Hybrid Metallic-Composite Joint Fitting for Bending Load Transfer
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Solution Overview
Problem
Aircraft landing gear systems face challenges in efficiently transmitting structural loads between metallic and composite components, requiring an optimized load path to manage axial, compressive, shear, bending, and torsional loads while minimizing weight and ensuring reliable connectivity.
Innovation Solution
A metallic-composite joint fitting featuring a frustoconical internal bearing, integral internal bolt, and conical sleeve with a flanged portion, which allows for optimized load distribution through threaded and non-threaded surfaces, ensuring effective transmission of loads and preventing relative motion between components under bending loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a composite tube is used to interface between metallic structures, then component weight is reduced, but load transmission efficiency deteriorates
Solution Approach 1:
The patent employs a hybrid metallic-composite joint fitting where a metallic end fitting with frustoconical internal bearing interfaces with a composite tube. The metallic bearing portion provides high strength load transmission while the composite tube maintains weight reduction benefits, resolving the contradiction between weight reduction and load transmission efficiency.
Solution Approach 2:
The frustoconical internal bearing acts as an intermediary component between the metallic end fitting and composite tube. It features a metallic bearing portion for load transmission and a composite outer portion for weight reduction, mediating the interface between dissimilar materials to achieve both weight reduction and efficient load transmission.
2Strength
If a connector with optimized load path is used, then load transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The joint fitting merges multiple functions into a single integrated component: the frustoconical internal bearing combines load transmission, alignment, and connection functions. The metallic end fitting integrates the bearing, bolt, and coupling features, reducing the number of separate components while maintaining optimized load paths.
Solution Approach 2:
The joint fitting is designed as a universal connector that handles multiple load types (axial, shear, bending, torsional) through its frustoconical bearing geometry and integrated metallic-composite construction, eliminating the need for separate specialized connectors for different load conditions.
3Strength
If radial contact is minimized in the joint fitting, then bending load performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The frustoconical internal bearing employs curved conical surfaces instead of flat surfaces. The conical geometry provides point or line contact rather than surface contact, minimizing radial contact area and allowing the joint to accommodate misalignment and bending loads while reducing sensitivity to manufacturing precision variations.
Data Source
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AI summary
A metallic-composite joint fitting (200) is provided. The fitting may comprise a frustoconical internal bearing (208) having a bore (222), a conical sleeve (236) configured to be disposed about the frustoconical internal bearing, a composite structure (204) configured to couple between the frustoconical internal bearing and the conical sleeve, a metallic end fitting (202) configured to be disposed within the bore and couple to the frustoconical internal bearing, and an external nut (220) configured to couple to the metallic end fitting and the conical sleeve, wherein at least one of the frustoconical internal bearing or the conical sleeve comprises a flanged portion (237) mutually configured to couple the conical sleeve to the frustoconical internal bearing via a locking ring (239).