• 한국음향학회지
• /
• 제41권6호
• /
• pp.680-690
• /
• 2022

일반적으로 배관에서 발생하는 진동은 배관을 파손시키는 문제를 넘어 배관 파손으로 유발되는 다른 위험한 문제의 원인이 된다. 배관 진동의 원인 분석과 이를 줄이기 위한 수많은 연구들이 존재하는데, 그 중 마찰 지지대를 이용한 배관 진동저감에 대한 연구가 소수 진행되고 있다. 하지만 마찰 지지대에 관한 연구들은 마찰 지지대 성능 예측과 평가에만 집중하였고, 지지대 설치 위치에 따라 달라지는 마찰 지지대의 효과는 고려하지 않았다. 따라서, 본 연구에서는 마찰 지지대의 설치 위치에 따른 배관 진동 저감 효과를 입증하고 전체 시스템의 진동을 줄이기 위한 마찰 지지대 위치 선정 방법을 제시한다. 설계단계에서 최적화 방법을 효과적으로 적용하기 위해 선형 해석으로만 마찰 지지대의 최적 위치를 예측하고, 설계된 마찰 지지대를 시간 영역 해석을 통해 방법론의 타당성을 입증하였다. 또한, 배관 시스템에서 마찰 지지대의 우수한 진동 저감 효과를 정량적으로 해석하여, 지지대 설치 위치를 예측하는 방법의 효용성을 증명하였다.

• 대한기계학회논문집A
• /
• 제31권2호
• /
• pp.190-196
• /
• 2007

A few intake stations have vibration problems caused by pumps, motors and pipes. The vibration transferred from pumps, motors and pipes excites building severely. Therefore, the crack is generated on building wall and people who work at intake station are damaged. In this paper, the vibration has been measured and analyzed for pumps, motors, pipes and building at intake station. Also, the cause of vibration is identified. Finally, the solution of structural vibration is established using the results of measurement.

• 소음진동
• /
• 제7권3호
• /
• pp.489-498
• /
• 1997

In this paper, chaotic motions of a curved pipe conveying oscillatory flow are theoretically investigated. The nonliear partial differential equation of motion is derived by Newton's method. The transformed nonlinear ordinary differential equation is a type of Hill's equation, which has the external and parametric excitation with a same frequency. Bifurcation curves of chaotic motion of the piping systems are obtained by applying Melnikov's method. Numerical simulations are performed to demonstrate theoretical results and show the strange attractor of the chaotic motion.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1994년도 추계학술대회논문집; 한국종합전시장, 18 Nov. 1994
• /
• pp.259-264
• /
• 1994

본 연구에서는 유체와 파이프간의 완전 연계성을 포함하는 유한요소모델을 유도하고 Runge-Kutta 알고리즘을 적용하기 위한 수치해석 기법을 개발하였다. 기존의 연구자들이 다룬 바 있는 문제들을 다루어 봄으로써 본 연구결과의 신빙성을 점검하였으며, 다른 연구자들이 사용해 온 파이프의 진동방정식에서는 무시해 온 유체에 의해 발생하는 힘들의 영향을 고찰하였다. 그 결과, 유체가 고속으로 흐를 때 이들의 영향을 무시할 수 없음을 알았다. 앞으로, 더 다양한 경계조건에 대한 연구와 좀 더 효율이 높은 수치해석 기법의 개발이 요구된다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 추계학술대회논문집
• /
• pp.1077-1082
• /
• 2004

It is well known that the pipe will be unstable if the fluid velocity is higher than critical velocity. But even if the velocity of the fluid below the critical velocity, resonance will be caused by pulsation of the fluid. So, many people has studied about the piping system vibration due to a fluid pulsation. But almost guess that fluid has only one hamonic pulsation. Actually, like this case is rare quite. So, in this paper, we consider the vibration analysis of a pipe conveying fluid with several harmonic pulsations and compare the result which considers one hamonic pulsation with the result which considers several harmonic pulsations. And we verify the result in time domain again.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1999년도 추계학술발표회요약집
• /
• pp.345.2-345
• /
• 1999

• 대한기계학회논문집B
• /
• 제39권2호
• /
• pp.199-206
• /
• 2015

본 연구에서는 인공신경망을 이용하여 배관이나 배관요소의 작동상태를 예측할 수 있는 진단방법을 제안한다. 입자영상유속계 기술을 이용하여 얻어진 배관의 검사부위의 진동에 의한 이동량을 인공신경망의 학습용으로 사용한다. 측정시스템은 카메라, 조명, 인공신경망이 탑재된 호스트컴퓨터로 구성된다. 구축된 모니터링시스템이 제대로 작동하는지 이미 알고 있는 진동원(2개의 휴대폰)에 대하여 적용하였다. 진동가속도의 최소값, 최대값, 평균값을 인공신경망의 학습에 사용해 본 결과, 평균값이 진동상태의 실시간 모니터링에 적합함을 확인하였다. 구축된 진단시스템은 실제 가스배관의 작동상태에 대하여 모니터링 가능함이 확인되었다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집A
• /
• pp.636-643
• /
• 2001

Interference between the crossover leg of the reactor coolant system (RCS) and the pipe whip restraints (PWR) has brought a degradation issue of the integrity of the Reactor Coolant System in Westinghouse type nuclear power plants (NPPs) of Korea. According to the gap Inspect ion carried out during planned overhaul (Year 2000), interference between the crossover leg and the PWR was found in each RCS loop. This plant has had the high vibration problem on the RC pump 'B'. The reason for the high vibration in the RC pump 'B' had been massively surveyed and it was found that the crossover leg of RCS contacted with the PWR in hot condition. Since the contact between the crossover leg and the PWR changes the dynamic characteristics of the piping system for the RCS, this is considered as one reason for the high vibration. And a possibility of overstress on the crossover leg due to the contact with the PWR should be evaluated. Through performing RCS integrity analyses, subsequent actions were initiated to increase the gap between those parts. As the results of the appropriate separation between two parts, it was reported that there was no unusual noise or vibration during plant heat-up. In this paper, the evaluations for the gap between the crossover leg and the PWR and the structural integrity due to loop binding is described.

• 한국압력기기공학회 논문집
• /
• 제16권1호
• /
• pp.37-41
• /
• 2020

The Nuclear containment building is a main safety-related structure that performs shielding and conservation functions to prevent highly radioactive materials from leakage to the outside environment in the case of various environmental conditions and postulated accidents. The containment building contains a reactor, steam generator, pressurizer, tank, reactor coolant system, auxiliary system and engineering safety system, and is designed so that highly radioactive materials above the limits specified in 10 CFR 100 do not escape to the outside environment in the case of LOCA(Loss of Coolant Accident) for instance. The containment metal liner plate(CLP) is a carbon steel plate with a nominal plate thickness of 6 mm, which functions as a mold for the wall and dome of the containment building when concrete is filled, fulfills airtightness to prevent leakage of seriously radioactive materials. In recent years, backside corrosion was found on the liner plate in some domestic nuclear power plants. The main cause of backside corrosion was unfilled concrete. In this paper, an inspection technique of assessing filling suitability for CLP backside concrete is developed. Results show that the validity of inspection technique for CLP backside concrete using vibration sensor is successfully verified.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제55권3호
• /
• pp.131-137
• /
• 2006

The secondary system of nuclear power plants consists of sophisticated piping systems operating in very aggressive erosion and corrosion environments, which make a piping system vulnerable to the wear and degradation due to the several chemical components and high flow rate (~10 m/sec) of the coolant. To monitor the wear and degradation on a pipe, the vibration signals are measured from the pipe with an accelerometer For analyzing the vibration signal the time-frequency analysis (TFA) is used, which is known to be effective for the analysis of time-varying or transient signals. To reduce the inteferences (cross-terms) due to the bilinear structure of the time-frequency distribution, an adaptive cone-kernel distribution (ACKD) is proposed. The cone length of ACKD to determine the characteristics of distribution is optimally selected through an adaptive algorithm using the normalized Shannon's entropy And the ACKD's are compared with the results of other analyses based on the Fourier Transform (FT) and other TFA's. The ACKD shows a better signature for the wear/degradation within a pipe and provides the additional information in relation to the time that any analysis based on the conventional FT can not provide.