Effect of riveting displacement on the mechanical behavior of CFRP bolted joints with elliptical-head non-lug self-locking rivet nut

The increasing integrated manufacturing of composite components required efficiency and reliable one-sided connection. In this paper, the effect of riveting displacement on the mechanical behavior of CFRP single-lap bolted joints with a new type of one-sided connected fastener named elliptical-head non-lug self-locking (EHNL) rivet nut was studied. A three-dimensional FE model considering CFRP damage and nut material plastic deformation was developed. The whole process of the joint from nut forming to static tensile could be simulated by the FE model. The unique load-drop phenomenon in the tensile response of the joint with the EHNL rivet nut was explained. The forming quality, tensile, and fatigue behavior of joints and progressive damage of CFRP with five riveting displacements were comprehensively studied by experiments and numerical simulations. The results showed that the tensile strength increased with the increase of the riveting displacement, while the fatigue life decreased due to the larger residual stress and damage of CFRP caused by the larger riveting displacement in the nut-forming process. The fatigue life of the joint should be considered more significantly in the selection of the riveting displacement.