At the heart of every high-performance composite structure lies an unsung hero—the core material. Much like the hidden framework within architecture, core materials serve as the silent strength behind lightweight yet incredibly stiff designs. From aerospace components slicing through the skies to cutting-edge marine vessels riding the waves, core materials are the foundation that allows composites to defy gravity and endure extreme forces. But what exactly are these mysterious materials that turn resin and fiber into marvels of modern engineering?