Research On Mechanical Properties Of Honeycomb Plate Used In Metallic Thermal Protection System

Metal thermal protection system(MTPS), which is composed of three parts: metal honeycomb panel, thermal insulation material and stents, is an important structure to protect the high-speed aircraft from overheating. The honeycomb panel is composed of two face sheets and a honeycomb core, and it has been widely used in aviation and aerospace area for its excellent heat-shielding performance, light weight, high specific strength and stiffness. As the main surface load-bearing structure, the metal honeycomb panel would be affected by variety of loading force. Moreover, the debonding defect between panels and honeycomb core during the manufacture and application process is one of the common and most serious defects. So, it's significant to study the mechanical properties of metal honeycomb panel with typical defects.Based on brazing metal honeycomb panel as the test sample, we studied the pressing and three point bending mechanical properties of the honeycomb panel. Firstly, through the process of gear rolling, sizing, spot welding, grinding and vacuum brazing, the titanium and high temperature alloy honeycomb panel were made. Secondly, according to different working environment, pressing test of titanium alloy honeycomb panel and three point bending test of high temperature alloy honeycomb panel were carried separately to study the influence on mechanical performance of honeycomb panel caused by high temperature and defects. Finally, by ANSYS/LS-DYNA, we studied the mechanical properties of honeycomb panel by finite element simulation, put forward a new method of spotweld honeycomb modeling, got the stress distribution in test process and studied the influence of structure and process parameters on mechanical properties of honeycomb panel.The study shows that the high temperature condition has a great influence on the bearing capacity of honeycomb panel. Compared with room temperature,when the temperature is 200? and 400?, the honeycomb panel pressure load is reduced by 17.5% and 35.4% respectively. The pressure load grows with the increase of tensile and shear failure strength of weldspot and the tensile failure strength owns greater influence on pressure load of the honeycomb core than shear strength. During the three point bending test, reverse bulge appears in the defects compression area and extends to complete damage along width direction with the increase of defect area. When the defect is located in the extruded area, the honeycomb panels will have higher bending capability and the ultimate bending load of rectangular defects sample is higher than that of circular defect sample.