Research On Optimization Design Of Pressure Hull Of Water-jet Long Distance Underwater Glider

The underwater glider is a new type of ocean observation platform driven by buoyancy.It has the advantages of real-time,remote controllable,long endurance and low cost.In the underwater glider,the mass of the pressure hull accounts for more than 30% of the total mass,and the drainage volume accounts for more than 90% of the total drainage volume,which is an important part of the underwater glider.On the one hand,in the process of dive in a typical underwater glider,as the depth increases,the buoyancy increase of the glider due to the increase in seawater density will be slightly greater than the change in the buoyancy of the glider caused by the deformation of the sea pressure and temperature.Therefore,the glider buoyancy regulating device is required to actively perform buoyancy control to achieve the purpose of glider dive,which will inevitably increase the power consumption of the glider actuator.On the other hand,the heavier pressure hull limits the battery capacity of the underwater glider.In view of the above two aspects,under the condition that the strength and stability of the pressure hull meet the requirements,the battery capacity can be increased by optimizing the structural parameters of the pressure hull,reducing the quality of the pressure hull and increasing the deformation of the pressure hull.Space and reducing the power consumption of the buoyancy regulating device are of great significance for improving the endurance of the underwater glider.The main research contents of this paper are as follows:(1)The buoyancy changes and energy consumption of the underwater glider during the gliding process are analyzed.The optimization of the pressure hull is closely related to the improvement of the voyage,and the expression of the single-section energy increase of the objective function is obtained.(2)Based on structural mechanics and material mechanics,the stress of the pressure hull is equivalent to the stress of the foundation beam,and the circumferential stress of the hull at the midpoint of the rib,the axial stress of the hull at the rib or end cap,the stress of the rib,and the hull are derived.The critical pressure of plate instability,the critical pressure of rib instability and the calculation formula of the total instability critical pressure are obtained,and the constraint function which is accurately applied when the pressure hull is optimized is obtained.The formula for calculating the compressive deformation of the pressure hull is derived.The relationship between the structural parameters and the strength,stability and compressive deformation of the pressure hull was studied,which provided a basis for the optimization of the pressure hull.(3)With the goal of increasing the energy of single section and satisfying the requirements of strength and stability,the genetic algorithm,simulated annealing algorithm and genetic annealing evolution algorithm are used to optimize the pressure hull of the waterjet propulsion long-range underwater glider.The annealing evolution algorithm has the best optimization effect.The optimization results show that the quality is reduced by 7.46% and the battery carrying capacity is increased by 11.23% before the optimization;the deformation of the hull is increased by 14.93% at 1000 m water depth,the energy consumption of buoyancy is reduced by 13.99%,and the energy of single section is 6512.2J.It can increase the endurance by 19.47%.