Predictions of Bending Modal Properties of the 3D Braided Composites with the Homogeneous Theoretical Model

In this work, the bending modal properties of three-dimensional (3D) braided composites were investigated with the experimental and numerical methods. Three braided angles were selected to study the braided angle effect on the modal behavior of 3D braided composites. According to the experimental parameters, a homogeneous model containing the interior, surface and corner representative unit cells of the braided composites were proposed to compute the elastic constants of each composite. Besides, the fiber breakage defects were introduced to the homogeneous model to improve the accuracy of predicting the modal behavior of the braided composite. The results indicate that the increase of the braided angle and the fiber breakage defects could apparently reduce the natural frequency of the braided composite. The modal properties simulated by the homogeneous models containing some fiber breakage defects could fit well with the corresponding experimental results. The proposed method to create the homogenous model can be used to predict the modal behavior of the 3D braided composites.