Mechanical Characteristic Analysis Of Typical Metallic Sandwich Wedge Panels Under Water-Entry Slamming

Lightweight Metallic Sandwich Structures have excellent advantages, such asanti-shock, anti-ballistic impact, noise, heat insulation etc. They have attracted more andmore extensive attention in the field of ship and marine engineering applications, however,the literatures about mechanical characteristic of such sandwich structures underslamming loads is rarely reported. The slamming loads and response of the two kinds ofselected sandwich panels with I and V core under the water-entry slamming loads arestudied by using the numerical simulation method in this thesis.Firstly, the key techniques of water-entry slamming problems of complex structuresare studied by using FEM. The optimal selection method of the mesh density and couplingstiffness which are needed to focus on in simulation calculation are determinded. Theresponse of two-dimensional wedges under water-entry slamming is studied to show theeffect of the elasticity of structures on the slamming pressure. In addition, the test ofwedge water-entry existing in literature is simulated by using the FE softwareANSYS/LS-DYNA, the numerical results are compared with the experimental results tocomfirm the simulation method.After that, the the water-entry slamming problems of metallic sandwich wedge panelswith I and V core are studied by using the direct numerical simulation method, and someuseful conclusions are obtained:(a) The curves of slamming pressure attribution by thethree kinds of panels with equal mass, I core sandwich，V core sandwich，stiffness panel,are different from each other, but the slamming forces are all the same.(b) Both of thedeformation responses of I core sandwich panels and V core sandwich panels are less thanthat of the stiffness panels, the bottom panels of sandwiches appear local depressiondeformation.(c) The peak pressures of slamming at the mid of the bottom pannels nearlyare proportionate to the square of the velocity, the deformation of the panels increases asthe velocity increases.(d) The slamming pressure and the response of sandwich panels areaffected differently by the parameter of metallic sandwich, such as the sheet thickness, thecore thickness and the core height.Finally, the deformation and failure of metallic sandwich wedge panels subjected the slamming impact are studied, two kinds of failure modes are conducted: one mode isplastic deformation and failure on the bottom face sheet, the other one is bucklingdeformation and failure on the core sheet. The effects of sheet thickness and core thicknesson the failure modes are studied to provide as a reference for the follow-up experimentalresearch and sandwich design for anti-slamming impact.