Aircraft Pi Preform Joints for Weight Reduction
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Solution Overview
Problem
Designing bonded pi structure joints for aircraft components is challenging due to the sensitivity of assembly structure changes, making it difficult to achieve weight reduction and cost efficiency.
Innovation Solution
A support structure for aircraft components comprising spars and ribs with overlapping first, second, and third pi elements, formed from carbon fiber or epoxy preforms, which secure the skins in a lightweight and durable manner, enhancing rigidity and wear resistance while allowing for efficient assembly and fuel-tight sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If bonded pi structure joints are used to decrease weight and cost, then weight reduction is achieved, but assembly structure sensitivity increases making design challenging
Solution Approach 1:
The patent divides the bonding structure into multiple discrete pi elements (first pis, second pis, third pis) with specific overlapping arrangements. Each pi element serves a distinct bonding function between different structural components (skins, spars, ribs), allowing the complex assembly to be managed through standardized modular units rather than monolithic bonding structures.
Solution Approach 2:
The pi elements are pre-configured with specific overlap lengths and bonding patterns before final assembly. The overlapping regions are designed in advance to ensure proper alignment and load distribution, reducing the sensitivity to assembly variations and making the bonding process more predictable and less challenging.
2Adaptability or versatility
If small revisions are made to bonded pi structure, then adaptability is improved, but assembly structure stability deteriorates
Solution Approach 1:
Different pi elements have different overlap characteristics and bonding configurations tailored to their specific locations and functions. The first pis, second pis, and third pis each have optimized overlap lengths and bonding patterns suited to their local structural requirements, allowing localized adaptations without compromising the overall assembly stability.
Solution Approach 2:
Multiple pi elements are combined in an overlapping arrangement where their bonding regions intersect and reinforce each other. This merging of bonding functions creates a synergistic effect where the combined structure is more stable than individual elements, allowing design flexibility while maintaining overall structural integrity.
3Strength
If overlapping pi elements are used to secure skins, then bonding strength is improved, but manufacturing complexity increases
Solution Approach 1:
The bonding solution extends into the dimensional space of overlapping layers rather than relying solely on single-plane bonding. The pi elements are arranged in multiple layers with specific overlap lengths, creating a three-dimensional bonding network that increases strength through distributed load paths while maintaining manufacturability through standardized layer configurations.
Data Source
AI summary
A support structure for reinforcing first and second skins in an aircraft component includes a plurality of spars. A plurality of ribs is positioned on opposite sides of the spars. Each rib has a height extending from adjacent the first skin to adjacent the second skin. A plurality of first pis connects the ribs to the spars with each first pi having a length. A plurality of second pis secures the spars to the first and second skins. A plurality of third pis secures the ribs to the first and second skins. The first pis overlap with at least one of the second pis or the third pis.