A 3D composite is a type of composite material that utilizes fiber preforms constructed with fibers arranged in complex three-dimensional structures.
Understanding 3D Composites
Unlike traditional 2D composites where fibers are typically layered in planes, three-dimensional (3D) composites incorporate fibers that are interconnected and extend through the thickness of the material. This distinct structural arrangement provides enhanced properties, although the provided reference focuses specifically on their construction.
Based on the definition provided:
- Fiber Preforms: At the core of a 3D composite is a fiber preform. This is the reinforcement structure before it is impregnated with a matrix material (like resin) to form the final composite part.
- Construction: These fiber preforms are built from yarns or tows. Yarns are continuous strands of fibers, while tows are bundles of filaments.
- Structure: The key characteristic is that these yarns or tows are arranged into complex three-dimensional structures, meaning the fibers are oriented not just in length and width, but also through the thickness.
How 3D Preforms are Created
The reference highlights several specific methods used to create these intricate 3D fiber arrangements:
- 3D Weaving Process: Interlacing yarns in three dimensions.
- 3D Knitting Process: Looping yarns together to form a 3D structure.
- 3D Braiding Process: Intertwining multiple yarns in a specific pattern to create a 3D form.
- 3D Lay of Short Fibers: Arranging discontinuous (short) fibers in a three-dimensional orientation.
These processes allow for the creation of a single, integrated fiber network that resists delamination (separation of layers), which is a common failure mode in 2D layered composites.
