Experimental characterization of dynamic tensile strength in off-axis carbon/epoxy composites

The tensile strength of unidirectional carbon fiber reinforced plastics under a high strain rate was experimentally characterized. A high-strain-rate test was performed using the tension-type split Hopkinson bar technique with a special fixture for the impact tensile specimen. In order to minimize the extension-shear coupling effect, an oblique tab technique was applied. The experimental results demonstrated that the tensile strength increase with strain rate. The strain rate effect of material principal directions on tensile strength are also investigated by the use of the rosette analysis and the strain transformation equations. It is found that the shear strain rate produces the more significant contribution to strain rate effect on dynamic tensile strength. The experimental results were compared with the tensile strength predicted based on the Hashin-Rotem failure criterion. The results imply that the application limit of this failure criterion exists for the prediction of the tensile strength under the dynamic condition. The fracture behavior translation from static to dynamic must be incorporated for more accurate prediction.