SMA Superelasticity-Assisted Slider for Seismic Isolation
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Solution Overview
Problem
Existing aseismic isolation systems have not been widely adopted in construction practices, despite their potential for enhancing earthquake resilience, due to limitations in effectiveness and practical application.
Innovation Solution
The use of shape memory alloy (SMA)-based superelasticity-assisted sliders (SSS) that allow building structures to shift horizontally and vertically during earthquakes, isolating them from ground movements and automatically recentering once the seismic activity ceases, integrated with various geometric configurations for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional elastomeric or sliding bearings are used for seismic isolation, then the structure can shift horizontally during earthquake, but the system lacks effective self-centering capability and automatic recentering after earthquake
Solution Approach 1:
The patent utilizes the phase transformation properties of shape memory alloys, changing their mechanical parameters (stiffness, strength) through temperature or stress-induced martensitic transformation. This enables the isolator to provide both flexibility during earthquake and automatic self-centering capability after the event, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The invention combines shape memory alloy elements with traditional bearing components to create a composite seismic isolation system. The SMA provides superelasticity and self-centering functionality, while the traditional bearing components handle load support and friction-based isolation, achieving enhanced reliability without proportionally increasing system complexity.
2Reliability
If advanced aseismic isolation systems are implemented, then earthquake resilience is enhanced, but maintenance costs increase and practical application becomes difficult
Solution Approach 1:
The patent divides the seismic isolation system into modular components including replaceable SMA wire bundles, friction elements, and structural components. This segmentation enables easier manufacturing, installation, and maintenance, making advanced aseismic isolation more practically applicable while maintaining high earthquake resilience.
Solution Approach 2:
The design incorporates replaceable SMA wire bundles that can be exchanged after reaching their deformation limit or showing signs of degradation. This approach allows the use of advanced materials for high reliability while managing maintenance costs through targeted replacement rather than complete system overhaul.
3Reliability
If shape memory alloy elements are used for automatic recentering, then the building structure recenters to original position after earthquake, but the system requires complex geometric configurations and arrangements
Solution Approach 1:
The patent designs the SMA elements to perform multiple functions simultaneously: providing superelastic damping during earthquake, enabling automatic self-centering after earthquake, and serving as structural reinforcement. This multi-functionality reduces the need for separate geometric configurations dedicated solely to recentering, thereby reducing overall device complexity.
Solution Approach 2:
The system utilizes the dynamic phase transformation characteristics of shape memory alloys that allow the material to adapt its mechanical properties in real-time during and after earthquake. This dynamic behavior enables automatic recentering through the material's inherent properties rather than complex mechanical geometric configurations.
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 SMA-based SSS systems provide improved integrity, redundancy, and maintainability, reducing maintenance costs and enhancing the resilience of structures against earthquakes by effectively isolating buildings from damaging ground motions and ensuring self-centering capabilities.
Implementation Method 1
shape memory alloy (SMA)-based superelasticity-assisted slider (SSS)
Data Source
AI summary
A system and method of isolating a building structure from ground movement including centering a building structure in a first position relative to a building foundation, securing a first portion of a super-elastic slider system (SSS) to the foundation, securing a second portion of the SSS to the structure. The SSS includes at least one shape metal alloy (SMA) element extending between the first portion and the second portion. The at least one SMA element having an initial shape. Moving the foundation during a ground movement and shifting the structure in at least one of a horizontal and a vertical direction to a second position, including flexing the at least one SMA element to a secondary shape, and automatically recentering the structure to the first position including retracting the at least one flexed SMA element to the initial shape.