The adhesive connection method is a method in which a panel and a core are heated and pressurized in a continuous forming machine with a thermosetting adhesive and then compounded. With this method of connection, the honeycomb panel does not withstand external heating cycles, but surface pretreatment is required before connection. In addition, the strength, service life, and allowed working environment of the adhesive honeycomb panel are largely affected by the performance of the adhesive. For example, due to high altitude radiation and low temperature, the organic adhesive in the honeycomb sandwich structure used in the aerospace field is prone to molecular chain breaks and cold embrittlement, which reduces the straight tensile strength of the honeycomb panel by about 50%. Therefore, this method is rarely used today with increasingly high requirements for cellular performance.
Welding method is divided into brazing, seam welding, laser welding and instant liquid phase connection. Because the seam welding process is more complex, and because the welding wheel stays at each welding point for a short time during the seam welding process, the heat dissipation conditions on the surface of the weldment are poor, and it is easy to overheat, which affects the overall mechanical properties of the honeycomb panel prepared. And the transient liquid phase diffusion connection is mostly used in multi-alloy systems; laser welding equipment has a large investment cost, so it is currently widely used by brazing. The assembly and clamping method of the honeycomb panel before brazing is to first assemble the honeycomb core with an assembly fixture one by one, then clamp the honeycomb core to the upper and lower panels, and then use a five-point clamping method to clamp the entire metal honeycomb panel with a flat thin steel plate.
In general, whether it is the connection of the honeycomb core or the connection between the honeycomb core and the panel, welding them together can form a strong metallurgical bond between the joints. Its overall mechanical properties are superior to the honeycomb sandwich panels prepared by cementing. Many, so in order to obtain high-performance metal honeycomb sandwich panels, brazing has broad development prospects.
