Abstract: To study the phenomenon and influencing factors of the creeping vibration of an emergency gate, this study examines the vibration characteristics and determines the vibration type based on the prototype gate vibration response during gate closing operation. By analogy with dry friction self-excited vibration in tribology, we develop a mathematical model of closing stage vibration to invert the gate vibration response, and examine the influences of closing speed, gate mass, friction coefficient on the vibration behavior. The results show the creeping vibration of the gate is a special type of self-excited vibration with its amplitude growing gradually during gate closing. Transformation between dynamic and static friction of the gate and its tracks is the fundamental cause of creeping vibration, and the intensity of vibration response is proportional to panel water pressure and the difference between dynamic and static friction coefficients. Gate closing speed imposes great influence on gate vibration; a threshold closing speed, depending on the static friction coefficient, has been observed for judging the creeping vibration mode of the gate. Gate mass affects the initial deformation of steel ropes and the closing time, and thus influences the creeping vibration. The closure of the gate increases the length of steel ropes and decreases the system stiffness, leading to an increase in amplitude and period of vibration.

Key words: emergency gate, creeping vibration, nonlinear, self-excited vibration, numerical inversion, influence factor