“…For vibrations of structures prone to unilateral contact, families of periodic solutions are indicative of resonance frequencies and behaviours and are, in fact, referred to as nonsmooth modes of vibration (NSMs) [1][2][3][4]. In essence, NSMs are families of periodic motions of the unforced and undamped investigated structure [5][6][7][8]. In the present work, we focus on nonsmooth modal analysis of the bar of varying (cross-section) area in unilateral contact with a rigid structure.…”