Health assessment of a multi-bolted connection due to removing selected bolts

In the paper, experimental studies of an asymmetric preloaded seven-bolted connection are presented. The tightening process of the connection was carried out with a wrench, monitoring the values of the bolt forces with a calibrated strain gauge measuring system. Two methods of bolt tightening were tested: in one and several passes. After all bolts were tightened, the selected bolts were removed, simulating bolt failure under the loading conditions of the connection. The influence of the method and sequence of bolt tightening on the distribution of bolt forces values after the introduction of failure states of some bolts was investigated. The results were statistically processed and presented in the form of graphs showing the distributions of normalised bolt forces values for all the considered failure cases.