Smart Friction Pendulum System with SMA Wires for Seismic Recovery
Solution Overview
Problem
Conventional friction pendulum systems (FPS) are unable to fully restore the original position of civil infrastructure after seismic events, resulting in residual deformation and changes to the structure's shape.
Innovation Solution
A smart friction pendulum system incorporating shape memory alloy (SMA) wires, which absorb energy during seismic loads and utilize SMA's recovery capability to restore the system to its initial position, is integrated between the foundation and base mass of buildings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional friction pendulum systems are used to dissipate seismic energy, then energy dissipation is achieved, but the system cannot fully restore the original position after seismic events
Solution Approach 1:
The patent introduces shape memory alloy wires that change their physical state in response to temperature changes. The SMA wires transform from austenite to martensite structure when cooled during seismic events, absorbing energy, and then transform back to austenite when heated, restoring the original position. This parameter change enables both energy dissipation and full position restoration.
Solution Approach 2:
The patent combines conventional friction pendulum components with shape memory alloy wires to create a composite system. The SMA wires are integrated into the friction pendulum structure, allowing the system to leverage both the friction-based energy dissipation of conventional FPS and the shape-memory-based recovery capability of SMA materials.
2Loss of energy
If conventional friction pendulum systems are used, then energy dissipation function is provided, but residual deformation remains in the foundation
Solution Approach 1:
The shape memory alloy wires provide self-service recovery capability. When the seismic load is removed and temperature increases, the SMA wires automatically transform back to their original shape without external intervention, pulling the foundation back to its initial position and eliminating residual deformation.
Solution Approach 2:
The SMA wires utilize temperature-induced phase transformation to recover the building's original shape. The change in material properties from martensite to austenite phase with temperature increase enables automatic shape recovery and elimination of residual deformation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The smart FPS system effectively dissipates seismic energy, preserves the structural integrity of buildings, and fully recovers to its original position after seismic events, enhancing the lifespan and stability of civil infrastructure.
Implementation Method 1
a plurality of shape memory alloy (SMA) wires (40)... The SMA wires (40) also absorb the energy when it goes to the inelastic reversible phase
Implementation Method 2
The system dissipates the energy transmitted to the main structure... energy dissipation via friction... The system dissipates energy by providing friction between sliding material and sliding surface
Implementation Method 3
The curved surface on the spherical plates help the slider and spherical plates to partially move back to the initial position
Data Source
AI summary
A smart friction pendulum system including an upper spherical plate and a lower spherical plate each having a sliding surface, a slider positioned between the upper spherical plate and the lower spherical plate, and a plurality of shape memory alloy (SMA) wires each having a first end attached to the upper spherical plate and a second end of attached to the lower spherical plate. The smart friction pendulum system is configured to be attached between the foundation and base mass of a building to preserve the superstructures under the lateral loads. While the lateral loads move the plates side to side, the system dissipates energy by providing friction between sliding material and sliding surface. The SMA wires also absorb the energy when in inelastic reversible phase. The embedded diagonal SMA wires make the whole system recover the initial position fully.