Study On Slamming Of V-type And I-type Corrugated Sandwich Panels

Hybrid sandwich structure with metal corrugated core is a new type of structure which can be applied to ships,marine structures,aerospace structures and vehicles.Compared with the traditional stiffened plate,honeycomb sandwich plate,three-dimensional lattice sandwich plate,PVC sandwich plate,FRP composite plate,GRP composite plate and other structural forms,the structure is quite different in many aspects such as production process,static and dynamic mechanical properties.This thesis attempts to apply the hybrid sandwich structure with V-type and I-type corrugated cores metal core to ship structural design.In this study,four types of corrugated sandwich plates were fabricated.The velocity,slamming pressure and acceleration were measured.Besides,three dimensional scanning and water jet cutting were used to study the failure of water contact panel and inner core,and the numerical simulation software LS-DYNA was employed to study the dynamic responses of the sandwich plates with V-type corrugated cores.The dynamic response and failure mechanism of the structure under water slamming impact are revealed.The main research works of this thesis are as follows:(1)In this thesis,three experimental models of hybrid sandwich plates with V-type corrugated cores are fabricated,and the dynamic responses of which under slamming load with different water entry velocity are studied experimentally.The experimental results show that the slamming pressure in the center is obviously higher than that near the boundary.There is a negative correlation between the slamming velocity and the duration of slamming pressure.And the peak value of slamming pressure is proportional to the exponential power of water entry velocity.The main failure modes are the overall deformation of the facesheet and the serious wrinkle of the corrugated core.Filling the low density polyurethane foam increases the slamming pressure peak of the structure.Though filling the low density polyurethane foam has little effect on the duration of slamming pressure,it reduces the acceleration amplitude of the structural panel.(2)The dynamic responses of hybrid sandwich plates with V-type corrugated cores under slamming load were investigated numerically by using the finite element software LS-DYNA.The effects of two kinds of density 31kg/m3 and 50kg/m3 polyurethane foam filling on the slamming resistance of structures were discussed.Numerical simulation results are compared with the experimental results,which are in good agreement.The results show that the polyurethane foam filling inside the core can provide support for the core webs,thereby preventing the web from plastic buckling.Low density polyurethane fillers do not necessarily reduce the maximum plastic deformation.(3)In this thesis,two experimental models of hybrid sandwich plates with I-type corrugated cores are fabricated,and the dynamic responses of which under slamming load with different water entry velocity are studied experimentally.The experimental results show that the slamming pressure in the center of I-type sandwich structure is obviously higher than that near the boundary.Filling the low density polyurethane foam increases the slamming pressure peak of the structure,while reduces the acceleration amplitude of the structural panel.For the I-type corrugated hybrid sandwich panel with polyurethane foam filler,the failure modes are mainly the overall deformation of the facesheet and the local compression deformation of the corrugated core,and the filler material on the boundary is sheared and cracks appear.With the same facesheet and core size,the slamming pressure of I-type corrugated sandwich structure were lower than those of V-type corrugated sandwich structure,however the acceleration amplitude was higher.The research work of this thesis provides a useful reference for the engineering application of hybrid sandwich structure with metal corrugated core in the field of ship and ocean engineering.