Multi-Segment Aircraft Spar Assembly for Complex Curvature Fabrication
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Solution Overview
Problem
The fabrication of aircraft spars, particularly those with complex curvatures, is complicated by their large dimensions, which increase the complexity and expense of equipment and processes such as layup, consolidation, and hardening, especially when multiple spars are involved.
Innovation Solution
The method involves fabricating aircraft spars from multiple segments that are structurally integrated via co-curing, co-bonding, or fastener installation, allowing for simpler curvature profiles and reduced equipment size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spars are fabricated as single large components, then structural strength is improved, but fabrication complexity and equipment requirements increase
Solution Approach 1:
The spar is divided into multiple segments that can be fabricated separately using smaller, less complex equipment. Each segment maintains structural integrity while the overall spar achieves full strength through precise joining of segments at designated splice locations
Solution Approach 2:
Splice doublers are pre-installed at designated locations on each segment before final assembly. This preliminary action ensures proper alignment and structural continuity when segments are joined, maintaining the strength equivalent to a monolithic spar
2Stability of the object's composition
If spars are fabricated as single large components, then structural integrity is improved, but equipment size and cost increase
Solution Approach 1:
The spar is segmented into smaller sections that can be manufactured using compact equipment. The segments are then joined using splice doublers that restore structural integrity, achieving full spar strength without requiring oversized fabrication equipment
Solution Approach 2:
Instead of joining segments end-to-end in a single linear sequence, splice doublers are installed at multiple locations along the spar length, allowing parallel assembly operations and reducing the effective equipment workspace required
3Productivity
If multiple spars are fabricated simultaneously, then productivity is improved, but space requirements and process complexity increase
Solution Approach 1:
Multiple spars are divided into segments that can be fabricated in parallel on smaller fixtures. The segments from different spars can be assembled simultaneously, increasing throughput without requiring proportionally larger fabrication space
Solution Approach 2:
The fabrication process merges segment preparation and splice doubler installation into integrated operations. Multiple segments can be worked on simultaneously using shared tooling and fixtures, improving productivity while optimizing space utilization
4Adaptability or versatility
If spars with complex curvatures are fabricated, then design flexibility is improved, but fabrication difficulty increases
Solution Approach 1:
Complex curvature profiles are divided into smaller segments, each with simpler local geometry. This allows standard fixtures and tools to be used for each segment while the overall curved shape is achieved through precise positioning and joining of segments
Solution Approach 2:
Each spar segment is designed with local quality variations optimized for its specific position in the curved spar. Splice doublers are strategically placed at locations where curvature changes, providing localized reinforcement without complicating the entire fabrication process
Data Source
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AI summary
Systems and methods are provided for fabricating multiple segment spars for an aircraft. In one example the method includes fabricating preforms of fiber reinforced material for spar segments, hardening the preforms to form the spar segments, and bonding the spar segments together to form a completed spar detail. In addition to bonding, other examples include co-curing and fastening the spar segments. In additional examples, the spar segments include kinks or sub-kinks as described.