Frictional load transfer of high strength bolted connection in post-slip behavior focused on bolt preload

Abstract

Bolted connection usually carries the load by frictional load transfer in not only pre-slip behavior but also post-slip behavior. Bolt preload is an important factor because the preload is related to slip resistance. In past experimental research, the ultimate maximum resistance of the bolted connection tightened the bolt without bolt preload was almost the same as that of the connection tightened the bolt with preload. However, the mechanism is unknown yet. In this study, finite element analysis was conducted to clear the mechanism. The bolt axial force during pre-slip and post-slip behavior is changed, and the bolt axial forces of bolted connections tightened the bolt with and without preload are almost the same in ultimate behavior even the bolt preload is different. As a result, the ultimate resistances are almost the same. This result suggests that the loss of the bolt axial force of a part of bolts reduces the slip resistance, but the influence on the ultimate resistance is small.