Multi-scale characterization analysis combined with improved cells model for bearing performance of double-shear single bolted joint laminate structures

In order to improve the reliability and load carrying capacity of bolted joint laminate structure, the multi-scale numerical model combining with improved cells model and considering the failure of constituent materials was created based on ABAQUS software and user subroutine(USDFLD). Based on the model, the mechanical properties of the double-shear single bolted joint laminate structures was characterized, and the effects of layup form and geometry on the properties of bolted joint structure were researched. The predicted results using the model were in good agreement with the testing results. The results show that the bearing strength of quasi-isotropic bolted joint laminate structure was higher than that of orthotropic bolted joint laminate structure, and the failure mode of the former was bearing failure, but that of the latter was shearing failure. The shearing failure will result in the decrease of structure bearing capacity. So it should be avoided during the design. When the ratio of edge to diameter for laminate is greater than 3, the bearing strength converges to a stable value for the bolted joint structure with different ratio of width to diameter. But as for the bolted joint structure with the same ratio of edge to diameter, the bearing strength increases with the increase of the ratio of width to diameter. It also should be given consideration during the process of bolted joint structure design.