A type of two-degree-of-freedom vibration system with bilateral nonlinear constraints is established. Through the fourth-order Runge-Kutta numerical algorithm. the dynamic characteristics of the p/1 periodic motion of the system under low frequency excitation. the law of mutual transition and the corresponding law of the coexistence zone of gap and period are analyzed. https://cuttingedgecutleryco.shop/product-category/handcuff/