What is a sandwich composite?

Composite materials are made from two or more constituent materials with significantly different physical or chemical properties, that when combined, form an overall structure with characteristics different from the individual components.

Sandwich-structured composites are a special class of composite materials, fabricated by attaching two thin, strong and stiff skins to a lightweight and relatively thick core. The core is bonded to the skins with an adhesive. A variety of core materials is used in sandwich structures.

The sandwich construction has a very high stiffness-to-weight and high bending strength-to-weight ratio. As a result, sandwich components achieve the same structural performance as conventional materials with much less weight.

The skins of a typical sandwich composite are thin, strong and stiff, and the core is light and structurally strong enough to keep the skins in their relative positions under loading.


The benefits of sandwich composites

Reduced weight
Sandwich composites provide excellent mechanical properties to much lower weight than traditional monolithic materials, such as steel. They can also be engineered with extreme precision to their loading requirements.

Less weight translates into better fuel efficiency, higher speed, higher payload, longer range and lower transport and installation costs.

 

 

With the same criteria for deflection, the weight savings with sandwich design is almost 90%. (This example compares standard materials.)


Increased strength



Sandwich composites can be designed to be both strong and light, which is important for applications that require a very high strength material at the lowest possible weight. Also, metals are equally strong in all directions. When something is built with metal, and greater strength is required in one direction, the material usually must be heavier, which adds weight. Composites can be engineered to be strong in a specific direction.

Design flexibility

Composites can be molded into almost any shape, which gives full design freedom. When building sandwich composite structures, the materials are shapeable until the last stage of production in which they get their final shape. This allows for non-linear and smooth designs, which can be done not only for esthetic but also aerodynamic reasons.

Corrosion resistance
Composites resist damage from severe weather and harsh chemicals. Structures built with sandwich composites need minimal maintenance.

Reduced environmental impact
Using lightweight sandwich constructions benefits in many ways the environment. Due to their low-density properties, the cores themselves require a small amount of raw materials, which also means that relatively little has to be transported from the source to the construction site.

Sandwich design enables lightweight construction and flexible, aerodynamic design that reduce fuel consumption and emission throughout the entire lifetime of the application.

Composite materials are also very weather and corrosion-resistant, which means a minimum of maintenance and long life spans. Consequently, very little or no additional natural resources are needed to repair or renew the applications.

An additional benefit is that sandwich solutions provide both thermal and acoustic insulation, thus increasing comfort and saving insulation materials.

Nonmagnetic
Composites don’t contain any metal, therefore they are not magnetic and can be used around sensitive electronic equipment.

Radar transparent
Radar signals pass right through composite structures, which makes composites ideal for use with radar equipment, whether on the ground or in the air.

Low thermal conductivity

 

Composites are good insulators since they don’t easily conduct heat or cold. They can be used in buildings for doors, panels and windows where extra protection is needed from severe weather.

Additional benefits
Fire, Smoke & Toxicity (FST)
Sound insulation
Very low water absorption
Ease of repair
Dielectric properties
Component Integration

For more information about sandwich composites and the benefits of using them, download our Diab guide to core and sandwich.