Abstract: In order to analyze the influence of the parameters of composite connectors, optimize the ratio between conventional parameters, and improve the structural economy and practicability, the influence of tensile str-ength on the significant connection parameters in the three manufacturing and assembly stages of plate thickness, end-diameter ratio and preload was studied. Combined with the UMAT subroutine, the finite element model of CFRP bolted joints was established, and the static tensile failure and SEM damage observation tests were carried out to verify the finite element model. On this basis, based on the Box-Behnken design, combined with the response regression equation, 3D response surface and contour map, the joint response model of bearing strength and influencing factors was established, and the three parameters were analyzed from the aspects of single factor and multi-factor interaction, and the determined coefficient R² of the joint response model was 0.984 7, Adj R² is 0.957 1, Pred R² value is 0.794 4, the model fitting effect and prediction ability are better; the analysis results show that plate thickness is the most significant single factor affecting the bearing strength among the three parameters, and the interaction between plate thickness and end-diameter ratio has the most significant effect, and the model gives an optimization of plate thickness, end-diameter ratio and preload, and the error between the predicted strength and the finite element result is 0.37%, indicating that the established joint response model has a good strength prediction ability.

Key words: composites, bolted connections, response surface method, interactions, optimization