Composite Structural Member with Variable Fiber Orientation
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Solution Overview
Problem
Composite structural members with fiber reinforcement face challenges in optimizing fiber orientation to balance shear resistance and longitudinal force transmission, leading to reduced rigidity and increased stress, which is particularly significant in mass-critical applications like aeronautics.
Innovation Solution
A composite structural member with layers oriented at 0°, 90°, and ±θ, with variable proportions along the transverse direction to adapt rigidity to mechanical stresses, and a wing box spar design with varying fiber orientations to optimize force transmission and reduce mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fibers are oriented at +/−45° to maximize shear resistance, then shear strength is improved, but longitudinal rigidity deteriorates
Solution Approach 1:
The patent applies different fiber orientation configurations to different regions of the composite member. The extremity areas have a higher proportion of 0° fibers for longitudinal rigidity, while central areas have more +/−45° fibers for shear resistance. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirements rather than using a uniform orientation throughout.
Solution Approach 2:
The composite member is divided into distinct functional zones: extremity areas and central areas, each with different fiber orientation compositions. This segmentation allows the structure to simultaneously optimize for both longitudinal rigidity (in extremities) and shear resistance (in central areas), resolving the global contradiction through spatial differentiation.
2Strength
If fiber orientation is optimized for shear resistance, then shear strength is improved, but overall rigidity deteriorates
Solution Approach 1:
Different regions of the member are assigned different fiber orientation mixes tailored to their specific stress patterns. Extremity areas use more 0° fibers for rigidity where longitudinal loads are critical, while central areas use more +/−45° fibers for shear resistance where transverse loads dominate. This local optimization ensures overall rigidity is maintained while shear strength is maximized.
3Stress or pressure
If reduced rigidity increases stress, then stress distribution is improved, but mass increases due to oversizing
Solution Approach 1:
The patent optimizes fiber orientation locally to match the stress distribution pattern. Areas with higher stress concentration (extremities) receive more 0° fibers for enhanced rigidity, while lower stress areas (central region) use more +/−45° fibers. This targeted approach allows stress to be distributed efficiently without requiring excessive mass throughout the entire structure.
Data Source
AI summary
A composite structural member with fiber reinforcement comprising a plurality of layers oriented relative to a longitudinal direction of said member in directions including 0°, 90° and +/−θ, the relative proportion of layers in one of these orientations being variable along a transverse direction of said member so as to spatially adjust the rigidity of the member according to a defined distribution of mechanical stresses along this transverse axis. The rigidity of the member is adapted locally to the stress system so as to dissipate the force flux over the entire volume of said member.