Break Resistant Composite Stringer System for Surfboards
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Solution Overview
Problem
Current surfboard stringer systems, particularly in non-fiberglass surfboards, are prone to breaking at the nose and tail due to limited extension of stringers, leading to increased risk of fracture under bending and torsional forces from wave impacts, and existing solutions like I-beam stringers are heavy, costly, and complex to manufacture.
Innovation Solution
A break-resistant composite stringer system featuring a stringer body with U-shaped fibrous channels bonded to its top and bottom surfaces, extending to the ends, made from wood or laminated bamboo, with a heat-resistant adhesive, providing enhanced stiffness and flexural strength without significant weight or manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stringer systems are used in non-fiberglass surfboards, then the surfboard can be manufactured with simpler materials and processes, but the stringers cannot extend to the ends of the nose rocker and tail rocker, making the ends more prone to breaking
Solution Approach 1:
The stringer system is divided into multiple segments: a central stringer body and separate fibrous strips that extend beyond it. These segments are bonded together to form a composite structure where the fibrous strips extend to the nose and tail rocker ends, providing enhanced break resistance at these vulnerable locations while the central stringer body provides core structural support.
Solution Approach 2:
The invention uses a composite stringer system combining a central stringer body (made of traditional materials like balsa wood or bamboo) with fibrous strips (such as fiberglass or carbon fiber). This composite structure leverages the strength and stiffness of the fibrous materials to extend protection to the nose and tail ends, while maintaining the benefits of traditional stringer materials in the central region.
2Strength
If I-beam stringers made of aluminum or fibrous materials are used to increase lateral breaking resistance, then the strength is improved, but the heavy weight and high cost make them prohibitive
Solution Approach 1:
Instead of using heavy I-beam construction throughout the entire stringer, the invention applies fibrous strips only where needed - extending from the central stringer body to the nose and tail rocker ends. This localized reinforcement provides lateral breaking resistance precisely where the board is most vulnerable, without adding unnecessary weight to the entire stringer system.
Solution Approach 2:
The invention changes the material parameters by using thin, high-strength fibrous strips rather than bulky I-beam construction. These strips provide equivalent or superior lateral breaking resistance to I-beams but with significantly reduced weight and material cost, achieving the same structural benefit through different material properties and geometry.
3Shape
If I-beam stringers are manufactured in bow shape to match surfboard curvature, then the hydrodynamic performance is improved, but the manufacture becomes unnecessarily complex and expensive
Solution Approach 1:
The bow-shaped stringer is segmented into a central stringer body and separate fibrous strips. The central body can be manufactured in the required bow shape using traditional methods, while the fibrous strips are applied as separate components that conform to the curvature. This segmentation simplifies manufacturing compared to forming a complete I-beam in bow shape, as the fibrous strips can be laid up and cured in place to match the board's curvature.
Solution Approach 2:
The fibrous strips are shaped to copy or conform to the curvature of the central stringer body and the surfboard's nose and tail rockers. Rather than manufacturing complex bow-shaped I-beams, the fibrous strips are applied to replicate the required geometry, simplifying the manufacturing process while achieving the hydrodynamic benefits of the curved shape.
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 composite stringer system significantly increases the surfboard's breaking strength and stiffness, reducing the likelihood of fracture and enhancing safety by distributing impact forces effectively, while maintaining a lightweight and cost-effective design.
Implementation Method 1
A heat resistant waterproof adhesive resin is bonded between the fibrous channels and the stringer body
Data Source
AI summary
A break resistant composite stringer system for a sports board includes an elongated stringer body. An upper U channel is fibrous and includes an upper U channel right flange and an upper U channel left flange. The upper U channel right flange is vertically oriented and the upper U channel left flange is vertically oriented. An inside surface of the upper U channel is bonded to the stringer right surface, the stringer top surface, and the stringer left surface. A lower U channel is fibrous and includes a lower U channel right flange and a lower U channel left flange. The lower U channel right flange is vertically oriented and the lower U channel left flange is vertically oriented. An inside surface of the lower U channel is bonded to the stringer right surface, the stringer bottom surface, and the stringer left surface.