Metallic-Composite Joint Fitting With Conical Bearing Load Path
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Solution Overview
Problem
Aircraft retractable landing gear systems face challenges in efficiently transmitting structural loads between metallic and composite components, as existing solutions do not effectively optimize the load path, leading to potential weight and performance issues under axial, compressive, shear, bending, and torsional loads.
Innovation Solution
A metallic-composite joint fitting is designed with a conical end portion flared over a frustoconical internal bearing, featuring an integral internal bolt and externally threaded surface, coupled with a conical sleeve and end washer, to optimize load transmission through non-threaded surfaces for improved bending load performance and weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite tubes are used to interface between metallic structures, then component weight is reduced, but load path optimization between metallic structures and composite structure is insufficient
Solution Approach 1:
A conical composite structure serves as an intermediary element between metallic end fittings, providing optimized load path transmission. The conical geometry and composite material properties enable efficient force distribution while maintaining weight reduction benefits
Solution Approach 2:
The load path is optimized by changing the geometric parameters of the composite structure, specifically using a conical configuration with specific flare angles. This geometric parameter optimization enables improved load distribution characteristics compared to cylindrical configurations
2Ease of manufacture
If conventional fittings are used for metallic-composite joints, then manufacturing is simplified, but bending load performance is insufficient
Solution Approach 1:
The conical configuration with curved surfaces replaces conventional cylindrical or flat fittings. The curved geometry provides superior bending load performance by distributing stresses more evenly, while remaining compatible with standard manufacturing processes for composite structures
3Strength
If load paths are not optimized in metallic-composite joints, then structural integrity is maintained, but weight reduction potential is lost
Solution Approach 1:
Optimal load path transmission is achieved by carefully selecting geometric parameters including conical angle, length ratios, and interface dimensions. These parameter optimizations enable the composite structure to carry loads efficiently while minimizing material usage and overall weight
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), an internal bolt (230) coupled within a bore (222) of the frustoconical internal bearing, a metallic end fitting (202) coupled to the internal bolt, wherein the metallic end fitting comprises a bearing portion (218) disposed within the bore, a conical sleeve (236) disposed about the frustoconical internal bearing, and an external nut (220) coupled to the metallic end fitting and the conical sleeve.