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웨이블릿 교차상관관계를 이용한 변형체 선박의 휘핑 응답 식별

Identification of Whipping Response using Wavelet Cross-Correlation

  • 김유일 (인하대학교 공과대학 조선해양공학과) ;
  • 김정현 (서울대학교 공과대학 조선해양공학과) ;
  • 김용환 (서울대학교 공과대학 조선해양공학과)
  • Kim, Yooil (Department of Naval Architecture and Ocean Engineering, College of Engineering, INHA University) ;
  • Kim, Jung-Hyun (Department of Naval Architecture and Ocean Engineering, College of Engineering, Seoul National University) ;
  • Kim, Yonghwan (Department of Naval Architecture and Ocean Engineering, College of Engineering, Seoul National University)
  • 투고 : 2013.10.14
  • 심사 : 2014.02.05
  • 발행 : 2014.04.20

초록

Identification of the whipping response out of the combined wave-vibration response of a flexible sea going vessel is one of the most interesting research topic from ship designer's point of view. In order to achieve this goal, a novel methodology based on the wavelet cross-correlation technique was proposed in this paper. The cross-correlation of the wavelet power spectrum averaged across the frequency axis was introduced to check the similarity between the combined wave-vibration response and impulse response. The calculated cross-correlation of the wavelet power spectrum was normalized by the auto-correlation of the each spectrum with zero time lag, eventually providing the cross-correlation coefficient that stays between 0 and 1, precisely indicating the existence of the impulse response buried in the combined wave-vibration response. Additionally, the weight function was introduced while calculating the cross-correlation of the two spectrums in order to filter out the signal of lower frequency so that the accuracy of the similarity check becomes as high as possible. The validity of the proposed methodology was checked through the application to the artificially generated ideal combined wave-vibration signal, together with the more realistic signal obtained by running 3D hydroelasticity program WISH-Flex. The correspondence of the identified whipping instances between the results, one from the proposed method and the other from the calculated slamming modal force, was excellent.

키워드

참고문헌

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