Integral Composite Spar-Cover Recess Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration of spar and cover panels in aircraft wing boxes, especially with composite materials, faces challenges due to manufacturing tolerances and variability, requiring precise tooling and costly thickness control measures, which are exacerbated by the extensive length of commercial aircraft wings.
Innovation Solution
An aircraft assembly with an integral spar-cover formed from composite laminate material, featuring a recess at the fold region between the spar and cover, allowing for flexibility and decoupling of end regions, reducing the need for shimming and thickness control, and reinforced with a bridging element to maintain load-carrying ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spar and cover are integrally formed from composite laminate material, then the mechanical performance and structural integrity are improved, but the manufacturing precision requirements worsen due to cumulative tolerance variations over the extensive wing length
Solution Approach 1:
The integral spar-cover is divided into two functional zones: a fold region where the composite material continuously transitions from spar to cover, and a recess region that separates the spar end region from the cover end region. This segmentation allows the continuous composite structure to maintain its mechanical advantages while the recess provides a localized discontinuity that accommodates tolerance variations and enables independent positioning of the spar and cover at the wing tip.
2Manufacturing precision
If strict manufacturing tolerances are enforced to ensure close fitting of components at the outboard end, then the assembly precision is improved, but the device complexity and cost increase due to expensive thickness control measures and accurate tooling requirements
Solution Approach 1:
The recess modifies the geometric parameters of the spar-cover structure by creating a localized discontinuity in the fold region. This parameter change introduces flexibility into the otherwise rigid integral structure, allowing the spar end region and cover end region to be positioned independently at the wing tip, thereby accommodating tolerance variations without requiring expensive thickness control measures.
3Ease of manufacture
If the spar and cover are assembled as separate components, then the manufacturing flexibility is improved, but the structural integrity and mechanical performance deteriorate compared to an integral structure
Solution Approach 1:
The spar and cover are merged into a single integral spar-cover component manufactured from continuous composite laminate material. The fold region creates a continuous material path that provides superior structural integrity and mechanical performance compared to assembled components, while the recess introduces a controlled discontinuity that retains some manufacturing flexibility for tolerance accommodation.
Data Source
AI summary
An aircraft assembly is disclosed including a longitudinal spar and an aerofoil cover integrally formed from a composite laminate material to form a spar-cover such that the composite material of the spar extends continuously into the cover through a fold region created between the spar and the cover. The spar and cover are separated by a recess at a longitudinal end of the fold region to define a spar end region and a cover end region, and a reinforcement element extends between the spar end region and the cover end region to couple the spar end region with the cover end region.