(a) Briefly describe sandwich panels. (b) What is the prime reason for fabricating these structural composites? (c) What are the functions of the faces and the core?

Sandwich panels are lightweight and strong structural composites that consist of two thin, stiff face skins bonded to a lightweight, flexible core material. They are used in various industries, including aerospace, automotive, and construction, due to their high stiffness-to-weight and strength-to-weight ratios, thermal and acoustic insulation properties, and resistance to various environmental factors.

The prime reason for fabricating sandwich panels as structural composites is to obtain a material with high structural performance, specifically high stiffness and strength, while minimizing weight. The combination of stiff face skins and lightweight core material allows the sandwich panel to resist bending and buckling loads, making it suitable for various applications where lightweight, strong, and stiff structures are critical.

The faces of a sandwich panel serve several functions: 1. Provide stiffness: The stiff face skins resist bending and contribute to the overall stiffness of the panel. 2. Carry in-plane loads: The faces carry tensile, compressive, and shear loads in the plane of the panel. 3. Protect the core: The face skins also serve as a barrier to protect the core material from environmental factors, such as moisture or temperature, which may weaken the core material. The core of a sandwich panel also has several functions: 1. Provide stability: The core helps maintain the distance between the face skins, ensuring the sandwich structure's stability when exposed to loads. 2. Enhance overall stiffness: The core provides resistance to shear stresses and enhances the overall stiffness of the panel. 3. Insulation properties: The lightweight core material often provides thermal and acoustic insulation properties, making sandwich panels suitable for various applications where these properties are essential, such as in buildings and vehicles.