The effects of distance between fastener holes and hole diameter on tensile strenght of bolt and nut joints

In this study the effects of distance between fastener holes and fastener hole diameter for MIL A 46100 high strength armor steel samples, mounted by bolts and nuts, were investigated. Finite element analysis was performed for various forces for M10, M10-A, M10-B, M12, M12-A, M12-B configurations by using Nastran & Patran software. Tensile strength test was carried out only for M10 and M12 cases. Finally, it was observed that the deformation geometry of the test specimens was compatible with the shape obtained from FEM. Since the bearing area was higher at 12 mm diameter hole models and an increase in distance between fastener holes caused a decrease in stress concentration at the vicinity of the holes, the most effective configuration for carrying higher tensile load was found to be M12-B.