Design Study On Ceramic Pressure-resistant Shell Of 10,000-meter Underwater Glider

In recent years,with continuous breakthroughs in tackling the technical bottleneck of abyss detection,abyss science is becoming a latest frontier field with huge potential in international earth sciences,especially marine science.Various types of submersibles have also become effective tools for understanding the abyss.The underwater glider achieves heave motion through adjustment of the oil bag,and thus has many advantages,including low cost,strong endurance,wide observation range,and the loading capability for a variety of sensors,which makes it promising to become an ideal platform for scientific observation of the abyss.However,the ultra-high pressure of the abyss of the sea also brings new technical challenges to the pressure-resistant shell of the 10,000-meter underwater glider.To this end,this article has conducted a research on the design of pressure-resistant shell of a 10,000-meter underwater glider,and the main contents and results are as follows:To improve design of the pressure-resistant shell structure of the 10,000-meter underwater glider developed by this research group,the uneven radial deformation of the existing ceramic cylindrical shell is analyzed through theoretical calculation and finite element simulation,and then the design scheme of ceramic cylindrical shell with equal radial deformation is proposed.Improvement measures are proposed to solve the excessive tensile stress on the end face of the cylindrical shell,which is caused by the Poisson effect of the bonding structure at both ends of the ceramic cylindrical shell.By integrating the design plan of the ceramic cylindrical shell with equal radial deformation,the ceramic cylindrical shell is improved and designed according to the stability theory of the long cylindrical shell;weight of the connecting rib ring is designed to be reduced while ensuring the strength and stability;the finite element simulation is utilized to analyze and verify the sealing performance of the improved structure;on the basis of the stability theory of external pressure spherical shell and the thick spherical shell theory,the weight of hemispherical end cover of the pressure shell is also designed to be reduced.Finite element simulation analysis is used to verify the stability of the improved ceramic cylindrical shell under the abyssal ultra-high pressure;the two different radial deformations of the cylindrical shell compartments are compared with each other,and the improved cylindrical compartment basically realizes equal radial deformation.According to the plan proposed to improve the bonding structure,the tensile stress on the end face of the improved ceramic cylindrical shell is significantly reduced.Considering the density change of the seawater and the compression of the pressure shell in the 10,000-meter profile,the net buoyancy change of the pressure-resistant shell before and after the improvement is analyzed.The increase in the thickness of the ceramic cylindrical shell causes the overall increase of the pressure shell weight,making the net buoyancy of the pressure shell slightly smaller after the improvement.The proposed design significantly improves the stress conditions of the ceramic cylindrical shell,enabling the ceramic cylindrical shell to realize quasi-uniform deformation under external pressure,while reducing the tensile stress on the end face of the ceramic cylindrical shell,which can effectively extend the service life of the pressure-resistant shell.