Investigation of the effect of adding carbon nanofibers on the improvement of the mechanical properties of single-lap composite bolted joints

The use of carbon nanofibers in industries is increased due to the improvement of the mechanical properties of composites. In the present research, by an extensive experimental program, the effect of adding carbon nanofibers to the single-lap composite bolted joint made of glass/epoxy on the mechanical properties of the joint was investigated. The failure mode of all joints was the bearing failure mode based on the ASTM D5961 standard. In this research, the factorial design was employed for the design of experiments. The stacking sequence and the volume fraction of carbon nanofibers were considered as the control factors and their effect on the stiffness, strength, and energy absorption of the joint were investigated. Also, a 3D finite element method was presented to investigate the effect of adding carbon nanofibers on the stiffness of single-lap composite bolted joints. To achieve this aim, four layups with different 45-degree layers were investigated. The present FEM model was validated by the experimental results and available theoretical model.