Sandwich panels are a type of panel featuring a sandwich‑core structure, representing a specific class of composite material construction. As the name suggests, a sandwich panel is formed by stacking several distinct materials in a layered, “sandwich‑like” configuration, offering excellent strength, high stiffness, and relatively low weight. The sandwich‑core structure is a specialized form of composite construction, consisting of a lightweight yet moderately thick core material flanked on both sides by two thin, robust, and stiff face sheets. Sandwich‑core structures are characterized by their typically low weight, high stiffness, and superior strength.
　　Sandwich panels are a type of panel with a sandwich‑core structure and represent a specific class of composite material construction. A typical sandwich panel consists of five layers:
　　The top and bottom layers (known as the face sheets) are typically made of relatively rigid materials, designed to resist compressive and tensile stresses.
　　The intermediate layer, known as the core material, is typically composed of a low-density material with good shear strength and is used to prevent the face sheets from buckling inward or outward.
　　Between the face sheets and the core material, there are two adhesive layers that bond the core to the face sheets; these adhesive layers must be capable of withstanding shear and tensile stresses.
　　The working principle of sandwich panels is very similar to that of I‑beams. When a sandwich‑core structure is subjected to bending loads, the face sheets carry the primary in‑plane compressive and tensile stresses, while the core material—akin to the web of an I‑beam—resists the dominant shear stresses. As with I‑beams, increasing the distance between the two face sheets allows the sandwich panel to achieve a greater share of its stiffness from the core; moreover, because the core has a lower density, even thickening it has only a minor impact on the overall weight. Consequently, sandwich panels can maintain high stiffness while remaining lightweight.
　　Sandwich panels, owing to their excellent stiffness and strength combined with low weight and the relatively inexpensive materials used, play a positive role in cost control and reducing environmental impact, leading to their increasingly widespread application.

Honeycomb composite panels are constructed by laminating internationally popular structural foam and honeycomb core materials, offering excellent water resistance, outstanding thermal insulation, lightweight construction, and high strength. They are widely used in recreational vehicles, high-speed trains, ships, cold-chain logistics, modular cabins, outdoor camping, furniture, food processing, and other industries.