Shape Memory Alloy Flange Connector for Re-Tensioning Double Tee Beams
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Solution Overview
Problem
Current connectors for double tee beams are prone to premature distress and deterioration, leading to reduced service life, and existing repair methods are complex and may not fully restore the joint's original strength.
Innovation Solution
A connector using a curved bolt made of shape memory alloy, which can be pre-strained and heated to apply post-tensioning, allowing for reapplication of tensioning force and self-correction under loading, utilizing super elastic properties for enhanced durability and ease of installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal connectors and hardware are used for joining double tee beam flanges, then the connection can be initially formed, but the joint is prone to premature distress and deterioration, reducing service life
Solution Approach 1:
The patent changes the material parameter from traditional metal to shape memory alloy, which fundamentally alters the connector's behavior. The shape memory alloy bolt can be deformed at lower temperatures and then recovered its original shape when heated, providing self-tensioning capability that traditional metals cannot achieve, thereby eliminating premature distress and extending service life
Solution Approach 2:
The patent utilizes the phase transition property of shape memory alloys. The bolt is deformed in the martensite phase (low temperature, easy to deform) and then heated to transform to the austenite phase (high temperature, recovers original shape), generating self-tensioning force. This phase transition mechanism provides automatic self-correction and eliminates the need for complex repair methods
2Ease of repair
If complex repair methods such as reinstatement of connection or added support are used, then damaged joints can be addressed, but the repair process is complicated and may not fully restore original strength
Solution Approach 1:
The shape memory alloy bolt provides self-service functionality through its ability to self-tension when heated. If a joint becomes loose or damaged, simply heating the bolt with a heat source (torch, heater, etc.) causes it to recover its original shape and re-tension the connection, restoring the joint to its original strength without requiring complex repair procedures
Solution Approach 2:
The patent replaces complex mechanical repair systems (reinstatement procedures, added supports, multiple components) with a simple thermal activation system. The shape memory alloy's inherent properties eliminate the need for complex repair machinery or procedures, allowing repair through simple heating that triggers the material's self-recovery mechanism
3Adaptability or versatility
If traditional connectors are used, then initial connection can be made, but reapplication of post-tensioning following degradation is not possible
Solution Approach 1:
The shape memory alloy bolt enables periodic reapplication of post-tensioning throughout the connection's lifecycle. When degradation occurs or loading conditions change, the bolt can be heated to recover its tensioning force, providing periodic maintenance capability that extends the connection lifecycle. This periodic thermal activation allows the connector to adapt to changing conditions over time
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 shape memory alloy bolt provides a durable, non-corroding solution for easily installing and maintaining connections between double tee beams, enabling effective reapplication of post-tensioning and self-correction of joint movement, thus extending the service life and simplifying repairs.
Implementation Method 1
The bolt is formed with a shape memory alloy, and in one particular embodiment, a super elastic shape memory alloy... heating the bolt to a temperature that is near or greater than the upper transition temperature of the shape memory alloy to apply post-tensioning to the joint
Implementation Method 2
The bolt is formed with a shape memory alloy, and in one particular embodiment, a super elastic shape memory alloy... pre-straining the curved bolt prior to inserting the bolt within the ducts
Data Source
AI summary
A connector for joining concrete structures such as double tee beams to one another. The connector includes a curved bolt that is formed with a shape memory alloy. Through utilization of the bolt, a joint can be post-tensioned following assembly through application of heat to the joint. Post-tensioning can be reapplied following loosening of the joint through application of heat. When considering a super elastic shape memory alloy, the bolt can be a smart bolt that can self-correct following deformation due to excessive load.