Abstract
Dynamic compressive tests of 3D braided composites with different braiding angle were carried out in the longitudinal, transverse and thickness directions respectively using the Split Hopkinson pressure bar (SHPB). The results show that the compressive properties present obvious strain rate strengthening effects in all directions. The 20° and 45° braided composite are most sensitive to strain rates in the longitudinal direction. The composites present the features of brittle failure at high strain rates, especially in the longitudinal direction. The composites with larger braiding angle have weaker mechanical properties in the longitudinal and transverse directions but stronger mechanical properties in the through-thickness direction. The braid angle has the greatest impact on the longitudinal mechanical properties. The compressive stress-strain curves in the thickness direction were similar to the hysteresis curve for both the 30° and 45° braided composites. The compressive failure modes vary with the loading directions and strain rate.
Keywords
3D braided composites; dynamic compression; strain rate effect; braiding angle; loading direction; microscopic damage
