“…CONTACT Khaldoon F. Brethee khaldoon.brethee@hud.ac.uk,khaldon77m@hotmail.com Moreover, vibration relating to gear spalling or tooth breakage (TB) (Begg et al, 2000;Chaari, Baccar, Abbes, & Haddar, 2008;Jia & Howard, 2006;Lu, Gong, & Qiao, 2012), tooth crack (Chen & Shao, 2011;Mohammed, Rantatalo, & Aidanpää, 2015;Tian, Zuo, & Wu, 2012;Wu, Zuo, & Parey, 2008), tooth surface pitting and wear (Choy, Polyshchuk, Zakrajsek, Handschuh, & Townsend, 1994;Ding, 2007aDing, , 2007bFlodin, 2000) have been used to study these faults in terms of gear fault detection. In general, these models included both translation and rotational motions to show the fault effects on the gear dynamic characteristics.…”