A “Sandwich Structure” is a biomimetic composite structure that mimics the principles of lightweight, high-strength natural structures like leaves, bones, and feathers. It consists of three parts: two thin, rigid, high-strength face sheets (skins) and a thick, lightweight core material in between, all bonded together firmly with high-performance adhesive into an integrated whole.
In this structure, PP Honeycomb plays the role of the “core material,” and its function is crucial:
- Transfers Shear Forces and Maintains Spacing: The core separates and firmly supports the top and bottom face sheets. When the sandwich panel bends, the top skin is compressed, the bottom skin is tensioned, and the core primarily withstands the shear stress that connects them and prevents them from sliding past each other. This is analogous to the web of an I-beam connecting the flanges.
- Provides Stiffness and Enables Lightweighting: The bending stiffness of a structure is proportional to the square of the distance between the face sheets. The thicker the core (greater skin spacing), the greater the panel’s stiffness increases geometrically, with minimal weight addition. PP honeycomb core, with its extremely low density and efficient structure, perfectly achieves the goal of “using air to add thickness and stiffness.”
- Transfers and Distributes Loads: When subjected to local impact or pressure, the core rapidly disperses the load over a larger area of the face sheets, preventing stress concentration.
- Provides Additional Functions: The static air within the cells provides thermal and acoustic insulation; the PP material offers corrosion resistance and damping properties.
Thus, PP Honeycomb is the soul of the sandwich structure, endowing it with exceptional “specific stiffness” and “specific strength.” Without a quality core, the sandwich panel loses its core value.
