The composite foam sandwich panel structure is a structural form of advanced composite materials at present, with many advantages: lightweight, high strength, good stability, corrosion resistance, heat insulation and sound insulation, etc., so the composite sandwich panel structure can also be used. It is used in the manufacture of some maintenance wall panels, roof panels and partition panels. At present, the movable wall panels on the market are mainly composite panels of various sandwich structures, which have the important performance of thermal insulation and supporting the house structure.

    There are many types of composite sandwich panels. According to the form and type of core materials used in the sandwich panel structure, the sandwich panel structure can be divided into the following types: honeycomb sandwich panel structure, lattice sandwich panel structure and foam sandwich panel structure.

    The sandwich panel structure with fiber-reinforced composite material as the panel and high-strength foam as the sandwich material has been widely used. The fiber-reinforced composite material mainly includes glass fiber reinforced composite material and carbon fiber reinforced composite material, but its cost is considered comprehensively. , Glass fiber reinforced composite materials (GFRP) are widely used: in addition, the foam core is generally divided into PMI foam, PVC foam and so on.

    Factors such as heat, chemical shrinkage, and collision during transportation of the core material and the panel may cause damage to the interior of the foam sandwich composite. At this time, the degumming and delamination damage at the surface-core interface is the most common damage, that is, the sandwich panel. interlayer cracking. Interfacial interlayer cracking and debonding not only affect the transfer of stress between the core and the panel. Moreover, when the structure is loaded by external force, crack propagation will occur in the debonded area, and eventually the entire structure will fail. therefore. One of the main failure modes of foam sandwich composite structures is the interlaminar cracking of the core and the panels.