| The pressure shell of deep submersible plays an important role in resisting the deep water pressure and protecting the safety of personnel and equipment inside the submersible.In this paper,considering the excellent characteristics of biological eggshell,a kind of egg-shaped pressure-resistant shell was studied,and the existing egg-shaped mathematical model was adopted to establish the egg-shaped pressure-resistant shell model.The main contents and conclusions are as follows:(1)The mathematical model of the egg-shaped pressure-resistant shell is analyzed,the curve diagram and equation of the egg-shaped shell are given,the calculation methods of the first curvature radius,the second curvature radius,the coefficient of the egg-shaped shell and the volume formula are derived,and the solution formula of the linear elasticity theory of the egg-shaped pressure-resistant shell is given.In combination with the design factors of the pressure shell and the failure of the stability of the pressure shell,the performance of the eggshaped pressure shell is better than that of the conventional shell of the same volume,which verifies the feasibility of the design of the egg-shaped pressure shell.(2)Egg-shaped pressure-tight shell of metal material(isotropic material)eigenvalue buckling analysis,with reference to the volume of a spherical shell is commonly used(diameter of 2 m),metal shell model is established,under the different shell thickness,egg-shaped pressure-tight shell buckling critical load of the simulated values within 15%,the difference between the theoretical solution is buckling occurred in egg-shaped pressure shell of the waist,the theoretical value is larger.The results show that the reinforcement can effectively improve the stability of the shell.Compared with the longitudinal reinforcement,the cyclic reinforcement has more significant effect on the stability of the shell,and the grid reinforcement has the best effect on the stability of the shell.The effect of shell thickness on the stability of egg-shaped pressure-resistant shell is analyzed by orthogonal test.The second one is the stiffening method.The ring-stiffening method has a greater effect than the longitudinal one,but the overall effect is better than the thickness of the stiffening body.The worst effect on stability is the thickness of the reinforcement.(3)The nonlinear buckling of composite eggshell with damage was analyzed.The simulation method of dynamic explicit combined with Hashin damage failure criterion was proposed,and the shell buckling performance under different egg-shaped coefficients was analyzed.The results showed that the egg-shaped structure could not be too long and thin,nor too short and fat.By considering the comparison of material damage or not,the displacement load curve of shell with material damage after buckling is lower,and the buckling state is also different,but the critical buckling load has little difference.By analyzing the influence of distribution mode of composite materials on shell stability,the x-type distribution of gpl-epo and fib-gpl-epo materials is better than the o-type distribution,better than the a-type distribution and better than the v-type distribution.Different carbon fiber lamination directions also have an impact.The [0/90]10S carbon fiber lamination mode has the best buckling performance,followed by [90/0]10S carbon fiber lamination mode,and [45/45]10S carbon fiber lamination mode has the worst buckling performance.Head to shell opening hole at the bottom of the(single),head(double holes),stability and hole radius on the shell was analyzed,and the hole will reduce the stability,the larger the radius decrease,the more open hole radius of 200 mm,puckering reduced 9.34%,double holes decrease by 14.47%,and by reducing,egg-shaped coefficient of 0.7,double holes of flexion position from the bottom of the shell is transferred to the waist. |
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