• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.601-604
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• 2002

In this paper bolt-tightened Langevin type vibrator was designed using longitudinal-torsional vibration. These two vibrations make rotary displacement at the end of the vibrator. ANSYS was used to determine shape and dimension of the vibrator in addition to resonant frequency, displacement and stress distribution. This kind of vibrator can be applied for a brakeless and gearless rotary motor which has high torque at low speed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1159-1164
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• 2006

Torsional vibration is an important vibration mode when shafts, cylinders and pipes are considered. However, the modal testing of torsional vibrations is not an easy job to carry out because of the lack of proper transducers. This work presents a new torsional vibration transducer based on the magnetostrictive principle and its application to torsional modal testing. The transducer is so designed as to generate/measure only torsional vibrations excluding other vibration modes such as longitudinal and bending vibrations. The transducer is composed of ferromagnetic patches bonded to a test structure, permanent magnets, and a solenoid. Though patches and magnets are bonded to a structure, torsional vibrations are generated and measured wirelessly by a solenoid encircling a test structure. The proposed transducer works even at considerably high frequencies, say, tens of kilohertz. Furthermore, the transducer can be manufactured at a low price. To check the performance of the proposed method, the torsional modal testing on a hollow aluminum shaft was conducted. The results, such as eigenfrequencies, obtained by the proposed transducer agreed favorably with theoretical results.

• 한국소음진동공학회논문집
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• 제16권8호
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• pp.879-885
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• 2006

Torsional vibration is an important vibration mode when shafts, cylinders and pipes are considered. However, the modal testing of torsional vibrations is not an easy task to carry out because of the lack of proper transducers. This work presents a new torsional vibration transducer based on the magnetostrictive principle and its application to torsional modal testing. The transducer is so designed as to generate/measure only torsional vibrations excluding other vibration modes such as longitudinal and bending vibrations. The transducer is composed of ferromagnetic patches bonded to a test structure, permanent magnets, and a solenoid. Though patches and magnets are bonded to a structure, torsional vibrations are generated and measured wirelessly by a solenoid encircling a test structure. The proposed transducer works even at considerably high frequencies, say, tens of kilohertz. Furthermore, the transducer can be manufactured at a low price. To check the performance of the proposed method, the torsional modal testing on a hollow aluminum shaft was conducted. The results, such as eigenfrequencies, obtained by the proposed transducer agreed favorably with theoretical results.

• Journal of Advanced Marine Engineering and Technology
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• 제22권5호
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• pp.626-634
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• 1998

Controllable pitch propeller(CPP) is usually adopted for easy and effective engine controls of a ship in a port. Unfortunately the torsional vibration may occur by a certain variation of engine torque and the major resonance peak may exist within the maximum continuous rating(MCR) In these cases an additional stress concentration on the oil passages such as longitudinal slots notches and circular holes of an oil distributor shaft(ODS) occurs by the torsional vibration of the CPP shaft. In this paper an analysis for the fatigue limit of an ODS system of the 5S70MC engine in a crude oil carrier is done by applying FEM and empirical formulas. Furthermore the additional stress on the ODS is investigated by analyzing the torsional vibration of the shaft system and a control method in which a tuning damper is adopted is introduced in the case of the additional stress exceeds the fatigue limit. The validity of analysis method is verified by comparing the results acquired by an actual measurement of the vibratory torque for the above ODS

• 대한토목학회논문집
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• 제31권3A호
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• pp.261-267
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• 2011

본 연구는 부착식 PSC 텐던에 도입된 긴장응력이 종진동 거동에 미치는 메커니즘을 규명한다. 텐던의 종방향 직선변형과 비틀림변형은 상호 연동하여 거동하고, 텐던에 도입된 긴장응력은 축강성과 비틀림강성에 영향을 미친다. 그러므로 텐던의 탄성파 속도를 계측함으로써 텐던에 도입된 긴장응력을 추정 할 수 있다. 이는 텐던의 탄성파속도가 축강성과 비틀림강성의 함수이기 때문에 가능하다. 도입 긴장력이 다른 6개의 PSC 보 시험체에 대한 종진동 실험결과를 이용하여 텐던의 종진동 특성과 도입 긴장응력 사이의 역학적 메커니즘이 검증되었다. 이를 위하여, 탄성파 속도로부터 텐던의 시스템 강성을 추정할 수 있는 시스템인식 이론이 적용 되었다. 추정 결과는 기존 문헌의 연구결과와 비교 검토되었다.

• 대한조선학회논문집
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• 제32권2호
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• pp.103-107
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• 1995

선체거더의 종진동 현상은 60년대에 이미 조사된 바 있으나 기존 선박들에서는 종방향 기진력이 작았기 때문에 선체 종진동 현상이 거의 나타나지 않았다. 그러나 80년대 중반이후의 대형 저속디젤엔진 추진선에서는 추진축계 비틂 공진점에서 연성되어 작용하는 축계 종방향 기진력에 의하여 선체전체의 종진동이 유발될 수도 있다. 본 연구에서는 73,000톤 산적화물선에서 감지된 선체거더의 종진동 현상을 실선계측 및 해상기진기 실험 그리고 유한요소 해석방법으로 분석하였다. 분석결과 이러한 선체 종진동 현상은 Over-critical 축계 시스템을 갖춘 선박에서만 축계 종방향 기진력에 의해 나타날 수가 있으며 그 중에서도 주기관의 연속 사용금지구역(barred range)이 설정되지 않은 선박의 경우엔 하중조건에 따라 저속 입출항 운항시 선루를 포함한 선체에 심한 중진동이 발생될 수 있슴이 판명되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제21권3호
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• pp.256-266
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• 1997

The authors apply the transfer influence coefficient method to the 3. dimensional vibration analysis of beam with multi - joints and formulate a general algorithm to analyse the longitudinal, flexural and torsional coupled forced vibration. In this paper, a structure which is mainly found in the robot arms, cranes and so on, has some crooked parts, subsystems and joints, but has no closed loop in this system. It is modeled as the beam of a distributed mass system with massless translational, rotational and torsional springs in each node, and joint elements of release or roll at node which the displacement vector is discontinuous. The superiority of the present method to the transfer matrix method in the computation accuracy was confirmed from the numerical computation results. Moreover, we confirmed that boundary and intermediate conditions could be controlled by varying the values of the spring constants.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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• pp.203-209
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• 1996

The authors apply the transfer influence coefficient method to the 3-dimensional vibration analysis of beam with multi-joints and formulate a general algorithm to analysis the longitudinal, flexural and torsional coupled forced vibration. In this paper, a structure, which is mainly founded in the robot arms, cranes and so on, has some crooked parts, subsystems and joints but has no closed loop in this system. It is modeled as the beam of a distributed mass system with massless translational, rotational and torsional springs in each node, and joint elements of release or roll at which node the displacement vector is discontinuous. The superiority of the present method to the transfer matrix method in the computation accuracy was confirmed from the numerical computation results. Moreover, we confirmed that boundary and intermediate conditions could be controlled by varying the values of the spring constants.

• Journal of Advanced Marine Engineering and Technology
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• 제18권5호
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• pp.68-77
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• 1994

The authors apply the transfer influence coefficient method to the 3-dimensional vibration analysis of beam with multi-joints and formulate a general algorithm to analysis the longitudinal, flexural and torsional coupled free vibration. In this paper, the structure, which is mainly founded in the robot arms, cranes and so on, has some crooked parts, subsystems and joints but has no closed loop in this system. It is modeled as the beam of a distributed mass system with massless translational, rotational and torsional springs in each node, and joint elements of release or roll at which node the displacement vector is discontinuous. The superiorty of the present method to the transfer matrix method in the computation accuracy was confirmed by the numerical computation results. Moreover, we confirmed that boundary and intermediate conditions could ve controlled by varying the values o the spring constants.

• 대한조선학회논문집
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• 제35권3호
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• pp.71-78
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• 1998

최근 선박의 디젤주기관은, 선반의 에너지 절약을 도모하기 위하여 장행정 소수실린더 저속회전화 추세에 있기 때문에 기전력이 커지고 있다. 이러한 결과로 추진축계에 비틂진동이 크게 발생함으로 인하여 축계의 과잉 비틂진동응력과 프로펠러의 추력변동이 크게 야기되면서 추력변동은 축계와 상부구조물의 종진동을 유발시키고 있다. 이와관련하여 추진축계의 기진력이 확정적이라는 가정하에서 확정적 연성강제진동에 관한 연구가 진행되어 왔으며, 또한 축계기진력의 변화성을 고려하여 축계 비틂강제진동에 대한 확률적 해석이 수행되어 왔다. 본 연구에서는 디젤기관 및 프로펠러의 기진력의 확률변수를 동시에 고려하여, 추진축계의 종 비틂연성진동의 확률적 해석에 대한 새로운 방법을 제시하였다. 확률적 해석에 응답면이론과 Monte-Carlo시뮬레이션법이 적용되었다. 본 해석방법의 유용성을 확인하기위하여 시산대상선의 추진축계에 대한 일련의 확정적 및 확률적 수치계산을 각각 수행하고, 그 계산결과를 서로 비교 검토하여 본 결과, 본 해석방법의 유용성이 확인되었다.