Bicycle Frame Profiles Optimized for Drag and Stiffness
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Solution Overview
Problem
Existing bicycle structures are suboptimal in design parameters, leading to inefficiencies in performance, particularly in aerodynamics and stiffness, which affect speed and weight.
Innovation Solution
The design of bicycle frames and components with specific cross-sectional profiles optimized for aspect ratio, circumference, drag coefficient, and area moment of inertia, using equations to define parameters such as U=37.234×AR+29.67 mm for circumference and Cd=1.0627×AR−1.087 for drag coefficient, with a maximum lateral width of 20 mm and wall thickness of 1.25 mm, to enhance aerodynamics and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bicycle frame components use conventional cross-sectional structures, then manufacturing is simpler, but aerodynamic performance and stiffness are suboptimal
Solution Approach 1:
The patent applies parameter changes by optimizing specific geometric parameters of the cross-sectional profiles including aspect ratio (AR), circumference (U), drag coefficient (Cd), and area moment of inertia (Ixx). Mathematical relationships are established between these parameters (e.g., U=37.234×AR+29.67 mm, Cd=1.0627×AR−1.087) to achieve optimal stiffness and aerodynamic performance simultaneously
Solution Approach 2:
The patent employs composite material structures by combining different materials with specific properties to create frame members that achieve both high stiffness and low weight. The cross-sectional profiles are designed to work with composite materials to optimize structural performance while maintaining aerodynamic efficiency
2Productivity
If bicycle frame components are designed with optimized cross-sectional profiles, then aerodynamic performance and stiffness improve, but manufacturing precision requirements increase
Solution Approach 1:
The patent establishes mathematical relationships and tolerance ranges for critical parameters (circumference within +/−10% of calculated value, drag coefficient within +/−15% of calculated value, area moment of inertia within +/−20% of calculated value) to balance performance optimization with manufacturing feasibility
Solution Approach 2:
The patent applies partial optimization by focusing precision requirements on the most critical parameters (aspect ratio, circumference, drag coefficient, area moment of inertia) while allowing less critical dimensions to have broader tolerances, thereby achieving performance goals without requiring extreme precision across all dimensions
3Strength
If bicycle frame members use larger cross-sectional areas, then stiffness increases, but weight and drag increase
Solution Approach 1:
The patent uses composite materials with high strength-to-weight ratios to achieve increased stiffness without proportionally increasing weight. The optimized cross-sectional profiles are specifically designed to work with composite material layups to maximize structural efficiency
Solution Approach 2:
The patent applies local quality by varying the cross-sectional profile characteristics at different locations along the frame members. The aspect ratio, circumference, and area moment of inertia are optimized locally based on the specific structural and aerodynamic requirements of each frame section, allowing stiffness enhancement only where necessary
4Object-affected harmful factors
If bicycle frame components have streamlined cross-sectional profiles, then drag coefficient decreases, but structural integrity may be compromised
Solution Approach 1:
The patent establishes mathematical relationships between aerodynamic parameters (drag coefficient Cd=1.0627×AR−1.087) and structural parameters (area moment of inertia Ixx=2472.8×AR+1541.6 mm4) as functions of aspect ratio, ensuring that aerodynamic optimization does not compromise structural integrity
Solution Approach 2:
The patent employs composite material structures that allow for streamlined cross-sectional profiles while maintaining structural integrity. The composite construction provides high strength-to-weight ratio and can be tailored to distribute stresses effectively in the optimized aerodynamic shape
Data Source
AI summary
A bicycle includes a frame having cross sectional profiles. The profiles are designed according to certain criteria to enhance bicycle performance. The profiles for multiple frame members may each fall within a range for each of aspect ratio, circumference, drag coefficient, first moment of inertia and/or second moment of inertia.