• 한국소음진동공학회논문집
• /
• 제12권12호
• /
• pp.956-963
• /
• 2002

In a recent construction industry, cable supported structures such as a cable-stayed bridge or space stadium have been increasingly constructed according to rapidly upgrade their related technologies. Generally stay cables as a critical member need to be rearranged for being satisfied with design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted on existing stay cables. In this study, cable vibration tests were tarried out to evaluate the cable tension forces comparing with theoretical and practical formulas. Using the measured frequencies obtained from free vibration and Impulsive tests, an accuracy of the estimated tension forces is confirmed according to use the first single mode only or higher multiple modes.

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권2호
• /
• pp.217-224
• /
• 2014

We have developed the novel device that can extract energy from ocean waves utilizing the heaving motion of a floating mass. The major components of the energy converter are: a floater, a counterweight, a cable, a driving pulley, two idler pulleys, a ratchet, and a generator. The device generates power through the tension force in the cable and the weight difference between the floater and the counterweight. When the system is at static free condition, the tension in the cable is equal to the weight of the counterweight which is minimum. Therefore it is desirable to keep the counterweight lighter than the floater. However, experiments show that during the rise of the water level, the torque generated by weight of the counterweight is insufficient to rotate the driving pulley which causes the cable on the floater side to slack. The proposed application of the tension pulley rectifies these problems by preventing the cable from becoming slack when the water level rises. In this paper, the dynamics model is modified to incorporate the dynamics of the tension pulley. This has been achieved by first writing the dynamical equations for the tension pulley and the energy converter separately and combining them later. This paper investigates numerically the effect of the tension pulley on various physical quantities such as the cable tension, the floater displacement, and the floater velocity. Results obtained indicate that this application is successful in suppressing large fluctuations of the cable tension.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 춘계학술대회논문집
• /
• pp.121-126
• /
• 2002

In a recent construction industry, cable supported structures such as a cable-stayed bridge or space stadium have been increasingly constructed. Generally the stay cables as a critical member should be adjusted to be satisfied with the design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted to the existing stay cables. In this study, cable vibration tests were carried out to estimate the cable tension forces comparing with theoretical and practical formulas. From the measured frequencies obtained from free vibration and impulsive tests, the accuracy of 1he estimated tension forces is confirmed according to use only the first single mode or higher multiple modes.

• 한국구조물진단유지관리공학회 논문집
• /
• 제12권2호
• /
• pp.113-120
• /
• 2008

본 연구는 케이블의 초기길이를 조절하여 케이블 배치가 끝난 후 발생한 장력과 목표장력을 서로 일치시킬 수 있는 초기길이 수정법을 제시하였다. 케이블 지지교량에 대해 정확한 초기길이를 결정하기 위하여 본 연구는 탄성현수선 케이블 요소를 사용하였다. 검증 예제를 해석한 결과 목표장력에 따라 이를 만족하는 초기길이를 결정할 수 있었고 케이블 교량에 대해서도 만족할 만한 결과를 얻을 수 있었다. 따라서 초기길이를 수정하는 본 연구의 방법을 이용하면 목표장력을 도입할 수 있을 것으로 판단된다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제9권3호
• /
• pp.129-138
• /
• 2005

본 논문은 사장교에서 모니터링 시스템을 통해 획득한 가속도 자료를 이용하여 케이블 관리기준 장력을 결정하기 위한 방법을 제시한다. 현재 한국의 많은 장대교량에 모니터링 시스템이 설치되어 있다. 모니터링 시스템은 교량의 이상현상이나 손상을 진단하고 관리주체에 경고하기 위해 설치된다. 사장교에 있어서는 그 기하학적인 형상 때문에 케이블 장력이 교량 이상징후의 중요한 지시가 될 수 있다. 만약 케이블 장력관리치가 너무 높거나 또는 너무 낮게 설정되면, 모니터링 시스템은 교량의 이상징후를 적절하게 경고하지 못할 것이다. 일반적으로, 관리치는 경험이나 공학적 판단에 의해 결정된다. 그러나 본 논문에서는 케이블 장력에 대한 확률분포모형과 신뢰성 해석에 기초한 새로운 케이블 장력관리치 설정에 대한 방법을 제시한다. 제안된 방법은 적용성 검토를 위하여 실제 콘크리트 사장교에 적용되었다.

• 문화기술의 융합
• /
• 제9권4호
• /
• pp.633-638
• /
• 2023

본 연구에서는 공용중인 강철도 복합교량의 케이블 장력변화가 철도교량 상 자갈궤도의 궤도틀림에 미치는 영향을 해석적으로 분석하였다. 케이블 장력에 대한 설계 및 해석결과 비교 결과, 약 3% 미만의 차이가 나타나 해석모델링은 설계조건을 잘 반영하는 것으로 분석되었다. 또한 현장측정결과와 해석 케이블 장력과 비교하여 해석모델링의 적정성을 입증하였다. 케이블 장력 변화를 변수로 설정하여 강철도 복합교량의 궤도틀림을 해석적으로 분석하였다. 분석결과, 전체 및 편측 케이블 장력변화는 궤도틀림 항목 중 고저틀림에 직접적인 영향을 미치는 것으로 분석되었다. 또한 케이블 위치와 근접한 구간에서 궤도틀림의 변화가 발생하는 것으로 나타났다. 케이블 장력 변화는 수평방향에 의한 궤도틀림(방향틀림 및 궤간틀림)보다는 연직방향과 직접적인 상관성을 갖는 궤도틀림(고저틀림 및 수평틀림)에 보다 직접적인 영향을 미치는 것으로 분석되었다.

• Structural Engineering and Mechanics
• /
• 제50권1호
• /
• pp.37-52
• /
• 2014

The accurate determination of cable tension is important to the monitoring of the condition of a cable-stayed bridge. When applying a vibration-based formula to identify the tension of a real cable under sag, stiffness and boundary conditions, the resulting error must not be overlooked. In this work, by resolving the implicit frequency function of a real cable under the above conditions numerically, indirect methods of determining the cable force and a method to calculate the corresponding cable mode frequency are investigated. The error in the tension is studied by numerical simulation, and an empirical error correction formula is presented by fitting the relationship between the cable force error and cable parameters ${\lambda}^2$ and ${\xi}$. A case study on two real cables of the Shanghai Changjiang Bridge shows that employing the method proposed in this paper can increase the accuracy of the determined cable force and reduce the computing time relative to the time required for the finite element model.

• 한국안전학회지
• /
• 제31권5호
• /
• pp.28-34
• /
• 2016

When a electric power cable is installed in the air for newly or exchanged working, it is necessary at all time to hold a constant tension for an overhead power cable. And also a pendanted power cable is an extreme job to have work in a high sky. For this reason, the objective of this paper developments working robot for preventing disaster that tension of cable installed automatically power cable to hold a constant. So the working robot works at all the time two tasks for mobil and tension it come into a inference between two tasks, control is difficult. Control methode needs to suppress inference of two tasks. In this paper, for installation of overhead power cable, the scheme and control methode of working robot is presented. the robot work at a same time tow tasks that have hold a constant tension of the power cable and move a constant place while unfasten a winding cable at a drum on a chassis. Working robot consist of three parts with mobile system, tension system and control part. As it is applied the feedback/feedforward control, methode of hybrid control is established to suppress that interference come into between two tasks. The simulation programs is made out using models of mobil and tension system, and a proposed controllers. In accordance with simulation, the model of each systems is discussed to make out proper. And also parameters of controllers is selected a suitable value and the driving performance of robot is evaluated.

• 문화기술의 융합
• /
• 제8권4호
• /
• pp.407-413
• /
• 2022

본 연구에서는 약 3년간의 장기계측을 바탕으로 공용중인 복층 교량인 상부 도로교의 신축이음 신축량과 하부 철도교의 케이블 장력 간의 상관관계를 입증함으로서 온도변화에 따른 케이블 장력 평가 경험식을 제안하였다. 본 연구에서 제안한 케이블별 장력 평가 경험식을 이용한 장력 예측결과는 진동법을 이용한 장력과 3% 이내로 잘 일치하는 것으로 나타나 공용중인 케이블의 장력 예측 및 평가에 실험적인 기법인 진동법과 함께 적용이 가능할 것으로 판단되었다. 본 연구에서 제안한 신축량 경험식으로 산출한 추정온도를 케이블 경험식에 적용한 결과, 현장시험 진동법 측정결과와 비교시 높은 신뢰수준을 확보할 수 있을 것으로 분석되었다. 따라서 본 연구에서 제안한 추정온도를 반영한 장력 평가 경험식은 향후 기후변화에 따른 케이블의 장력 예측 및 유지관리방안 수립에 활용될 수 있을 것으로 판단된다.

• Structural Monitoring and Maintenance
• /
• 제10권3호
• /
• pp.261-281
• /
• 2023

Magnetic flux sensors are commonly used in monitoring the cable force, but the application of the sensors in large diameter non-closed Galfan cables, as those adopted in Yueqing Gymnasium which is located in Yueqing City, Zhejiang Province, China and is the largest span hybrid space structure in the world, is seldom done in engineering. Based on the construction of Yueqing Gymnasium, this paper studies the cable tension monitoring using the magnetic flux method across two stages, namely, the pre-calibration stage before the cable leaves the rigging factory and the field tension formation stage of the cable system. In the pre-calibration stage in the cable factory, a series of 1:1 full-scale comparative tests were carried out to study the feasibility and relability of this kind of monitoring method, and the influence on the monitoring results of charging and discharging voltage, sensor location, cable diameter and fitting method were also studied. Some meaningful conclusions were obtained. On this basis, the real-time cable tension monitoring system of the structure based on the magnetic flux method is established. During the construction process, the monitoring results of the cables are in good agreement with the data of the on-site pressure gauge.The work of this paper will provide a useful reference for cable force monitoring in the construction process of long-span spatial structures.