Self-restoring damper based on complex deformation of heterogeneous materials

Self-restoring vibration damping damper integrating urethane compression, shape-memory wire tension, and lead block shear within a single cylinder

This technology is a self-restoring damper featuring a shaft that slides within an open-ended cylinder based on external forces. It includes a first damping unit compressed at both ends of the cylinder, a second damping unit that stretches around the cylinder circumference in response to that compression, and a third damping unit that undergoes shear deformation due to relative movement between the shaft and the cylinder. When the external force is removed, all three damping units return to their original shapes.

As the number of high-rise buildings and long-span bridges increases, research into vibration dampers to withstand earthquakes and typhoons has become active. However, existing self-restoring dampers that combine friction plates and shape-memory alloy rods have been difficult to adjust after manufacturing. Furthermore, because some use methods that dissipate vibration energy as frictional heat, the friction surfaces often remain displaced, making it fundamentally difficult for the damper to return completely to its original state.

In this technology, the first action plate moves with the shaft during tension, and the second action plate moves during compression, pressing the urethane blocks placed between them and the caps. Superelastic shape-memory wires connected between the two plates are configured to stretch in the same direction. Lead blocks inserted into the shaft mounting grooves through the cylinder mounting holes absorb additional energy through shear deformation. Since the number of wires and lead blocks can be selected and detached, damping capacity can be adjusted even after installation. It can be applied to vibration control devices for high-rise building frames, vibration control for long-span bridge expansion joints, and brace dampers for seismic retrofitting of existing structures. By having three different materials handle compression, tension, and shear to absorb shocks in stages, it returns to its original shape without friction, reducing the burden of repairing residual deformation after an earthquake.

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Key Features:

• A shaft provided inside an open-ended cylinder that slides according to external forces and deforms the first, second, and third damping units
• A first damping unit provided at both ends of the cylinder that is compressed according to the sliding of the shaft to dampen external forces and restores its shape when the external force is removed
• One or more second damping units disposed around the circumference of the cylinder that are stretched according to the compression of the first damping unit to dampen external forces
• A third damping unit provided between the shaft and the cylinder that undergoes shear deformation according to the relative movement of the shaft with respect to the cylinder to dampen external forces

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This invention was developed with support from the Ministry of Land, Infrastructure and Transport for the commercialization of multi-functional vibration reduction devices for pilotis structures capable of withstanding a magnitude 7.0 earthquake.

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