 months of blasting events, the vibration velocity data were measured at the site just in front of the K freezing factory. The data were divided into 4 groups according to the period of blasting(i.e, DATA 1, DATA 2, DATA 3 and DATA 4), for deriving K and n values. As a result, DATA 1 shows that K and n were 83.3756 and -0.848, respectively, and then K and n were progressively increased in absolute values for the follow-up groups and the last DATA 4 shows K and n were 2980.4898 and -1.502, respectively. Such differences in K and n values may be due to partly : 1) variations geological characteristics, from the upper rather weathered, fisssuring soft rocks at the earlier stage less weathered and fissuring hard rocks at the later stage of blasting events, and 2) the geometry between the blasting and detecting points.Among the total count of 225 blasting events, the number exceeding the safety limits of 0.5cm/sec was 20(8.9% of the total), the maximum displacement detected at the crack gage was 0.25mm, the level of which is far less to cause the occurrence and development of any cracks to the K factory. Therefore, it was confirmed that there were no damages such as structural failure or safety problem to the building.

• Design & Manufacturing
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• 제9권3호
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• pp.19-23
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• 2015

Non-pneumatic wheels have been widely used instead of general tube type wheels beause of many reasons, for example, wheel size, price restriction, heavy-duty problem and so on. Almost small size wheels or casters were non-pneumatic type but structural stability was not certified. This paper presents a double structured non-pneumatic wheel, called "smart caster", which consisted with inner and outer wheels connected by chips, and finite element analysis processes were conducted in order to determine important dwsign factors before actual design for mass production. For structural analysis ABAQUS was used under various boundary conditions with incrementally varied loads until 2,000N. Then structural staility was evaluated according to varied loads below ultimate stress. Generally stresses were concentrated at the lower parts of the wheel, and especially contact parts between wheel and ground. In addition, maximum stress appeared at contact parts between the wheel lower part and chips.