Bow Limbs With Angled Fiber Sheets
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Solution Overview
Problem
Modern bow designs face challenges in maximizing potential energy input to achieve higher kinetic energy output, as existing materials and constructions limit the dynamic flexural stiffness of bow limbs.
Innovation Solution
The bow features laminated fiber-reinforced plastic upper and lower limbs with strategically angled fiber sheets, achieving a Poisson's ratio greater than 0.75, which enhances dynamic anticlastic curvature and flexural stiffness, increasing potential energy storage and kinetic energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard Poisson's ratio materials (0.3 to 0.75) are used for bow limbs, then the bow structure is simple and easy to manufacture, but the flexural stiffness and kinetic energy output are limited
Solution Approach 1:
The bow limbs are constructed using fiber-reinforced plastic composite materials with a specific lamination structure. Multiple fiber sheets are stacked and oriented at different angles (including 0°, 90°, and ±45°) to create an orthotropic material structure that achieves ultra-high Poisson's ratio (>0.75) while maintaining structural integrity and enhancing flexural stiffness.
Solution Approach 2:
The invention changes the Poisson's ratio parameter of the bow limb material from conventional values (0.3 to 0.75) to ultra-high values (>0.75) through specific fiber orientation and lamination design. This parameter change fundamentally alters the material's elastic properties, enabling enhanced dynamic flexural stiffness and anticlastic curvature during bow drawing.
2Use of energy by moving object
If fiber sheets are oriented at specific angles (16-44 degrees) to increase Poisson's ratio, then dynamic flexural stiffness and potential energy storage increase, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies fiber sheet orientation angles within a range (16-44 degrees) rather than requiring a single precise angle, allowing manufacturers to achieve the desired ultra-high Poisson's ratio effect with reasonable manufacturing tolerances while still obtaining enhanced potential energy storage capability.
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 significantly increases the bow's flexural stiffness and kinetic energy output by optimizing the fiber orientation and Poisson's ratio, surpassing the performance of prior art bows with standard Poisson's ratios between 0.3 to 0.75.
Implementation Method 1
achieving a Poisson's ratio greater than 0.75, which enhances dynamic anticlastic curvature and flexural stiffness
Implementation Method 2
enhances dynamic anticlastic curvature and flexural stiffness, increasing potential energy storage and kinetic energy transfer
Data Source
AI summary
A bow includes a handle and upper and lower limbs. The upper and lower limbs are formed of a laminated fiber-reinforced plastic material. The upper limb has first and second sets of fiber sheets stacked in a direction along a lateral axis. The first set of fiber sheets have fibers aligned at a first angle from a longitudinal axis, and the second set of fiber sheets having fibers aligned at a second angle from the longitudinal axis in an opposite direction. The lower limb has third and fourth sets of fiber sheets stacked in a direction along the lateral axis. The third set of fiber sheets have parallel fibers aligned at a third angle from the longitudinal axis, and the fourth set of fiber sheets having fibers aligned at a fourth angle from the longitudinal axis in an opposite direction. The angles are between 16 and 44 degrees.