Aircraft Support Structure Hole Orientation for Load-Bearing Efficiency
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Solution Overview
Problem
Existing aircraft wingbox structures with rounded access holes are inefficient in bearing external loads due to alignment issues between the holes' major axes and the principal loading direction, leading to potential weight inefficiencies and interference from nearby components.
Innovation Solution
Orienting the major axes of rounded holes in the structural member to align with the principal loading direction, allowing for efficient load bearing while minimizing weight and stress concentration, using shapes such as ellipses, Grodzinski-profiled holes, ovals, and rounded rectangles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rounded holes are oriented with major axes aligned with the longitudinal axis of the structural member, then manufacturing and maintenance access are simplified, but load bearing efficiency deteriorates when principal loading direction is not parallel to the longitudinal axis
Solution Approach 1:
The patent applies local quality by orienting each rounded hole's major axis to align with the principal loading direction specific to its location, rather than using a uniform orientation. This allows each hole to be optimally positioned for its local stress conditions while maintaining the structural integrity required for load bearing.
Solution Approach 2:
The patent changes the orientation parameter of the rounded holes from a fixed alignment with the longitudinal axis to variable alignment with the principal loading direction. This parameter change allows the structure to adapt to different loading scenarios and improves overall load bearing efficiency.
2Ease of operation
If more rounded holes are added to the structural member, then access for maintenance and passage for lines is improved, but stress concentration and structural weakness increase
Solution Approach 1:
The patent applies local quality by strategically positioning rounded holes in areas where they provide necessary access while minimizing disruption to high-stress regions. Each hole's location and orientation are optimized for its specific function, allowing adequate maintenance access without compromising overall structural integrity.
Solution Approach 2:
The patent uses rounded holes with curved boundaries instead of sharp corners, which reduces stress concentration at the hole edges. The elliptical or rounded rectangular shapes with curved transitions help distribute stress more evenly around the hole perimeters, maintaining structural strength while providing necessary access.
3Strength
If rounded holes are oriented at various angles to accommodate different loading directions, then load bearing efficiency improves, but manufacturing complexity and precision requirements increase
Solution Approach 1:
The patent changes the orientation parameter of rounded holes from fixed to variable based on principal loading directions. By allowing holes to be oriented at different angles matching the local principal stress directions, the structure achieves optimal load bearing efficiency while the parameter variation is systematically managed.
Solution Approach 2:
The patent segments the structural member into regions with different principal loading directions, with each region having rounded holes oriented accordingly. This segmentation allows each local region to be optimized independently for its specific loading conditions while maintaining overall structural coherence.
Data Source
AI summary
A support structure for an aircraft includes a structural member having a generally planar shape, a longitudinal axis defining a longitudinal direction and a transverse axis orthogonal to the longitudinal axis, and a plurality of rounded holes formed along the longitudinal direction. Each rounded hole has a respective major axis with a major length and a minor axis orthogonal to the major axis with a minor length that is less than the major length. Each rounded hole is oriented with its major axis rotated more than 0 degrees and less than 90 degrees from the longitudinal axis of the structural member. The structural member is configured for bearing external loads acting on the structural member in a principal loading direction that is not parallel with the longitudinal axis or the transverse axis. Each rounded hole may be oriented with its major axis aligned generally parallel with the principal loading direction.