Motion Response Analysis And Mooring System Research Of Sea Launch Vessel

Maritime launch has many natural advantages compared to land-based launch,but it also poses corresponding difficulties due to its special launch environment.For example,launching at sea faces complex sea conditions such as high winds and waves,which puts higher requirements on the stability of offshore launch ships(platforms).Therefore,this article takes the process of offshore thermal launch as the research object.Firstly,it simulates the impact of the carrier rocket on the offshore launch ship during the launch process.Based on this,it explores the impact of the wind wave direction,launch eccentricity distance,and launch timing on the motion response and mooring system of the offshore launch ship during the rocket launch phase under the disturbance of wind,waves,and currents,Finally,optimize and analyze the layout of the mooring system under rocket launch conditions.The research content of this article specifically includes the following content:(1)Simulated calculation of rocket impact load: The impact process of the nozzle wake of a certain type of rocket was simulated,and the time history results of the impact load on the offshore launch vessel during rocket launch operations were obtained.The impact of the Laval nozzle on the launch vessel was simulated and calculated.The user defined(UDF)method was used to control the dynamic grid area,and the differences in impact of different sizes of launch vehicles on the launch vessel deck were analyzed.For the launch vehicle nozzle,the greater the inlet pressure,the greater the impact load on the bottom deck.Under the condition of a pressure inlet of 13 Mpa,The maximum weighted average pressure of the bottom deck area reached0.399 Mpa.(2)Simulate and analyze the motion response and mooring rope stress of offshore launch ships using the general hydrodynamic software AQWA,with a focus on verifying and analyzing the research and development plan project indicators involved in this article(i.e.the roll motion amplitude of offshore launch ships should not exceed 3 °).The main contents are as follows:First,the AQWA fluid mechanics diffraction module is used to analyze the frequency domain of the offshore launch ship,and the hydrodynamic characteristics of the offshore launch ship are obtained,which lays the foundation for the time domain coupling analysis of subsequent offshore launch operations;Secondly,the hydrodynamic response module of AQWA is used to build a time-domain response model of the offshore launch ship,and the analysis results of the motion response of the offshore launch ship in six degrees of freedom directions and the stress state of the mooring rope at different wave angles,rocket launch eccentricity distances,and launch times are obtained.After simulation analysis,it is necessary to avoid launching operations of the offshore launch ship in transverse waves.In addition,If a suitable launch time is found,the ship’s motion caused by the impact load of the rocket launched at sea will be offset and compensated by the effects of wind,waves,and currents.(3)Based on the results of time-domain coupling analysis of offshore launch vessels,by exploring the mooring arrangement methods such as mooring rope length and mooring point position,while ensuring the safety of offshore launch vessels,it is possible to appropriately increase the length of mooring ropes and place mooring points below the waterline to improve the overall stability of offshore launch vessels,and also provide reference for the design of mooring systems for offshore launch vessels.