Forming Analysis of Internal Plies of Multi-Layer Unidirectional Textile Preforms using Projectional Radiography

摘要

The mechanical properties of fiber reinforced composites strongly depend on the fiber orientations that are created during preforming. Fiber orientations of inner plies of a multi-ply composite structure cannot be analyzed easily, especially for uniaxial unidirectional non-crimp fabric preforms. A novel approach is presented that uses photogrammetry software for optical forming analysis and projectional radiography (x-ray) for image generation. The process of applying a grid of dots with a contrast enhancing color onto the rovings of the fabric and the use of a computer tomograph for creating the images is described. As a result, full-field strain data, shear angles and fiber orientations of an inner ply of an 8-ply unidirectional preform were acquired. Fiber orientations of the analyzed inner ply are compared with the outer plies.