Assessment of non-linear critical pressure of MWCNT reinforced hybrid sandwich semi-ellipsoidal dome under hydrostatic pressure: A numerical and experimental study

The present study involves the numerical and experimental buckling response of MWCNT reinforced composite sandwich semi-ellipsoidal dome subjected to uniform hydrostatic external pressure. The skin of the composite sandwich dome is made up of MWCNT-GFRP composite layers and the PLA honeycomb core, which is reinforced with and without strips. Various honeycomb core configurations, such as SRHC-1 to SRHC-3, are formulated in such a way that the strips are reinforced between the regular honeycomb core in longitudinal and transverse directions to enhance the stiffness characteristics of the structure. The nonlinear buckling analysis of the MWCNT reinforced composite sandwich dome is formulated and solved through the commercially available software ANSYS®. The geometry and material non-linearity of the MWCNT reinforced sandwich dome structures are incorporated in the numerical model while solving the non-linear differential equations and identifying the critical pressure of the sandwich structures using arc length method. The testings were performed to obtain the various mechanical properties, the non-linear behavior of yield stress with a plastic strain of the MWCNT-reinforced GFRP skin and the transverse shear modulus of the various honeycomb core patterns. The efficiency of the present numerical modeling and buckling analysis is confirmed by comparing the critical pressure obtained through the experimental buckling analysis performed on the MWCNT-reinforced prototype sandwich dome and the results available in the literature. Various parametric studies are performed on the MWCNT-reinforced composite sandwich dome to examine the influence of MWCNT reinforcement on the skin, honeycomb core patterns, stacking sequence of skins, aspect ratio and slenderness of the shells and geometric imperfections on the critical pressure.