The Geometric Characterization of Three Dimensional (3D) Braided Fabrics and Computer Application of Their Unit Cells

In this study, 3D fully and axial braided preforms were developed. They were investigated based on number of layers and number of steps which is processing parameter. It was understood that out of plane angle somehow influenced by the number of layers but, it was independent from the structure width. The structure density was not affected by the number of layers and structure width. Yarn lengths were affected by structure layers and the increasing the layer numbers caused the increasing the yarn lengths in the structure. The processing parameters in the single step case, the layers in the structure were interconnected all together to result integrated preform. In the double step case, yarn sets in 3D braiding were intertwined to each other and lock the yarn sets in each in-plane direction whereas there was no interconnection such layer through the out of plane direction. Yarn connection was occurred only both edges of the structures so that each layer lock all together. As a result, there was an empty pocket between each single braided layer. Similar results occurred in the 3D axial braiding in where each layer in the structure was locked to form as if the triaxial layer to the in-plane direction but, there was no interconnection between the layers to the out of plane direction. The yarn angle, length and density in each developed structure were affected by structure jamming conditions