“…A great number of theoretical and experimental studies have been done by many researchers (Guan et al, 2003;Li et al, 2004;Fan et al, 2013). In terms of the complexity of the model, most of the early models are uncoupled vibration models, like axial (Lubinski, 1988;Elsayed and Phung, 2005;Li et al, 2007), lateral (Beck and da Silva, 2010;Ghasemloonia et al, 2012) and torsional (Challamel et al, 2000;Besselink et al, 2011;Arjun Patil andTeodoriu, 2013a, Arjun Patil andTeodoriu, 2013b) vibration models. These simplified models allow researchers to understand how the single external excitations influence the vibration of drill string.…”