Analysis on longitudinal vibration law of deep sea stepped mining pipe

In order to study the longitudinal vibration law of the deep sea stepped mining pipe, the pipe is regarded as the beam element and discrete by the finite element method and the mathematical model is established. Based on the Wilson-θ integration method, the numerical calculation is performed and the longitudinal vibration law under different pipe lengths, pipe thicknesses, and towing speeds is obtained. The research shows that the vibration is the irregular oscillating motion, and the law of the vibration amplitude from the top to the bottom is to decrease first and then to increase. Under the same working conditions, increasing the total length of the mining pipe, the pipe thickness, and the towing speed will reduce the amplitude of the longitudinal vibration, but only when the total length of the pipe changes, will the position of the minimum vibration amplitude be changed. The pipe thickness and the towing speed cannot change the vibration frequency, while the pipe length can change the vibration frequency. When the same external damping is added, reducing the pipe length, pipe thickness, and towing speed will increase the vibration intensity attenuation value and enhance the damping effect.