Sliding Seismic Isolation Device With Double-Woven PTFE Slider
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Solution Overview
Problem
Conventional sliding seismic isolation devices face challenges with low contact pressure, leading to increased size requirements and higher costs, and variability in earthquake response due to high friction coefficient variations, making them less competitive and difficult to achieve high-performance seismic isolation.
Innovation Solution
A sliding seismic isolation device with a steel slider featuring a double-woven fabric layer containing PTFE fibers and fibers with higher tensile strength than PTFE, arranged on the sliding surfaces, achieving a contact pressure of 60 MPa and improved durability and slidability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the contact pressure of the slider is increased to reduce device size, then the device size and cost are reduced, but the friction coefficient variability increases leading to unstable earthquake response
Solution Approach 1:
The slider employs a composite material structure consisting of a steel base material combined with a PTFE-based friction surface layer. This composite structure enables the slider to maintain high contact pressure (60 MPa or higher) while the PTFE layer provides stable friction characteristics, resolving the contradiction between device size reduction and earthquake response stability.
Solution Approach 2:
The invention changes the friction surface material parameters by using PTFE (polytetrafluoroethylene) with specific physical and chemical properties. This material parameter change enables the friction surface to maintain consistent coefficient of friction even under high contact pressure conditions, thereby stabilizing earthquake response while allowing compact device design.
2Stress or pressure
If a steel slider is used to achieve high contact pressure, then the contact pressure increases to 60 MPa or higher, but the friction coefficient varies significantly causing unstable seismic isolation performance
Solution Approach 1:
The steel slider incorporates a composite structure where a PTFE-based friction layer is applied on the steel substrate. This composite material approach allows the slider to exert high contact pressure (60 MPa or higher) while the PTFE layer maintains stable friction characteristics, ensuring consistent seismic isolation performance despite the high pressure conditions.
Solution Approach 2:
The PTFE friction layer acts as a consumable element that can be replaced if worn. This approach allows the use of high-contact-pressure steel sliders while accepting that the friction surface may degrade over time, maintaining performance consistency during the service life of the friction layer.
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 solution provides high seismic isolation performance with a contact pressure of 60 MPa, reduced response acceleration, and controlled response displacement, enhancing durability and cost-effectiveness while maintaining high seismic isolation performance.
Implementation Method 1
the operation performance of the upper and lower shoes is dominated by the coefficient of friction between the upper and lower shoes and the slider interposed between them
Implementation Method 2
Each of the upper and lower surfaces of the slider has a double-woven fabric layer, the double-woven fabric layer containing PTFE fibers and fibers with higher tensile strength than that of the PTFE fibers
Data Source
AI summary
Provided is a high-performance sliding seismic isolation device with a slider that realizes a contact pressure of 60 MPa. The device includes an upper shoe 1 and a lower shoe (2) having sliding surfaces 1a and 2a with curvatures, respectively; and a columnar steel slider (7) disposed between the upper shoe (1) and the lower shoe (2), the slider having an upper surface 4a and a lower surface 4b that are in contact with the upper and lower shoes, respectively, and have curvatures. The upper surface 4a and the lower surface 4b of the slider (7) have double-woven fabric layers (5) and (6), respectively, each double-woven fabric layer containing PTFE fibers and fibers with higher tensile strength than that of the PTFE fibers, and the PTFE fibers being arranged on the sides of the sliding surfaces 1a and 2a of the upper shoe (1) and the lower shoe (2).