Define the term "crush core" in composite materials.

The term "crush core" in composite materials refers to a lightweight core material that is utilized to enhance the strength and stiffness of composite structures. This core material is typically made from materials like foams or honeycomb structures, which provide a significant amount of rigidity without adding excessive weight. The crush core acts as an intermediate layer that absorbs loads and distributes forces evenly across the composite structure, improving its overall mechanical properties. In applications like aerospace, where weight reduction is critical, using crush core materials allows engineers to design structures that are both strong and lightweight, ultimately contributing to better performance and efficiency.

Other options do not relate to the definition of crush core in composite materials. For instance, coatings, reinforcement methods for metal structures, and curing processes are distinct concepts in materials science and engineering that do not define the specific function and purpose of crush core in composites.