Research On Molding Method And Bending Performance Of Plastic Honeycomb Sandwich Structure

With the progress of aerospace technology, honeycomb sandwich structure has a rapid development. Honeycomb sandwich panel is a high-performance structure material. The structure has excellent performance in stiffness, strength, fatigue strength, thermal insulation, sound insulation, seismic weight and so on. So the structure has been widely used in buildings, aircraft, automobiles, ships and other aspects. The aim of this paper was to study the forming method and bending performance of plastic honeycomb sandwich structure. Plastic honeycomb sandwich panel was prepared by extrusion and molding methods, using plastic Honeycomb sandwich panel production line. The bending performance of honeycomb sandwich panel was studied by tested and Workbench finite element analysis methods. The influences of size parameters, including the cell wall thickness, cellular inner edge, core layer height, and skin thickness of the honeycomb panel on the equivalent modulus and specific modulus were studied. The transverse and longitudinal bending performances with different size of the honeycomb were compared. By changing the angle of hexagon, introducing conception of functionally graded materials, and designing gradient wall thickness, the influence of the honeycomb core in the longitudinal and transverse elastic modulus with different angle and graded wall thickness were investigated. Finally, the optimal design of the plastic honeycomb sandwich structure was carried out by the multi objective optimization method of surrogate model.Studies showed that the longitudinal bending elastic modulus of hexagonal honeycomb panel was higher than the transverse elastic modulus, and the differences increased with the ratio of cellular wall thickness and length increased; The increase of cell wall thickness caused the modulus increased and the equivalent modulus decreased. With the increase of the thickness of the skin, the equivalent elastic modulus of the hexagonal honeycomb panel increased, and the specific modulus increased first and then decreased; With the increase of inner edge length, the equivalent elastic modulus decreased, and the specific modulus increased first and then decreased; The increase of the core layer height of honeycomb panel caused a significant increase in flexural rigidity EI, while the effect of specific modulus first increased and then decreased, and the specific modulus achieved maximum when the core layer height was 5 mm. Elastic modulus of honeycomb core was sensitive to the changes of the angle of hexagon. With the increase of the angle, the transverse elastic modulus decreased rapidly, while the longitudinal elastic modulus increased, and the elastic modulus of the honeycomb core had a great change. When θ=30°, the anisotropic difference was less; When θ=30°, the transverse elastic modulus was stronger than that of the longitudinal direction. When θ=45°, the longitudinal elastic modulus was stronger than that of the transverse direction. The gradient wall thickness had some influence on the in-plane elastic modulus. The appropriate gradient changes had a reinforcing effect on the in-plane elastic modulus. On the contrary, there was a weakening effect. The multi-objective optimization method based on surrogate model could successfully find the four optimal parameters of the honeycomb sandwich structure, which achieved the goal of high stiffness and light weight, greatly improving the optimization efficiency. Based on the multi-objective intelligent optimization analysis, the optimal solution of the honeycomb sandwich panel made elastic modulus increased by 19.9%, while the relative density only increased by 2.1%.