Cold-Drawn SMA Cable Structure for Concrete Prestressing Adhesion
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Solution Overview
Problem
Existing shape memory alloy cables require large-capacity tensioning equipment and have poor adhesion to concrete, making them impractical for field applications like concrete confinement and prestressing, as they slip easily due to low adhesive force.
Innovation Solution
A cable design featuring a core wire and peripheral wires made of cold-drawn shape memory alloy, where the peripheral wires are either straight or corrugated, wound around the core wire, eliminating the need for direct tensioning and enhancing adhesion to concrete by using corrugated wires with optimized corrugation patterns for improved stress distribution and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple strands of shape memory alloy wire are directly tensioned to cause deformation, then the shape memory effect is activated, but large-capacity tensioning equipment is required and the process becomes ineffective for field applications
Solution Approach 1:
The cable is segmented into multiple individual shape memory alloy wires (typically 7 wires) bundled together. Each wire can be deformed independently during manufacturing to store elastic energy, eliminating the need for large-capacity field tensioning equipment. The segmented structure allows the cables to be handled and installed using conventional construction equipment while maintaining the shape memory effect functionality.
Solution Approach 2:
The shape memory alloy wires are deformed and tensioned in advance during the cable manufacturing process rather than in the field. This preliminary action stores elastic energy within each wire, so that when the cable is installed and heated, the pre-stored deformation activates the shape memory effect without requiring large tensioning equipment at the construction site.
2Reliability
If smooth surface shape memory alloy wires are used, then the shape memory effect is maintained, but adhesive force to concrete is insufficient causing slip and reduced recovery stress
Solution Approach 1:
The cable structure applies different surface qualities to different components: the individual shape memory alloy wires maintain smooth surfaces to preserve the shape memory effect, while the外围 concrete interaction surface is enhanced through the cable's outer configuration and bonding agents. This local differentiation allows each component to optimize its specific function without compromise.
Solution Approach 2:
The cable employs a composite structure combining multiple shape memory alloy wires bundled together, often with additional bonding materials or surface treatments. This composite approach maintains the intrinsic shape memory properties of the alloy wires while enhancing the overall adhesive force to concrete through the combined effect of multiple wires and supplementary bonding mechanisms.
3Reliability
If multiple strands of shape memory alloy wire are used, then the shape memory effect is achieved, but the equipment required is very long and complex
Solution Approach 1:
By segmenting the cable into multiple individual wires that are tensioned independently during manufacturing, the system eliminates the need for complex, large-capacity field tensioning equipment. Each wire's smaller cross-section allows for simpler handling and deformation processes that can be completed during cable production rather than requiring sophisticated field equipment.
Solution Approach 2:
The tensioning and deformation operations are performed in advance during cable manufacturing, transferring the complexity to the factory setting where controlled conditions and specialized equipment are available. This eliminates the need for complex tensioning equipment at the construction site, simplifying field operations significantly.
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 cable design allows for effective field application without large-capacity tensioning equipment and provides excellent adhesion to concrete, reducing the need for fixing devices and enabling efficient prestressing operations.
Implementation Method 1
a core wire configured by a cold-drawn shape memory alloy deformed by cold drawing to have an increased length; and a plurality of peripheral wires coupled to the core wire while being wound in a same direction along the circumference of the core wire, and configured by a cold-drawn shape memory alloy deformed by cold drawing to have an increased length
Implementation Method 2
In general, a shape memory alloy (SMA) is capable of exhibiting a shape memory effect and thus recovering from a deformation
Implementation Method 3
it is therefore impossible to practically use the same on a construction site or the like. For example, if deformation is introduced by directly tensioning a wire made of multiple strands of shape memory alloy, equipment capable of applying a large amount of tension is necessary
Data Source
AI summary
The present invention relates to a cable using cold-drawn shape memory alloy wires, which facilitates concrete prestressing or other operations, and has excellent adhesion to concrete and manufacturability. The cable using cold-drawn shape memory alloy wires includes: a core wire configured by a cold-drawn shape memory alloy deformed by cold drawing to have an increased length; and a plurality of peripheral wires configured by cold-drawn shape memory alloy wires which are deformed by cold drawing to have an increased length and are couple to the core wire while being wound in a same direction along the circumference of the core wire.