• 제목/요약/키워드: noise types

검색결과 1,131건 처리시간 0.026초

강제 가진에 의한 교량 플러터계수 추출 (Extraction of bridge flutter derivatives by a forced excitation)

  • 이승호;권순덕
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2009년도 춘계학술대회 논문집
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    • pp.538-544
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    • 2009
  • A vibration excitation system was designed and built of forced vibration experiments for using stepping motor and load cell. The identified flutter derivatives of the thin-plate acrylic model were very close to the analytical results of the idealized plate presented by Theodorsen. Five types of sectional models were tested in the wind tunnel using the proposed forced vibration method. To investigate the frequency, amplitude and angle of attack effects on flutter derivatives.

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두 가지 발성 유형에 따른 한국어 파열음의 조음 위치 인지도(認知度) 차이 (Differences of Perceptual Correctness in the Place of Articulation Between Korean Plosives According to Two Phonation Types)

  • 서승완
    • 대한음성학회:학술대회논문집
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    • 대한음성학회 2007년도 한국음성과학회 공동학술대회 발표논문집
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    • pp.84-87
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    • 2007
  • The final purpose of this paper is to prove that, under noisy environment, there is significant difference of perceptibility of the place of articulation between fortis plosives and aspirated plosives in Korean. For this research, a perceptual experiment had been made. Two groups of subjects heard stimuli with noise and were required to answer which sound they had heard. The result is that, with noise, aspirated plosives cannot be heard clearly whereas fortis plosives can be heard well.

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ER인서트를 이용한 Hull Mount에서의 진동저감에 관한 연구 (Vibration reduction in a Hull mount using the ER inserts)

  • Kim, Ji-Seon;Kim, Jae-Hwan;Park, Seung-Bok;Kim, Kung-Su
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문초록집
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    • pp.348.1-348
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    • 2002
  • This paper deals with the vibration reduction of the hull mount system of ship structures brought by ER smart structures. The hull mount is used to isolate the vibration form the immersed structures. Utilizing the tunable characteristics of ER fluids, ER insert are made In the hull mountint structure. Different types of ER inserts are proposed and the vibration characteristics are investigated. (omitted)

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웨이브렛변환을 이용한 기어결함의 진단 (The Detection of Gear failures Using Wavelet Transform)

  • Park Sung-Tae;Gim Jae-Woong
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문초록집
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    • pp.363.1-363
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    • 2002
  • This paper presents that the Wavelet Transform can be used to detect the various local defects in a gearbox. Two types of defects which are broken tooth and localized wear, are experimented and the signals are collected by accerometer and acoustic sensors and analyized. Because of the complecity of the signals acquired form sensors, it is needed to identify the interesting signal. (omitted)

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벽식구조 아파트의 고유진동수 측정에 관한 연구 (Measurement of First Natural Frequency in Apartments with Shear Wall)

  • 김하근;김흥식;천영수;김명준
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2001년도 춘계학술대회논문집
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    • pp.1065-1069
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    • 2001
  • This study aims to suggest the basic data for structural safety assessment and design considering building dynamic characteristics. For this purpose, ambient vibration measurement was practiced after studying international standards dealing with vibration measurements such as ISO, DIN and so on. Various types of situation and condition which help search the building natural frequencies through the field measurements were proposed.

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정규모드의 안정성 변화에 따른 분기모우드의 계산법 (Computations of bifurcating modes due to the stability change of normal modes)

  • 박철희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.435-440
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    • 2000
  • It is shown, in nonlinear two-degree-of freedom system, that the bifurcating modes are created by the stability changes of normal modes. There are four types of stability criterion, each of which gives rise to a distinct functional form of bifurcating modes; the bifurcating mode is born in the form of eigenfunction through which the stability is changed. Then a procedure is formulated to compute the bifurcating mode by the method of harmonic balance. Application of bifurcating mode to forced vibrations is introduced.

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압전 비틀림 변환기의 진동특성 해석 (Vibration Characteristics of Piezoelectric Torsional Transducers)

  • 권오수;김진오
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.1280-1285
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    • 2000
  • The paper deals with a theoretical study on the vibrational characteristics of piezoelectric torsional transducers. The differential equations of piezoelectric torsional motion have been derived in terms of the circumferential displacement and the electric potential. Applying mechanical and electrical boundary conditions has yielded the characteristic equations of natural vibration in several transducer types. Numerical results have clarified the effect of the piezoelectric phenomenon on the mechanical resonance and the effect of the elastic block of a Langevin-type transducer on the natural frequency.

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셸 구조물의 중고주파 진동 파워흐름해석 (Power Flow Analysis for Medium-to-High Frequency Vibration of Shell Structures)

  • 박도현;김일환;홍석윤;길현권
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 춘계학술대회논문집
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    • pp.1177-1184
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    • 2002
  • In this paper, power flow analysis method on the various types of thin shell has been developed to solve vibrational Problems in the medium to high frequency ranges. Energy governing equations have been derived both for out-of plane and in-plane waves in thin shell. These results have been numerically applied to predict the vibrational energy density and intensity distributions of cylindrical, spherical and doubly-curved shells.

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항공기 구조물의 동적 거동 시험/해석 절차 (An Integrated Approach to the Dynamic Testing of Aerospace Structures)

  • 이상엽
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.348-357
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    • 2006
  • Ground Vibration Tests (GVT) are needed on au new aircraft types and as part of certification. Its first objective is to verify models used for the calculation and prediction of the dynamic behavior of the structure. The main objectives of this paper are to introduce 'the integrated approach of dynamic testing for aerospace structure' in detail and 'The research projects in which LMS participated in aerospace structural dynamic area'

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