In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration(VIV)responses,the experimental study on VIV of bond umbilical cable(BUC)and un-bond umbilical cable(UBUC)was c...In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration(VIV)responses,the experimental study on VIV of bond umbilical cable(BUC)and un-bond umbilical cable(UBUC)was carried out in an experimental tank.A current generator in the laboratory simulated the uniform current,and the current velocities were observed in real time by using a Doppler Velocimeter.In addition,different sizes of top tension were applied to the umbilical cable model.The VIV responses of the umbilical cable model were measured by using Fiber Bragg grating(FBG)strain sensors.The displacement responses of umbilical cable model were reconstructed based on the experimental strain data processed by modal superposition method.In this paper,the traveling wave characteristics,the spatial-temporal distribution characteristics of frequency and fatigue damage of the BUC and UBUC under VIV are studied.The experimental results show that there are obvious differences between BUC and UBUC in the response characteristics of VIV.The UBUC appears the traveling wave sooner than BUC,but its standing wave characteristics are more obvious than those of BUC at high velocities.Compared with BUC,the spatial-temporal distribution of UBUC frequencies appears wide-band distribution sooner,but has narrower bandwidth in the"lock-in"state.The level of fatigue damage of BUC was approximately the same as that of UBUC.展开更多
Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field. The severe ocean environment makes great challenges to umbilical maintenance and repair work. ...Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field. The severe ocean environment makes great challenges to umbilical maintenance and repair work. Damaged umbilical is usually recovered for the regular operation of the offshore production system. Analysis on cables in essence is a two-point boundary problem. The tension load at the mudline must be known first, and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation. The recovery analysis also involves umbilical- soil interaction and becomes more complicated. Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed. The analysis results provide a theoretical reference for offshore on-deck operation.展开更多
This paper proposes a geometrically exact formulation for three-dimensional static and dynamic analyses of the umbilical cable in a deep-sea remotely operated vehicle(ROV) system. The presented formulation takes acc...This paper proposes a geometrically exact formulation for three-dimensional static and dynamic analyses of the umbilical cable in a deep-sea remotely operated vehicle(ROV) system. The presented formulation takes account of the geometric nonlinearities of large displacement, effects of axial load and bending stiffness for modeling of slack cables. The resulting nonlinear second-order governing equations are discretized spatially by the finite element method and solved temporally by the generalized-a implicit time integration algorithm, which is adapted to the case of varying coefficient matrices. The ability to consider three-dimensional union action of ocean current and ship heave motion upon the umbilical cable is the key feature of this analysis. The presented formulation is firstly validated, and then three numerical examples for the umbilical cable in a deep-sea ROV system are demonstrated and discussed, including the steady configurations only under the action of depth-dependent ocean current, the dynamic responses in the case of the only ship heave motion, and in the case of the combined action of the ship heave motion and ocean current.展开更多
An integrated hydrodynamics and control model to simulate tethered underwater robot system is proposed. The governing equation of the umbilical cable is based on a finite difference method, the hydrodynamic behaviors ...An integrated hydrodynamics and control model to simulate tethered underwater robot system is proposed. The governing equation of the umbilical cable is based on a finite difference method, the hydrodynamic behaviors of the underwater robot are described by the six-degrees-of-freedom equations of motion for submarine simulations, and a controller based on the fuzzy sliding mode control(FSMC) algorithm is also incorporated. Fluid motion around the main body of moving robot with running control ducted propellers is governed by the Navier–Stokes equations and these nonlinear differential equations are solved numerically via computational fluid dynamics(CFD) technique. The hydrodynamics and control behaviors of the tethered underwater robot under certain designated trajectory and attitude control manipulation are then investigated based on the established hydrodynamics and control model. The results indicate that satisfactory control effect can be achieved and hydrodynamic behavior under the control operation can be observed with the model; much kinematic and dynamic information about tethered underwater robot system can be forecasted, including translational and angular motions of the robot, hydrodynamic loading on the robot, manipulation actions produced by the control propellers, the kinematic and dynamic behaviors of the umbilical cable. Since these hydrodynamic effects are fed into the proposed coupled model, the mutual hydrodynamic influences of different portions of the robot system as well as the hydrological factors of the undersea environment for the robot operation are incorporated in the model.展开更多
基金the Natural Science Foundation of Shandong Province(Grant No.2018GHY115045)the National Natural Science Foundation of China(Grant Nos.51979257 and 51709161).
文摘In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration(VIV)responses,the experimental study on VIV of bond umbilical cable(BUC)and un-bond umbilical cable(UBUC)was carried out in an experimental tank.A current generator in the laboratory simulated the uniform current,and the current velocities were observed in real time by using a Doppler Velocimeter.In addition,different sizes of top tension were applied to the umbilical cable model.The VIV responses of the umbilical cable model were measured by using Fiber Bragg grating(FBG)strain sensors.The displacement responses of umbilical cable model were reconstructed based on the experimental strain data processed by modal superposition method.In this paper,the traveling wave characteristics,the spatial-temporal distribution characteristics of frequency and fatigue damage of the BUC and UBUC under VIV are studied.The experimental results show that there are obvious differences between BUC and UBUC in the response characteristics of VIV.The UBUC appears the traveling wave sooner than BUC,but its standing wave characteristics are more obvious than those of BUC at high velocities.Compared with BUC,the spatial-temporal distribution of UBUC frequencies appears wide-band distribution sooner,but has narrower bandwidth in the"lock-in"state.The level of fatigue damage of BUC was approximately the same as that of UBUC.
基金financially supported by the National Natural Science Foundation of China (Grant No. 41272323)the Program for New Century Excellent Talents in University (Grant No. NCET-11-0370)
文摘Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field. The severe ocean environment makes great challenges to umbilical maintenance and repair work. Damaged umbilical is usually recovered for the regular operation of the offshore production system. Analysis on cables in essence is a two-point boundary problem. The tension load at the mudline must be known first, and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation. The recovery analysis also involves umbilical- soil interaction and becomes more complicated. Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed. The analysis results provide a theoretical reference for offshore on-deck operation.
基金financially supported by the National High Technology Research and Development Program of China(863 Program,Grant No.2008AA09Z201)
文摘This paper proposes a geometrically exact formulation for three-dimensional static and dynamic analyses of the umbilical cable in a deep-sea remotely operated vehicle(ROV) system. The presented formulation takes account of the geometric nonlinearities of large displacement, effects of axial load and bending stiffness for modeling of slack cables. The resulting nonlinear second-order governing equations are discretized spatially by the finite element method and solved temporally by the generalized-a implicit time integration algorithm, which is adapted to the case of varying coefficient matrices. The ability to consider three-dimensional union action of ocean current and ship heave motion upon the umbilical cable is the key feature of this analysis. The presented formulation is firstly validated, and then three numerical examples for the umbilical cable in a deep-sea ROV system are demonstrated and discussed, including the steady configurations only under the action of depth-dependent ocean current, the dynamic responses in the case of the only ship heave motion, and in the case of the combined action of the ship heave motion and ocean current.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.11372112 and 10772068)
文摘An integrated hydrodynamics and control model to simulate tethered underwater robot system is proposed. The governing equation of the umbilical cable is based on a finite difference method, the hydrodynamic behaviors of the underwater robot are described by the six-degrees-of-freedom equations of motion for submarine simulations, and a controller based on the fuzzy sliding mode control(FSMC) algorithm is also incorporated. Fluid motion around the main body of moving robot with running control ducted propellers is governed by the Navier–Stokes equations and these nonlinear differential equations are solved numerically via computational fluid dynamics(CFD) technique. The hydrodynamics and control behaviors of the tethered underwater robot under certain designated trajectory and attitude control manipulation are then investigated based on the established hydrodynamics and control model. The results indicate that satisfactory control effect can be achieved and hydrodynamic behavior under the control operation can be observed with the model; much kinematic and dynamic information about tethered underwater robot system can be forecasted, including translational and angular motions of the robot, hydrodynamic loading on the robot, manipulation actions produced by the control propellers, the kinematic and dynamic behaviors of the umbilical cable. Since these hydrodynamic effects are fed into the proposed coupled model, the mutual hydrodynamic influences of different portions of the robot system as well as the hydrological factors of the undersea environment for the robot operation are incorporated in the model.