Multi-stage energy dissipation damping device and offshore platform pile leg structure

The invention provides a multi-stage energy dissipation damping device which comprises a center pipe, damping units and connecting units, and fixing holes are formed in the two ends of the center pipe; the damping units are arranged at the two ends of the center pipe and comprise a plurality of slotted plates attached to the outer wall of the center pipe in the circumferential direction, each slotted plate is provided with an extending arm extending section, the extending direction is the direction from the middle of the center pipe to the two ends, the front ends of the arm extending sections are located outside the two ends of the center pipe, and the slotted plates are provided with fixing holes corresponding to the fixing holes of the center pipe. The connecting units penetrate through the fixing holes to fix the damping units to the two ends of the center pipe. The invention further provides an offshore platform pile leg structure, the offshore platform pile leg structure comprises the multi-stage energy