“…One of the two oscillators connected to an excitation system intermittently impacts with an obstacle fixed on the thick steel wall associated with different gap sizes. Along with the requirement of engineering application and the increasing thorough of basic research on nonsmooth dynamics, vibro-impact dynamics has been applied to a wide range of practical mechanical systems for finding the correlative relationship between dynamic performance and model parameters, such as wheel-rail impacts of railway coaches [56,57], vibrating hammer [58], pile driver [59,60], ground moling dynamics [61], fly-wheel model of the bouncing ball [62], link mechanism [63], ultrasonic percussive drilling [64,65], vibro-impact capsule system [66], pressure relief valve [48], Jeffcott rotors with bearing clearance [67][68][69], impact dampers [70,71], excited pendula with impacts [72], vibro-impact drilling [73], gears [36][37][38][74][75][76][77]. The dynamical models designed in Refs.…”