• 제목/요약/키워드: Whirling process

검색결과 13건 처리시간 0.017초

5패드 틸팅 패드 베어링의 설계 조건 변화가 소형 가스터빈의 횡진동 특성에 미치는 영향 (Effects of Design Conditions in Five Pad Tilting Pad Bearing on the Lateral Vibration Characteristics of Small Gas Turbine)

  • 하진웅;명지호;석진익;이안성;김영철
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2011년도 춘계학술대회 논문집
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    • pp.425-432
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    • 2011
  • In tilting pad bearing design process, the selection of the proper configuration type of either a Load-Between-Pad (LBP) or Load-On-Pad (LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a 5 pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by the its asymmetric dynamic properties.

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로터-베어링 시스템의 훨링속도 해석을 위한 유한요소 정식화 (Finite Element Formulations of the Rotor-Bearing System for Whirl Speed Analysis)

  • 윤성호
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2007년도 정기 학술대회 논문집
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    • pp.625-630
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    • 2007
  • This paper accounts for derivations and formulations of the finite element dynamic equation of the rotor-bearing system to analyze its whirling speed. It turns out to be a different form from previous researcher's because of different successive sequences of Euler angles. Correspondingly the adoption of other rotation tensor will be needed for a consistent derivation of the dynamic equation. The process of its finite element formulation with consistent mass matrix and gyroscopic matrix involves a general definition of the modal analysis or the Eigen analysis for the damped system in the inertial frame and rotating frame, respectively.

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한국 유방암 여성들의 유방재건술에 관한 의사결정 경험 (Decision Making Experience on Breast Reconstruction for Women with Breast Cancer)

  • 이명선;정우정;박은영;권은진;김해진;서지영
    • 대한간호학회지
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    • 제46권6호
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    • pp.894-904
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    • 2016
  • Purpose: The purpose of this study was to explore decision making experiences of Korean women with breast cancer who underwent breast reconstruction with/after a mastectomy. Methods: Data were collected during 2015-2016 through individual in-depth interviews with 10 women who had both mastectomy and breast reconstruction, and analyzed using phenomenological method to identify essential themes on experiences of making a decision to have breast reconstruction. Results: Five theme clusters emerged. First, "expected loss of sexuality and discovery of autonomy" illustrates various aims of breast reconstruction. Second, "holding tight to the reputation of doctors amid uncertainty" specifies the importance of a trust relationship with their physician despite a lack of information. Third, "family members to step back in position" describes support or opposition from family members in the decision making process. Fourth, "bewilderment due to the paradox of appearance-oriented views" illustrates paradoxical environment, resulting in confusion and anger. Lastly, "decision to be made quickly with limited time to oneself" describes the crazy whirling process of decision making. Conclusion: Findings highlight aims, worries, barriers, and facilitators that women with breast cancer experience when making a decision about breast reconstruction. Deciding on breast reconstruction was not only a burden for women in a state of shock with a diagnosis of breast cancer, but also an opportunity to decide to integrate their body, femininity, and self which might be wounded from a mastectomy. These findings will help oncology professionals provide effective educational counselling before the operation to promote higher satisfaction after the operation.