In order to analyze the low-velocity impact property and failure mechanism of multiaxial three-dimensional (3D) woven composites, and to study the effect of bias yarns in the structure on the impact damage of the composite, a multiaxial 3D woven composite with carbon fibers and epoxy resin was designed and manufactured. Then the low-velocity impact property of the composite was tested by using an Instron Dynatup 9250HV testing machine, and was compared with a three-dimensional (3D) orthogonal composite. The load and energy versus time curves with impact were collected by the testing machine. The failure mechanism of two kinds of composites were analyzed and compared by observing the appearance and internal impact fracture morphologies of the samples. Results show that the insertion of ±45° bias yarns make the multiaxial 3D woven composite have higher low-velocity impact resistance property and higher energy absorption property. It is found that partial fiber breakage and interlayer crack propagation are important damage mechanism. Morever, the impact damage of each yarn layer in the structure is affected by the axial direction of the yarn in this layer. The shape of the damaged area of 0° warp layer and 90° weft layer is similar to ellipse, and the long axis of ellipse is along the warp axis direction or the weft axis direction, while the -45° bias yarn and the +45° bias yarn are interacting on each other during the impact testing. When the +45° bias yarn layer and the -45° bias yarn layer are disposed adjacent to each other, the shape of the damaged area in the bias layer is simultaneously affected by axial direction of this yarn layer and the adjacent yarn layer, the impact damage area is approximately a parallelogram with a set of opposite sides parallelling to the -45° direction and the other set of opposite sides parallelling to +45° direction. © 2020, Materials Review Magazine. All right reserved.
