Quasi-static and fatigue tensile behavior of a 3D rotary braided carbon/epoxy composite

Abstract

This paper presents an experimental study of the quasi-static and fatigue behaviour of a three-dimensional braided carbon/epoxy composite. The study involves a three-dimensional braided carbon preform and composite samples produced at 3TEX Inc. on their 576-carrier rotary braiding machine. The first part of the paper describes the preform and composite sample fabrication procedures, the fiber volume fraction determination and the porosity evaluation using micro-computed tomography three-dimensional observation. The second part is devoted to experimental study of the quasi-static tensile response of the material, including the acoustic emission monitoring and the microscopic damage detection. The third part is dedicated to the fatigue tensile–tensile behaviour illustrated by the fatigue life curve and the micro-computed tomography images of the damage imparted after different number of cycles. The fourth part presents results of the quasi-static tensile tests of preliminarily cyclically loaded specimens. These results provide significant insight into the influence of the damage imparted during fatigue loading on the subsequent quasi-static behaviour.