Metallic-Composite Joint Fitting With Internal Bearing Load Path
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Solution Overview
Problem
Aircraft landing gear systems face challenges in efficiently transmitting structural loads between metallic and composite components, particularly in distributing axial, compressive, shear, bending, and torsional loads effectively while minimizing weight and ensuring reliable connections.
Innovation Solution
A metallic-composite joint fitting featuring a frustoconical internal bearing, a conical sleeve, a composite structure, and a metallic end fitting, along with an external nut and locking ring, which optimizes load paths through threaded and non-threaded surfaces to enhance load distribution and prevent relative motion between components.
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 efficient transmission of structural loads becomes challenging
Solution Approach 1:
A metallic bearing is introduced as an intermediary component between the composite tube and metallic end fitting. The bearing provides a dedicated load transmission path that efficiently transfers axial, compressive, shear, bending, and torsional loads between the composite and metallic structures, resolving the contradiction by maintaining reliability while preserving weight benefits.
Solution Approach 2:
The solution employs a hybrid metallic-composite construction where a metallic bearing is integrated with composite tube sections. This composite approach allows each material to perform its optimal function: the metallic bearing handles load transmission while the composite tube provides weight reduction, achieving both lightness and structural reliability.
2Productivity
If working loads are transmitted directly through the composite structure, then an optimized load path is achieved, but bending load transmission through threaded surfaces increases
Solution Approach 1:
The load transmission path is segmented into distinct functional zones: the metallic bearing handles axial and compressive loads through its bore, while the conical sleeve and flanged portions specifically address bending loads. This segmentation prevents bending loads from being transmitted through threaded surfaces, preserving strength while maintaining optimized load paths.
Solution Approach 2:
The bearing function is extracted from the threaded connection system and placed into a dedicated metallic bearing component. By removing the bearing function from the threaded interface, bending loads are prevented from traveling through the threaded surfaces, thereby protecting the threaded connection while maintaining efficient load transmission through the bearing.
Data Source
AI summary
A metallic-composite joint fitting is provided. The fitting may comprise a frustoconical internal bearing having a bore, a conical sleeve configured to be disposed about the frustoconical internal bearing, a composite structure configured to couple between the frustoconical internal bearing and the conical sleeve, a metallic end fitting configured to be disposed within the bore and couple to the frustoconical internal bearing, and an external nut 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 mutually configured to couple the conical sleeve to the frustoconical internal bearing via a locking ring.