Study On Interface Fracture Behavior Of Aluminum Honeycomb Sandwich Structure

Sandwich structure is consisted of high strength panel and intermediate low-density core,and the commonly used core is honeycomb structure.During the load-bearing process,the panels are typically subjected to in-plane tensile,compressive and shear loads,while the core layer is used to resist transverse shear loads and maintain transverse stability.The strength and stiffness of the structure are largely influenced by the material,but the quality of the bond between the panel and the core layer also has an important impact on the safety and reliability of the sandwich structure.The debonding failure of the bonding interface between the panel and the core can significantly reduce the mechanical properties of the sandwich structure during loading,and further lead to structural damage.Therefore,it is necessary to consider the interface failure behavior to obtain the best performance in the design of the honeycomb sandwich structure.In this paper,the fracture behavior of the bonding interface between skin and honeycomb core was studied by numerical analysis and experimental verification,taking the interface of light Aluminums alloy honeycomb sandwich structure as the research object.Firstly,according to the characteristics of the bonding interface of the aluminum alloy honeycomb sandwich panel,the double cantilever beam test and the three-point bending test of the skin/skin,skin/honeycomb core interface were respectively carried out to obtain the fracture parameters of skin/skin,skin/ honeycomb core interface.At the same time,a single-lap experiment was performed to obtain the shear strength of the skin/skin,skin/honeycomb core interface as the initial parameters of the bilinear cohesive zone model.Secondly,numerical verification of interface fracture behavior based on bilinear cohesive zone model is carried out.Based on the mode I fracture experiment,the finite element software ABAQU was used to verify the experimental results of the double cantilever beam of solid and honeycomb sandwich structures.Based on the bilinear cohesive zone model,the mechanical response of aluminum honeycomb sandwich structure in in-plane load is analyzed.The effect of interface debonding on the bearing capacity of sandwich structure is studied by the combination of experiment and numerical method.Finally,the failure modes and mechanical properties of honeycomb sandwich structures with complex interfaces are discussed.The finite element model of honeycomb sandwich structure with embedded parts in out-of-plane axial tension load is established by numerical analysis method,while the axial tension test of honeycomb sandwich structure with embedded parts was carried out.And then predicted the influence of interface behavior on the bearing capacity of such structure.The above research realized the calculation of the bearing capacity of the honeycomb sandwich structure considering the interface fracture behavior.The fracture parameters of the bilinear cohesive zone model are obtained by the combination of experiment and numerical simulation,and the bilinear cohesive zone model is verified by numerical analysis.The experimental results are consistent with finite element method,which provides data support for the design of the bonded interface of aluminum alloy honeycomb sandwich structure,and provides reference for the improvement of structural bearing capacity.