Analysis and Calculation of Ocean Current Load and Wave Load on a Floating Crane under a Normal Working State

2015 ◽  
Vol 73 ◽  
pp. 48-53
Author(s):  
Fumin Zhu ◽  
Yuan Jiang ◽  
Wanli Li
Keyword(s):  
Ocean Current ◽  
Current Load ◽  
Wave Load ◽  
Floating Crane

scholarly journals Modeling of submarine initial pipe-laying process and its real-time semi-physical virtual reality system

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774773 ◽  
Author(s):  
Xiujun Xu ◽  
Liquan Wang ◽  
Zhen Li ◽  
Shaoming Yao ◽  
Xiaoming Fang
Keyword(s):  
Mathematical Model ◽  
Virtual Reality ◽  
Real Time ◽  
Physical Simulation ◽  
Ocean Current ◽  
Virtual Reality System ◽  
Wave Load ◽  
Engineering Project ◽  
Load Effects ◽  
The Mathematical Model

The mathematical model of the initial pipeline and cable process is created with regard to the ocean current load and wave load; and the mathematical model is solved by the numerical quasi-Newton method to investigate the effects of the current and wave load on the shape and force of the pipeline and cable during the initial pipe-laying process. On this basis, semi-physical simulation system is built to visualize the initial pipe-laying process. The simulation results are compared with OFFPIPE’s results to verify the mathematical model. The current and wave load effects on the shape and tension of the pipeline and cable are analyzed. This real-time virtual reality system will help engineering project in risk management and prediction as well as staff training, which is of vital significance for minimizing the risk of the actual pipe laying and improving the efficiency of the pipe-laying work.

Motion and Whiplash Effect of a Floating Crane Model und er Wave Load: Experiment

2020 ◽  
Vol 99 (sp1) ◽  
pp. 346
Author(s):  
Jiannan Zhou ◽  
Haiyuan Wang ◽  
Zhaobing Jiang
Keyword(s):  
Wave Load ◽  
Floating Crane ◽  
Whiplash Effect

A Method of Dynamic Modeling of a Large Floating Crane and its External Excitations

2010 ◽  
Vol 139-141 ◽  
pp. 2440-2445
Author(s):  
Qing Zhang ◽  
Jian Jie Zhang ◽  
Ji He ◽  
Yong Feng Li ◽  
Xian Rong Qin
Keyword(s):  
Wind Wave ◽  
Linear Method ◽  
Dominant Frequency ◽  
Global Coordinate System ◽  
Wave Loads ◽  
Wave Load ◽  
External Excitation ◽  
Lagrange’S Equation ◽  
Local Coordinates ◽  
Floating Crane

According to the characteristics of floating cranes, an affordable numerical method to model the floating cranes and the external excitations such as wind, wave and shimmy loads was proposed. Local coordinates modifying wind, wave and shimmy loads which are determined separately were combined in the global coordinate system according to the geometric positions. The spectra of wind loads and wave loads were converted into time domain separately according to the linear method, while a shimmy load is determined according to the Lagrange’s Equation. As an example, the external excitation caused by random wind, wave and shimmy loads on a 7500-ton giant floating crane were simulated, and the transient dynamic response was predicted and discussed. Focusing on the characteristics of structure of floating cranes, the research indicates that the dominant frequency of the wave load is low, as compared to wind and shimmy loads, and that the shimmy load is closely related to the environmental excitations such as wind and wave loads. The results also suggest that the transient response of the crane is mainly related to the shimmy load.

scholarly journals Hydrodynamic Load Analysis and Experimental Study of Grouting Clamp under Wave and Ocean Current

2020 ◽  
Vol 8 (7) ◽  
pp. 512
Author(s):  
Bo Zhang ◽  
Zhi-quan Shang ◽  
Tao Wang ◽  
Zhuo Wang
Keyword(s):  
Research Direction ◽  
Offshore Platform ◽  
Ocean Current ◽  
Load Force ◽  
Linear Wave ◽  
Wave Load ◽  
Safety And Reliability ◽  
Combined Action ◽  
Marine Engineering ◽  
Complex Sea Condition

The repair of offshore platform jackets is an important research direction in marine engineering, among which the grouting clamp reinforcement is the most widely used. In order to solve the hydrodynamic force of the grouting hoop under the joint action of wave and current in the complex sea condition, the Morison formula is used to analyze the linear wave load on the grouting hoop; then, based on the Morison formula, load force under the combined action of the wave and the ocean current on the clamps in different installation states was determined; finally, the screw jack and car jack were used to carry out the experiment of preventing the clamp from falling off. The mechanical grouting clamp experiment and the wedge tooth experiment were carried out at the same time. The innovative design of the mechanical grouting clamp, analyzed analogously through relevant experimental results and numerical analysis results confirmed that the reinforcement and repair method of the designed grouting clamp is of great help to the safety and reliability of the offshore platform jacket.

scholarly journals Robust Position Control of an Over-actuated Underwater Vehicle under Model Uncertainties and Ocean Current Effects Using Dynamic Sliding Mode Surface and Optimal Allocation Control

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 747
Author(s):  
Mai The Vu ◽  
Tat-Hien Le ◽  
Ha Le Nhu Ngoc Thanh ◽  
Tuan-Tu Huynh ◽  
Mien Van ◽  
...  
Keyword(s):  
Control System ◽  
Motion Control ◽  
Optimal Allocation ◽  
Position Control ◽  
Sliding Mode ◽  
Underwater Vehicle ◽  
Ocean Current ◽  
Model Uncertainties ◽  
Control Module ◽  
Dynamic Sliding Mode

Underwater vehicles (UVs) are subjected to various environmental disturbances due to ocean currents, propulsion systems, and un-modeled disturbances. In practice, it is very challenging to design a control system to maintain UVs stayed at the desired static position permanently under these conditions. Therefore, in this study, a nonlinear dynamics and robust positioning control of the over-actuated autonomous underwater vehicle (AUV) under the effects of ocean current and model uncertainties are presented. First, a motion equation of the over-actuated AUV under the effects of ocean current disturbances is established, and a trajectory generation of the over-actuated AUV heading angle is constructed based on the line of sight (LOS) algorithm. Second, a dynamic positioning (DP) control system based on motion control and an allocation control is proposed. For this, motion control of the over-actuated AUV based on the dynamic sliding mode control (DSMC) theory is adopted to improve the system robustness under the effects of the ocean current and model uncertainties. In addition, the stability of the system is proved based on Lyapunov criteria. Then, using the generalized forces generated from the motion control module, two different methods for optimal allocation control module: the least square (LS) method and quadratic programming (QP) method are developed to distribute a proper thrust to each thruster of the over-actuated AUV. Simulation studies are conducted to examine the effectiveness and robustness of the proposed DP controller. The results show that the proposed DP controller using the QP algorithm provides higher stability with smaller steady-state error and stronger robustness.

Modeling, simulation, and equilibrium analysis of tethered coaxial dual-rotor ocean current turbines

2021 ◽  
Vol 243 ◽  
pp. 113929
Author(s):  
Rodney Metoyer ◽  
Punnag Chatterjee ◽  
Kelsey Elfering ◽  
Matthew Bryant ◽  
Kenneth Granlund ◽  
...  
Keyword(s):  
Equilibrium Analysis ◽  
Ocean Current ◽  
Modeling Simulation

scholarly journals Numerical Study of an Oscillating-Wing Wingmill for Ocean Current Energy Harvesting: Fluid-Solid-Body Interaction with Feedback Control

2020 ◽  
Vol 9 (1) ◽  
pp. 23
Author(s):  
David Balam-Tamayo ◽  
Carlos Málaga ◽  
Bernardo Figueroa-Espinoza
Keyword(s):  
Energy Harvesting ◽  
Numerical Study ◽  
Angle Of Attack ◽  
Ocean Current ◽  
Control Synthesis ◽  
Dimensionless Number ◽  
Control Law ◽  
Loop Control ◽  
Power Extraction ◽  
Current Energy

The performance and flow around an oscillating foil device for current energy extraction (a wingmill) was studied through numerical simulations. OpenFOAM was used in order to study the two-dimensional (2D) flow around a wingmill. A closed loop control law was coded in order to follow a reference angle of attack. The objective of this control law is to modify the angle of attack in order to enhance the lift force (and increase power extraction). Dimensional analysis suggests a compromise between the generator (or damper) stiffness and actuator/control gains, so a parametric study was carried out while using a new dimensionless number, called B, which represents this compromise. It was found that there is a maximum on the efficiency curve in terms of the aforementioned dimensionless parameter. The lessons that are learned from this fluid-structure and feedback coupling are discussed; this interaction, combined with the feedback dynamics, may trigger dynamic stall, thus decreasing the performance. Moreover, if the control strategy is not carefully selected, then the energy spent on the actuator may affect efficiency considerably. This type of simulation could allow for the system identification, control synthesis, and optimization of energy harvesting devices in future studies.

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