Composite Panels Information
Composite panels are sandwich structures that consist of multiple layers bonded together to create multilayer sheets, cored laminates, or industrial structural panels. They are made from a variety of metal, plastic, wood, ceramic, glass, and fiber-based composite materials.
Panels and panel materials carry product specifications such as:
- compressive strength
- tensile strength
- shear strength
- shear modulus
- flexural strength
- flexural modulus
- water absorption
Panels and panel materials are available from a variety of sources and meet standards from organizations such as the American Society for Testing Materials (ASTM). Some panels and panel materials are made of plywood, a manufactured wood product that resists bending, cracking, shrinkage, and warping. An engineered wood, plywood is made of sheets of veneer that are pressed and glued together with the grains arranged in opposite directions. Typically, plywood panels are made of softwoods such as birch, fir, mahogany, pine, or spruce.
Southern pine panels are used in exterior siding applications. Birch and mahogany are used to produce an extremely lightweight but durable product called aircraft plywood. Plywood structural panels that are designed for interior building and construction applications are made with quick-drying but relatively inexpensive urea-formaldehyde glue. By contrast, wooden panels and panel materials that are designed for the outdoors use more expensive but more durable water-resistant glues.
Oriented strand board (OSB) panels and panel materials are multi-layer products made of compressed wood strands. They are used in building and construction applications for both sub-flooring and exterior sheathing. Like plywood panels, OSB panels are a popular engineered wood product. They consist of cross-oriented layers of wooden strips that are bonded with a mixture of wax and resin adhesives, and then processed in a thermal press. Some OSB manufacturers treat these wood chips or flakes with borate compounds that are toxic to insects such as termites. OSB panels and panel materials may emit low levels of formaldehyde, but are often more popular than plywood structural panels.
Composite panels may also be made from layers of fabric that have been saturated in a thermoplastic or thermosetting resin (such as epoxy or phenolic). The fabric may be made from fibers of carbon, glass, metal, ceramic, or plastics. The saturated fabrics may then be stacked in layers (often at different planar angles) and pressed under heat to form a finished panel.
Many structural composite panels have a central core that may reduce the weight, density, and/or cost of the panel without a substantial degradation to stiffness or strength of the panel. These cores may be made of balsa, aluminum honeycomb, corrugated paper, foamed plastic, or similar materials and the saturated fabric is molded to each face of the core. Consequently, the high strength surface material serves as a skin to protect the core while the core often has higher impact resistance and allows for a stiff, lightweight structure.