The core materials for composite sandwich structures are: rigid foam, PMI foam, honeycomb and balsa wood. Rigid foams mainly include polyvinyl chloride (PVC), polyurethane (PU), polyetherimide (PEI) and acrylonitrile-styrene (SAN or AS), polymethacrylimide (PMI), and foaming. Polyester (PET), etc. The honeycomb core material is glass cloth honeycomb, NOMEX honeycomb, cotton honeycomb, aluminum honeycomb, and the like. The honeycomb sandwich structure has high strength and good rigidity, but the honeycomb has an open-cell structure, and the bonding area with the upper and lower panels is small, and the bonding effect is generally not good. The balsa core material is a natural product. The common balsa cores are mainly produced in South American plantations. Due to the climatic reasons, balsa wood grows especially fast in the local area, so it is much lighter than ordinary wood and its fiber. With good strength and toughness, it is especially suitable for composite sandwich structures. Sandwich materials are used in a wide range of applications, including energy, aerospace, marine, transportation, and construction. The sandwich material is one of the key materials of wind power blades. In order to increase the structural rigidity, prevent local instability, and improve the load resistance of the whole blade, sandwich structures are generally used in the leading edge, trailing edge and shear rib of the blade. . The core materials for wind turbine blades are mainly PMI foam, Balsa balsa and PET foam. A typical design is to use a higher strength Balsa balsa (density 150 kg/m3) for the load-bearing part near the root, and cross-linked PVC foam (density 60 kg/m3) for carrying The smaller the tip near the tip, the thickness of the sandwich material gradually decreases from the root to the tip. There are also leaf manufacturers that only use Balsa balsa or foam.