• 대한조선학회지
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• 제23권4호
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• pp.1-10
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• 1986

A container ship, due to wide hatch openings, has characteristics of poor torsional rigidity, strong coupling of horizontal-torsional modes and significant discontinuity in the longitudinal variation of hull sections. In the mathematical formulation of the problem the hull is modeled as a beam and the transfer matrix method is utilized. The cross decks between cargo hatch opening are separated from the main hull and regarded as equivalent springs restraining torsion of hull. The effect of shear deformation of ship-side plating on torsion is taken into account in addition to St. Venant's and bending torsional rigidities. Compatibility requirements at cross section discontinuity are approximately considered. Developing the practical calculation procedure and the computer programs for application to an actual ship, some parametric studies on modeling methods of the cross deck, the compatibility condition, added-mass center etc. are out for the purpose of comparison.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.43-49
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• 1997

A rotating rigid disk, attached on a flexible shaft or supported by a torsional spring, experiences precessional whirling due to gyroscopic moment loading. It is well known in rotor dynamics area that, as the rotational speed increases, the precessional mode of the rotating rigid disk starts splitting into two: forward and backward precessional modes. On the other hand, it is also well known in disk vibration area that a rotating flexible disk also shows another kind of mode splitting phenomenon due to the rotation, resulting in forward and backward traveling waves. When rotating multiple flexible disks are coupled in vibration with the supporting Flexible shaft, the associated mode splitting should be compatible with the two seemingly different vibration analysis methods. This paper investigates the possibility of fusing the precessional and traveling wave mode splittings so that the bending coupled disk vibrations in HDD spindle systems can be better understood.

• 한국강구조학회 논문집
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• 제9권2호통권31호
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• pp.269-275
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• 1997

본 연구에서는 자정식 현수교 주탑의 내풍 안정성을 보기 위하여 주탑 모형 실험과 전교 모형 실험을 수행하고 그 결과를 분석하였다. 경사진 병렬 탑주를 가진 주탑의 경우에는 다양한 주파수대의 웨이크가 존재하므로 넓은 풍속대에서 진동이 발생한다는 사실을 확인하였다. 자정식 현수교의 경우에는 주형의 교축방향 지지조건에 따라 주탑 진동 모드가 매우 민감하게 변화하였다. 본 연구 대상 주탑은 면외 휨 모드와 비틈 모드의 고유진동수가 매우 근접해 있어서 넓은 범위의 풍속에서 연성진동이 발생하였다 주탑 진동을 완화하기 위한 공기역학적 수단으로 모서리 자르기를 시도하였는데, 탑주의 폭과 잘린 모서리의 비가 1/10일 때가 가장 효과적이었다.