Influence of the strain rate on the uniaxial tensile behavior of 4-step 3D braided composites

The uniaxial tensile properties of 4-step 3D braided E-Glass/epoxy composites at quasi-static (0.001/s) and high strain rates (up to 2800/s) were tested with MTS and split Hopkinson tension bar (SHTB), respectively. From the stress-strain curves of the composites at various strain rates, it is shown that the 3D braided composite is a kind of the rate-sensitive material. The uniaxial tensile stiffness and failure stress increase with the increase of the strain rate, while the failure strain decreases. The fractograph of 3D braided composites depicts the 3D braided composites fail in a more brittle mode in tension at high strain rates. More experiments should be conducted to establish the constitutive equation of 3D braided composites at various strain rates.