Evaluation of the Load-Bearing Behaviour of Bolts and Lockbolt Systems Under Combined Tension and Shear Loading

In this paper, experimental studies on the load-bearing behaviour of tensile test pieces, bolts, and lockbolts subjected to combined tension and shear loading are presented. The results are compared to the design approaches from different standards and evaluated in terms of reserves and uncertainties. In general, a notch-independent behaviour is observed for the specimens with smooth, threaded, or grooved shank. It turns out that the description of the load-bearing behaviour by linear interaction models is unreliable. Although the testing results are arranged in an arc shape in the interaction diagram, they are located on the uncertain side of the quadratic interaction model, which is valid according to the standard VDI 2230 part 1. Especially due to the lack of consideration of the tensile load-bearing capacity of the cross section in the shear plane, the load-bearing potential is not fully utilised by the interaction approaches of some standards.