응답면 근사 기법을 적용한 계류선의 준동적 해석 모델
Quasi-Dynamic Analysis Model of Mooring Lines Using Response Surface Approximation Method
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초록
이 논문에서는 부유식 구조체의 계류선에 작용하는 장력을 계산함에 있어서 동적 효과를 고려할 수 있는 준동적 계류선 해석 방법을 제안하였다. 준동적 계류선 해석 방법은 매 시간 단계에서 계류선의 탄성 현수선 해석해에 기반한 정적 장력을 계산한 후, 준동적 장력 계수를 적용해 속도와 가속도에 따른 항력 및 관성력의 영향을 반영하는 방법이다. 제안하는 방법은 정적 탄성 현수선 해석해를 구할 때 계산 효율성을 높이기 위해 응답면 기법을 도입하고, 수평 및 수직 방향의 동적 계수를 결합하여 준동적 장력 계수를 결정하는 새로운 방법을 제안하였다. 제안된 모델은 계류된 바지선의 운동 해석을 통해 검증하였으며, 다양한 파 조건에서 동적, 준정적, 준동적 모델을 비교한 결과, 제안된 준동적 모델은 상대적으로 계류선의 동적 효과가 큰 주파수 대역에서 동적 모델과 유사한 장력 응답을 도출할 수 있음을 확인하였다.
Abstract
This paper proposes a quasi-dynamic mooring line analysis method that accounts for dynamic effects when calculating the tension on the mooring lines of floating structures. The quasi-dynamic approach calculates the static tension of the mooring line at each time step using the elastic catenary solution and then applies a quasi-dynamic tension coefficient to account for the drag and inertial forces due to velocity and acceleration. To improve the computational efficiency of determining the static elastic catenary solution, a response surface method was employed. Additionally, a new technique was introduced to determine the quasi-dynamic tension coefficient by combining the dynamic coefficients in the horizontal and vertical directions. The proposed model was validated through a motion analysis of a moored barge by comparing the results of the dynamic, quasi-static, and quasi-dynamic models under various wave conditions. The quasi-dynamic model demonstrated tension responses similar to the responses of the dynamic model, particularly in the frequency ranges where the dynamic effects on the mooring line are significant.
참고문헌 (16)
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