Covered Shape-Memory Fibers That Limit Overstretching
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Solution Overview
Problem
Conventional shape-memory polymeric fibers lose their shape-memory functionality when stretched beyond their recoverable range, leading to reduced shape recovery ratio and fixity, limiting their usability in dynamic environments like medical, orthopedic, leisure, and sports applications.
Innovation Solution
A covered shape-memory polymeric fiber design, where a substantially unstretchable covering yarn is wound around the core fiber to limit its maximum engineering strain to the yield point, ensuring consistent shape fixity and recovery across multiple cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional polymeric fibers are used, then textile processing is straightforward, but the fibers lack shape memory capability and functional responsiveness
Solution Approach 1:
The patent applies composite materials by combining polymeric fibers with metal wires or fibers to create a composite structure. The polymeric fiber provides flexibility and texturizing properties, while the metal component provides shape memory capability. This composite approach enables the fiber to exhibit shape memory functionality without requiring the entire fiber structure to be complex, thus resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The patent applies local quality by incorporating shape memory materials only in specific regions or layers of the textile composite structure. Rather than making the entire fiber structure complex, the shape memory capability is localized to specific portions that require it, while other portions maintain simple, conventional fiber properties. This allows shape memory functionality to be added with minimal increase in overall structural complexity.
2Adaptability or versatility
If shape memory materials are incorporated, then functional responsiveness is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the textile structure into separate layers or components, with shape memory materials incorporated only in specific segments rather than throughout the entire structure. This allows the shape memory functionality to be integrated in a controlled manner during manufacturing, maintaining relative simplicity in the overall manufacturing process while achieving functional responsiveness in the required areas.
Solution Approach 2:
The patent applies preliminary action by pre-forming and pre-coating the shape memory materials onto the polymeric fibers before final textile assembly. This preliminary incorporation of shape memory materials simplifies subsequent manufacturing steps, as the functional components are already in place and require only integration into the final textile structure rather than complex in-line processing.
3Shape
If metal wires are covered with polymeric fibers, then aesthetic appearance is improved, but the shape memory function may be compromised
Solution Approach 1:
The patent applies flexible shells and thin films by using thin polymeric fiber coatings or sheaths that cover the metal wires or fibers. These thin film structures provide the necessary aesthetic appearance and texturizing properties while maintaining sufficient flexibility and thermal conductivity for the shape memory function to operate reliably. The thin film thickness is carefully controlled to balance aesthetic requirements with functional performance.
Solution Approach 2:
The patent applies parameter changes by carefully controlling the thermal and mechanical parameters of the polymeric coating layers. The coating is designed with specific thermal conductivity, thickness, and mechanical properties that allow heat to reach the shape memory material effectively while maintaining aesthetic appearance. By optimizing these parameters, the patent ensures that the shape memory function remains reliable despite the covering 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 design maintains high shape recovery ratios and durability by preventing overstretching, making it suitable for a wider range of applications, particularly in medical textiles requiring controlled compression and consistent support.
Implementation Method 1
the fiber is capable of undergoing a phase transition in response to a change in temperature
Implementation Method 2
the fiber is capable of undergoing a phase transition in response to a change in temperature or undergoes viscoelastic deformation in response to an applied force
Data Source
Figure 1~2B
Figure 3A~3B
Figure 4A~4B
AI summary
The present invention relates to the field of textiles, in particular shape-memory polymeric fibers (SMPF) for textile applications or medical applications where shape fixity and recovery can be kept constant over multiple shape-memory cycles. The present invention relates to a covered shape-memory polymeric fiber (cSMPF) (1) having a core fiber (10) comprising a shape-memory polymer fiber and a substantially unstretchable covering yarn (20) wound around the core fiber (10) in a manner that the maximum engineering strain (εmax) of the core shape-memory fiber is reduced to at most the strain at the yield point (εyield) of the uncovered core fiber (10) thus limiting the stretchability or deformation of the core shape-memory fibers and/or textiles and/or fabrics comprising a covered shape-memory fiber during programming or use so as to ensure maximum recoverable strain. Also disclosed is a process for producing a covered shape-memory polymeric fiber (cSMPF) (1), a shape-memory fiber and a shape-memory textile comprising a covered shape-memory polymeric fiber (cSMPF).