Gas Turbine Duct Ball Joint With Localized Thickening
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Solution Overview
Problem
Current ball joints in gas turbine engines face issues with increased weight, compromised dynamic performance, and stress concentration due to non-optimized thicknesses and material limitations, which affect bending moment and axial stiffness.
Innovation Solution
A ball joint configuration with localized thickenings on the inner and outer shrouds, combined with 3D printing, to enhance mechanical properties, reduce stress levels, and improve axial stiffness while maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If current ball joint configuration with quasi-constant thickness is used, then manufacturing is simplified, but weight increases and mechanical properties deteriorate
Solution Approach 1:
The patent applies local quality by transitioning from a quasi-constant thickness design to an optimized variable thickness distribution. The thickness of the ball joint shell is specifically varied in different regions to match the actual stress distribution, providing greater thickness where stresses are higher and reducing thickness where stresses are lower, thereby optimizing the weight-strength trade-off.
2Ease of manufacture
If current ball joint configuration with quasi-constant thickness is used, then manufacturing is simplified, but bending moment and axial stiffness deteriorate
Solution Approach 1:
The optimized variable thickness distribution is designed to specifically enhance axial stiffness and bending moment resistance. By concentrating material in regions experiencing higher axial and bending loads, the design improves these mechanical properties while maintaining manufacturability through a systematic thickness variation approach.
3Strength
If large thicknesses are used to support loads, then strength is improved, but weight increases and stress concentrators are required
Solution Approach 1:
The patent eliminates the need for stress concentrators by implementing a smoothly varying thickness distribution that naturally accommodates stress flow. This optimized variable thickness design provides the necessary load support capability through strategic material placement rather than through stress concentration features, thereby reducing weight while maintaining strength.
4Ease of manufacture
If materials compatible with forming process are used, then manufacturing is simplified, but material selection is limited and mechanical properties are compromised
Solution Approach 1:
The patent employs advanced manufacturing techniques such as additive manufacturing or precision casting that enable the production of complex variable thickness geometries. These parameter-changing manufacturing approaches expand material selection flexibility beyond traditional forming process limitations while maintaining manufacturing feasibility through modern fabrication capabilities.
Data Source
AI summary
A ball joint connecting first and second tubular portions of a gas turbine engine duct assembly, accommodating angular variations between their longitudinal axes while resisting axial forces. The ball joint includes a housing with inner and outer shrouds that partially overlap to form an interface, and an internal bellows with limited flexure capability. The inner shroud extends from the first tubular portion and features a first thickening and spherical portion, while the outer shroud extends from the second tubular portion and includes a spherical portion and second thickening. During rest conditions, the overlapping interface between shrouds remains annularly constant, but under flexure stresses, this interface varies annularly while maintaining overlap. This design enables controlled angular movement within predetermined limits while providing structural integrity for gas turbine engine duct connections.