Fiber identification of braided composites using micro-computed tomography

Braided composites contain interwoven fibers that are embedded in a matrix material. Advanced measurement methods are required to accurately measure and characterize braided composites due to their interwoven composition. Micro-computed tomography (mu CT) is an X-ray based measurement method that allows for the internal structure of objects to be examined. High-resolution mu CT of braided composites allows for their internal geometry to be accurately measured. Braid samples were measured with a voxel size of 1.0 mu m(3), which resulted in a field of view of 4.904 x 4.904 x 3.064 mm(3). With this field of view, individual fibers within the braid yarns could be identified and measured. The scientific visualization software package Avizo and the XFiber extension was used to identify and measure braid yarn fibers from the collected mu CT measurements. Fiber properties such as orientation angles (phi and theta), curved fiber length, tortuosity, and fiber diameter were obtained. Additionally, finite element mesh geometries of the braid yarns within a braided structure were created. The presented methodology provides a roadmap for the accurate modeling of braided composite unit cell geometries using high-resolution mu CT data.