Investigation of mechanical performances of composite bolted joints with local reinforcements

Four different local reinforcement schemes used in composite bolted joints were studied. In numerical study, a set of 3-D failure criteria was used and the progressive failure analysis was implemented via user-defined subroutine vectorized user-material (VUMAT), which was programmed by the commercial finite element (FE) software ABAQUS. In the experiment, test specimens were manufactured with different local reinforcement schemes, and the mechanical performances of these specimens were tested under tensile loads. Failure modes of these specimens were observed and mechanical performances of test specimens with local reinforcement were studied. It was found that the numerical results agreed well with the experiment. It was also found that local reinforcement schemes influenced the mechanical performances of bolted joints obviously and that the tensile strength of composite bolted joints could be improved significantly by burying laminate slices.