Superelastic Racket String Phase Transition Stiffness Control
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Solution Overview
Problem
Conventional ball game racket strings fail to meet the complex mechanical property requirements of high specific strength, low stiffness, and high elongation at break, with existing materials not fully addressing these needs.
Innovation Solution
Employing a superelastic or pseudoelastic material, such as Nitinol, for the strings, which allows for adjustable tensile stiffness through phase transitions between austenite and martensite, enabling reduced string diameter with enhanced strength and deformation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional materials (natural gut or polyester) are used for racket strings, then the strings have sufficient elasticity and tension stability, but the tensile strength is limited and the diameter must be larger to achieve required breaking strength
Solution Approach 1:
The patent changes the material parameter from conventional natural gut or polyester to superelastic material (such as nitinol), which fundamentally alters the stress-strain relationship and enables much higher tensile strength at smaller diameters
Solution Approach 2:
The patent employs composite construction by combining superelastic material properties with specific phase transition characteristics (austenite-martensite transformation) to create a string material that achieves both high strength and low diameter
2Object-affected harmful factors
If the string diameter is reduced to improve aerodynamics, then the aerodynamic performance improves, but the tensile strength decreases
Solution Approach 1:
The patent changes the material parameters to superelastic material properties, which provide such high tensile strength that the diameter can be reduced by approximately half compared to natural gut strings while maintaining or exceeding required strength levels
Solution Approach 2:
The patent applies different material properties locally by utilizing the phase transition characteristics of superelastic materials, where the material exhibits different stiffness and strength properties depending on the phase state, allowing optimization for both strength and aerodynamics
3Strength
If superelastic material is used for the string, then the tensile strength increases significantly and diameter can be reduced, but the tensile stiffness becomes difficult to control
Solution Approach 1:
The patent applies dynamic control by utilizing the phase transition between austenite and martensite states, which allows the tensile stiffness to be dynamically adjusted based on the applied load and temperature conditions
Solution Approach 2:
The patent exploits the phase transition phenomenon of superelastic materials, where the austenite-martensite transformation provides a mechanism to control tensile stiffness independently of tensile strength, allowing the string to exhibit appropriate stiffness characteristics during normal use
4Stability of the object's composition
If natural gut strings are used, then high elasticity and tension stability are achieved, but the cost is very high and sensitivity to weather conditions increases
Solution Approach 1:
The patent replaces expensive natural gut material with more affordable superelastic materials such as nitinol, which provide comparable or superior performance while being less sensitive to weather conditions and more cost-effective
Solution Approach 2:
The patent changes the material composition from organic natural gut to inorganic superelastic alloy, fundamentally altering the material's response to environmental factors and eliminating weather sensitivity while maintaining tension stability
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 use of superelastic materials like Nitinol provides strings with higher tensile strength, adjustable stiffness, and increased elongation at break, improving playing behavior by reducing string diameter while maintaining strength and control, allowing for extreme deformations and enhanced control during gameplay.
Implementation Method 1
their tensile stiffness can be significantly influenced by the phase transition between austenite and martensite
Implementation Method 2
a string for a ball game racket which consists of or comprises a superelastic or pseudoelastic material
Data Source
Figure 1~2
AI summary
The present invention relates to a ball-game racket comprising a stringing that has at least one string including a superelastic material.