Influences of weave parameters on the mechanical behavior and fracture mechanisms of multidirectional angle-interlock 3D woven composites

As a novel 3D textile composite material, the effects of weave parameters on the mechanical performance of the multidirectional angle-interlock 3D woven composites directly determine the final engineering application. In this paper, three multidirectional angle-interlock 3D woven preforms with different layer stacking sequences or bias orientations were designed and manufactured. Computerized tomography (CT) scan was used to capture the typical internal architecture of the composites. The composite specimens were respectively examined with tension in the warp and weft directions and the full-field strain distributions during the tests were recorded using the digital image correlation (DIC) system. Additionally, the 3D microscopy was adopted to characterize the ultimate fracture surfaces. It was concluded that the composites within [+theta/0/0/-theta] stacking sequence exhibited enhanced tensile strength, and the failure morphology of three composites were sensitive to their corresponding weave parameters. The stacking sequence had little effect on the surface strain distributions of multidirectional angle-interlock 3D woven composites. However, the bias orientation had a great influence on the strain distributions for the loading case in the weft direction. This study has provided the basis for the structural design and application of multidirectional angle-interlock 3D woven composites.