Evaluating the structural parameter on the forming quality and tensile property of CFRP bolted joints with one‐sided connected rivet nut

Abstract As a kind of one‐sided connected rivet nut, the elliptical‐head non‐lug self‐locking (EHNL) rivet nut can ensure the gap‐free connection and realize the long life and reliable assembly connection of the aircraft. In this paper, the effect of the countersink angle and hole diameter of the nut on the forming quality and static tensile property of the joint is systematically studied. The results show that the effect of the countersink angle on the residual stress and damage of the CFRP plate is caused by the special mechanism that the material is easy to flow to the short‐axis barrel wall area when the nut is formed, and is also affected by the layup. While the effect of hole diameter on the residual stress and damage of CFRP plate is determined by the different deformation behavior of the rivet nut. As for the static tensile strength, the effect of the countersink angle is determined by the residual stress of the CFRP plate caused by the nut forming. But the effect of the hole diameter is small. Only when the hole diameter is 8.58 mm, the tensile strength is slightly reduced by 5.48% due to the large residual stress caused by the nut forming. Considering the forming quality and tensile property, the countersink angle of 45° and hole diameter of 8.46 mm are recommended for the specimen in this study. Highlights Structural parameters on forming quality and tensile property is studied. The influence mechanism on forming quality and tensile property is revealed. Recommended values of structural parameters are provided.