Numerical Analysis And Experimental Verification On Buckling Of Multiple Intersecting Spherical Pressure Hull

As the key component of deep sea exploration equipment manned submersible,the design of pressure hull is particularly important.The existing deep-sea pressure hull is the single spherical pressure hull,but the single spherical pressure hull has the disadvantages of low space utilization,unfavorable to the interior equipment layout and poor hydrodynamic performance;while multiple intersecting spherical pressure hull is the extension structure of single spherical pressure hull,which has the advantages of both the spherical and cylindrical pressure hull,not only the buoyancy coefficient is low,but also the space is large and it is easy to arrange the equipment inside the cabin.Therefore,it is of great significance to carry out the numerical analysis and experimental verification on buckling of multiple intersecting spherical pressure hull,and to improve the overall stability of the multiple intersecting pressure structure and the exploration and development of the large space submersible.The main contents and conclusions of this thesis are as follows:(1)Based on the main geometric parameters of multiple intersecting spherical pressure hull,numerical model was established to study the influence of geometric parameters of multiple intersecting spherical pressure hull on its structural characteristics.The results showed that the analytical model can be simplified to the typical double or three spherical pressure hull.In order to avoid the two typical failure modes of multiple intersecting spherical pressure hull,the deformation displacement of multiple intersecting spherical pressure hull was consistent with the deformation and displacement of the whole spherical pressure hull after the opening of multiple intersecting spherical pressure hull;based on the theory of deformation coordination design,the typical three spherical pressure hull was designed.(2)The typical three spherical pressure hull structure was used as the study object,the stability analysis was carried out.The results showed that the linear buckling of the three spherical pressure hull had nearly the same adjacent buckling load values;and for the three spherical pressure hull,the nonlinear buckling load of the multiorder linear buckling mode superposition was far less than the critical buckling load under the single order buckling mode defect.A single spherical pressure hull numerical model with the same size parameters was established,and the comparative analysis of the stability of multiple intersecting spherical and single spherical pressure hull was carried out.The results showed that the buckling behavior of the three spherical pressure hull was highly correlated with the single spherical pressure hull,and the ultimate instability load of multiple intersecting spherical pressure hull can be predicted by the theoretical calculation and numerical analysis of single pressure hull.In the same way,based on the equal volume and equal thickness design conditions,the design of ribless and ribbed cylindrical pressure hull was carried out,and the numerical model of cylindrical pressure hull with corresponding dimensions was established,and the stability of multiple intersecting spherical and cylindrical pressure hull was compared and analyzed.The results showed that loading load of the three spherical pressure hull was obviously better than that of cylindrical pressure hull.(3)The typical double spherical pressure hull structure was selected and the deformation coordination theory was applied to determine the design parameters of the proportional model.The scale model of stainless steel was made by stamping forming technology.The real shell model was obtained according to the three dimensional scanning and non-destructive thickness test,and the comparison between the experiment and the numerical analysis was carried out.The results showed that the numerical analysis was in good agreement with the test results.The width of the ring ribs and the thickness of the ring ribs had a significant effect on the buckling load of the double spherical pressure hull.With the increase of the thickness of the ring ribs,the plastic stress of the double spherical pressure hull was distributed from the stiffened ribs to the regions far away from the stiffened ring ribs.The ultimate failure mode of multiple intersecting spherical pressure hull was consistent with that of single spherical pressure hull.The stability analysis of multiple intersecting spherical pressure hull can be simplified to single spherical pressure hull.(4)The parameters of the three spherical and cylindrical pressure hull were designed successively,and the resin test model was built based on the technology of material addition.The real three spherical and cylindrical pressure hull model was obtained based on three dimensional scanning experiments,then the comparison and analysis of the test and the numerical analysis were carried out.The results showed that the test results were in good agreement with the numerical analysis results.The loading load of the three spherical pressure hull was obviously better than that of cylindrical pressure hull,and the loading load was about 4 times that of the stiffened cylindrical shell,which proved that multiple intersecting spherical pressure hull had good pressure resistance.