Define the term "crush core" in composite materials.

The term "crush core" in composite materials refers to a lightweight core material that is specifically designed to provide strength and stiffness. It is commonly used in sandwich structures, where layers of composite material are bonded on either side of the crush core. This configuration allows for the efficient use of materials, maximizing the structural integrity while minimizing weight.

The crush core is typically made from materials such as foam or other lightweight substances that can withstand compressive forces without collapsing. Its properties enable it to absorb impacts and distribute loads effectively, which is essential in aerospace applications where weight reduction is crucial for performance and fuel efficiency. The crush core contributes to the overall rigidity of the composite structure while allowing for flexible design options.

Other options, such as coatings or reinforcement methods, do not accurately capture the essence of what a crush core is or its role within composite structures. The focus of the definition is specifically on the core material itself and its functional benefits within composite engineering.