Study on the torsion behavior of 3-D braided composite shafts

Abstract The structural parameters of three-dimensional (3-D) braided composites have important influence on their mechanical properties. The torsional properties of the 3-D braided composite shafts with braiding angles of 25°, 35° and 45° were tested by MTS809. Based on the micro-structure of 3-D braided composite material, unit cell model was established, and the failure process of 3-D braided composite transmission shaft under torsion was studied by finite element method. The results show that the shear resistance of the specimens increases with the increase of braiding angle, and the specimens still have a certain bearing capacity after unloading. The simulation results show that the damage of the specimens first appears at the fiber/matrix interface. With the increase of load, the damage of the matrix expands and connects between the interfaces, and finally leads to the failure of the specimens. The failure of small braiding angle specimens is mainly caused by the accumulation of matrix damage, while the fiber damage of large braiding angle specimens increases, and the deformation is more consistent with the experimental results.