The invention provides an
underwater energy dissipation and seismic mitigation device with double umbrella surfaces symmetrical in the horizontal direction, and belongs to the technical field of
structural vibration control. The
underwater energy dissipation and seismic mitigation device is mainly applied to
vibration control of an ocean platform. The
underwater energy dissipation and seismic mitigation device comprises a
piston rod, a damping cylinder body, a cover plate, a
piston, a damping medium, a hinge device, a strut fixing device, a strut and a square
blade plate. The energy dissipation and seismic mitigation device is provided with a plurality of energy dissipation systems, when an external structure connected with the energy dissipation and seismic mitigation device vibrates horizontally, the damping cylinder body is fixed, so that when the
piston rod moves, the strut fixing device is driven to move, so that the strut is driven to move, the square
blade plate is driven by thestrut to slide in water, and certain damping force is provided through counter-acting force provided by the water. In addition, the external structure vibrates to drive the
piston rod of the device to axially move, so that the piston is driven to slide in the cylinder body, and
viscous damping force is generated. The underwater energy dissipation and seismic mitigation device has good underwaterenergy dissipation capacity, and is flexible and efficient.