Study On Dynamic Coupling Behavior Control Mechanism Of Multiple Floating Bodies Based On Integrated Transport Of Offshore Wind Turbines

The air-floating bucket foundation and integrated transportation installation technology are able to realize the "green,environmental protection,efficient,low-cost and large-scale" development of offshore wind power,which is of great significance to the development trend of parity of China’s offshore wind power industry.The integrated transportation technology of the air-floating bucket foundation is one of the core technologies of its integrated transportation and installation technology.Different from the traditional solid-floating structure,the air buoy foundation,as an air-floating structure,forms a coupled structure system of solid-air floating with the one-step transportation and installation vessel in the process of transport.The transportation scheme will lead to a great difference in the floating behavior of the structural system.In the process of transport,in addition to researching the influence of environmental loads on the floating behavior of structural system,the interaction between the air cushion structure and the coupled structural system should also be studied in consideration of the floating characteristics of bucket foundation,so as to provide theoretical support and guidance for the integrated transportation of air-floating bucket foundation.In this paper,the bucket foundation integrated structure system is taken as the research object.The coupling dynamic characteristics and floating behavior control mechanism in the process of sea towing are studied.The specific research contents are as follows:Firstly,based on the micro-wave hypothesis,the diffraction and radiation problems of large diameter air buoy foundation are solved by potential flow theory,and the analytical solutions of foundation diffraction force,additional mass coefficient and damping coefficient are obtained.The relationship between the additional mass coefficient and the damping coefficient and the incident wave frequency is further studied.By solving the gas elastic stiffness of thin-wall air-floating structure,the formulas for calculating the stiffness and restoring force of heaving and swaying motions of foundation are obtained.Then the 6-DOF motion equation of air-floating is established.The free swing motion and the swing motion of the foundation in regular waves are solved.The variation law and mechanism of gas-liquid coupling motion of the air cushion structure are clarified.Secondly,through 1:10 large-scale field model test,the influence of the air cushion structure on the movement characteristics of the structural system,the air floatation stability of the bucket foundation and the interaction between the bucket foundation and the vessel were studied,revealing the action mechanism of air cushion structure on airsolid floating multi-body coupling structure system.According to the results of the study,the structure system of "foundation carry the vessel" is proposed.Through the close together union of bucket foundation and the vessel,this structure form improve the structure of sports performance and the floating stability of the bucket foundation.The interaction force is transformed into structural internal force,which reduces the risk of structural damage caused by impact load caused by collision between bucket foundation and the vessel.Thirdly,aiming at the problems of dynamic response characteristics and floating transport behavior control method of the " foundation carry the vessel " air-cap principle structural system,the air-solid floating coupled numerical model was established and verified.The sensitivity of dynamic response characteristics of the structural system under the action of environmental factors was studied.The evolution process of floating transport behavior of structural system under the combined action of wind and waves was further studied,and a quantifiable control method of floating transport behavior of air buoy foundation was proposed.Finally,based on the bucket foundation construction project,the construction monitoring of the transportation process of the bucket foundation is carried out.The floating behavior of bucket foundation in integrated towing transportation is monitored,including: change rules of motion response of “foundation carry the vessel” air-cap principle structural system,air pressure and buoy liquid level under different environmental loads.At the same time,the control method of floating transport behavior of structure system is verified and improved by using the engineering measurement results.