Sliding Pendulum Seismic Isolator With PTFE Wear Layer
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Solution Overview
Problem
Conventional anti-seismic isolators of the sliding pendulum type face issues with geometrical inaccuracies, wear, water stagnation, and increased weight due to the use of stainless steel caps, which lead to inefficient energy dissipation and potential corrosion, especially when friction coefficients are increased.
Innovation Solution
The anti-seismic isolator replaces the stainless steel cap with a laminar sliding layer made of dry lubrication polymeric material directly applied to the anchoring and strike plates, ensuring improved geometrical accuracy, reduced wear, and enhanced durability, while preventing water stagnation and offering anti-corrosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a stainless steel cap is used as the sliding surface, then the friction coefficient can be increased to improve energy dissipation, but geometrical inaccuracies and wear occur due to plastic deformation tolerances
Solution Approach 1:
The patent replaces the stainless steel cap with a PTFE-based sliding layer that is applied directly to the steel plate. The PTFE layer can be replaced or reapplied without replacing the entire steel plate, effectively creating a disposable/wearable surface layer that protects the expensive steel substrate while maintaining sliding functionality.
Solution Approach 2:
The invention creates a composite structure by applying a PTFE-based polymer layer onto a steel plate substrate. This combines the low friction properties of PTFE with the structural strength and geometric precision of steel, achieving both low wear and high manufacturing precision.
2Ease of operation
If a stainless steel cap is used, then the sliding surface is provided, but water stagnation and corrosion occur in the unsealed gap
Solution Approach 1:
The patent uses a thin PTFE-based laminar layer that completely covers the sliding surface and extends to the edges of the steel plate. This thin film creates a seamless surface that prevents water from penetrating into gaps or crevices, eliminating water stagnation and corrosion risks.
Solution Approach 2:
The PTFE coating acts as a protective sacrificial layer that can be replaced if worn or damaged, protecting the underlying steel plate from corrosion and water damage throughout its service life.
3Stability of the object's composition
If the stainless steel cap is not rigidly fastened to allow deformation, then buckling is avoided during swinging movement, but water stagnation occurs in the created gap
Solution Approach 1:
The PTFE-based laminar layer is thin and flexible enough to accommodate the swinging movements and deformations of the steel plate without buckling, while simultaneously providing complete surface coverage that prevents water from entering any gaps.
Solution Approach 2:
The PTFE layer acts as an intermediary between the steel plate and the sliding pad, allowing relative movement and deformation while maintaining a continuous protective barrier against water penetration.
4Loss of energy
If the stainless steel cap is used with painted surfaces, then friction can be increased above 7-8%, but sliding occurs between the cap and paint rather than the intended surfaces
Solution Approach 1:
The PTFE-based sliding layer is applied directly to the steel plate without requiring an intermediate paint layer. This creates a consistent, reliable sliding interface between the PTFE-coated steel plate and the sliding pad, ensuring predictable friction-based energy dissipation.
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
This solution results in a more accurate, durable, and lightweight anti-seismic isolator with improved energy dissipation capacity and reduced production costs, maintaining performance without the need for additional mechanical coupling systems.
Implementation Method 1
at least one of the anchoring plate and the strike plate has an outer face in contact with the sliding and dissipation pad, entirely or completely coated with a laminar sliding layer which also serves the function of protection against corrosion, which is made of dry lubrication polymeric material
Implementation Method 2
a sliding and dissipation pad (or block) made of thermoplastic or thermosetting plastic material, arranged in simple support against the anchoring plate and the strike plate between which it is interposed in such a way to swing freely... to dissipate the kinetic energy transmitted to the elevated structure itself
Data Source
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AI summary
A dissipative anti-seismic isolator (1) of the sliding pendulum type, comprising an anchoring plate (2) adapted to be arranged close to a foundation structure, a strike plate (3) arranged above the anchoring plate (2) along a linear axis (Y) and adapted at least to help to support an elevated structure to dissipate the kinetic energy transmitted thereto by a natural phenomenon or a human-caused event and provided with a high release of total energy; a sliding and dissipation pad (4) arranged in simple support against the anchoring plate (2) and the strike plate (3) between which it is interposed in such a way to swing freely on the anchoring plate (2) and the strike plate (3) according to one or more random side directions, orthogonal to the linear axis (Y), alternately between a first position, taken on in the absence of the natural phenomenon or the human-caused event, in which the sliding and dissipation pad (4), the anchoring plate (2) and the strike plate (3) are substantially coaxial to one another, and a plurality of second positions, taken on while the natural phenomenon or the human-caused event is in progress, in which the sliding and dissipation pad (4), the anchoring plate (2) and the strike plate (3) are offset from one another, to dissipate the kinetic energy of the natural phenomenon or of the human-caused event, transmitted to the elevated structure. In detail, at least said anchoring plate (2) and/or said strike plate (3) have an outer face (2a, 3a), in contact with said sliding and dissipation pad (4), entirely coated with a soft laminar protective layer (5) which is made of dry lubrication polymeric material, with low friction coefficient and low wear and which spontaneously, stably and immovably adheres to the outer face (2a, 3a) of the anchoring plate (2) and/or of the strike plate (3).