Experimental investigation of mode veering phenomena in a bolted connection

Abstract. Mode veering phenomena, sometimes accompanied by mode localization, refers to the sudden and abrupt changes in the trajectories of eigenvalues in a system, often caused by small variations in system parameters or boundary conditions. In this paper, mode veering phenomena is studied with the focus on the dynamics of bolt connection geometry. A combination of experimental and analytical modeling is used to identify and validate the conditions under which veering occurs in bolted connections. The parameter varied here is the length ratio of the shank and protruding end of a bolt, which serves to characterize the bolt’s geometry. The experimental results demonstrate that the observed behavior corresponds well with the analytical model, indicating the presence of localized modes. In particular, the mode shape variation showed consistency with the model's predictions. The implications of these findings with respect to the agreement between the model and observed experimental results are discussed.