Experimental and numerical investigation of open-hole tensile properties and damage mechanisms of 3D woven composites under weft-loading

摘要

For 3D woven composites used in the structural applications, the open-hole mechanical performance is of critical concern for the components in service. In the present study, the circular notched 3D woven composite (N-3DWC) plates with three different apertures were prepared, and the effects of notch size on the tensile properties were investigated by experimental and numerical methods. Digital image correlation technique was used to record the full-field strain distributions, and the micro computed tomography was applied to evaluate the failure fractures. Based on the developed macro-meso coupling model of N-3DWC, the open-hole tensile strength and failure mechanisms were predicted and analyzed, and the model was validated with the experimental results. The results showed that the stress-strain curves of all N-3DWC specimens were basically linear in the initial loading stage. The notch size had little effect on the tensile stiffness of notched plates, while the tensile strength decreased with the increasing aperture. The stress concentration mostly occurred at the hole edge, and the distribution width was approximately equal to the notch diameter. As the aperture increased, the main failure mode of weft yarn changed from fiber pull-out to breakage, and the contour of damaged region changed from to convex to concave.