Gimbaled Flexure Joint Assembly for Thermal Growth in Bleed Air Ducts
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Solution Overview
Problem
Current systems for bleed air ducting in turbine engines face challenges in providing both rigidity under dynamic loading and flexibility under thermal loading, often compromising system dynamic performance and increasing weight due to the use of ball-joints or axial-joints.
Innovation Solution
A flex joint assembly utilizing a gimbaled joint with a bellows and gimbal ring assembly, featuring four flexure hinges and a ring and spoke configuration, provides improved rotational compliance to mitigate reaction loading and thermal growth in high-temperature bleed-air ducting systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ball-joints or axial-joints are used in the duct to provide flexibility under thermal loading, then flexibility under thermal loading is improved, but system dynamic performance deteriorates and weight increases
Solution Approach 1:
The joint assembly is segmented into multiple functional components: a bellows for thermal expansion accommodation, a gimbal ring assembly with four flexure hinges for rotational compliance, and support structures for load bearing. This segmentation allows each component to specialize in one function, maintaining dynamic performance while providing thermal flexibility.
Solution Approach 2:
The patent replaces traditional mechanical ball-joints or axial-joints with a flexure hinge-based gimbal mechanism. The flexure hinges provide rotational compliance through elastic deformation rather than mechanical joints, eliminating the need for bearings, pins, and other mechanical components that compromise dynamic performance.
2Adaptability or versatility
If ball-joints or axial-joints are used in the duct to provide flexibility under thermal loading, then flexibility under thermal loading is improved, but weight increases
Solution Approach 1:
The bellows component uses a flexible convoluted structure to accommodate thermal expansion and contraction. This flexible shell design provides the necessary thermal flexibility without requiring heavy mechanical joints, significantly reducing the overall weight of the ducting system.
Solution Approach 2:
The joint assembly utilizes composite construction combining the bellows, gimbal ring, and support structures to achieve optimal weight-to-strength ratio. The flexure hinges and gimbal mechanism are designed to provide maximum compliance with minimum mass, avoiding the weight penalty of traditional mechanical joints.
3Adaptability or versatility
If a gimbaled joint with bellows and flexure hinges is used, then rotational compliance is improved and reaction loading is reduced, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single integrated joint assembly: the bellows provides thermal expansion accommodation, the gimbal ring with four flexure hinges provides rotational compliance in multiple axes, and the support structures bear thrust and shear loads. This consolidation achieves high rotational compliance without proportionally increasing complexity, as all components work together in a coordinated manner.
Solution Approach 2:
The gimbal ring assembly with its four flexure hinges serves multiple functions simultaneously: it provides rotational compliance in two axes, supports thrust loads, accommodates shear loads, and allows for thermal growth. This multi-functionality reduces the need for separate components, thereby limiting the increase in overall device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces reaction loading and thermal growth, enabling a wear-free kinematic revolute interface that supports large thrust and shear loads while maintaining system integrity and reducing weight.
Implementation Method 1
A flex joint assembly utilizing a gimbaled joint with a bellows and gimbal ring assembly, featuring four flexure hinges
Implementation Method 2
mitigate reaction loading and thermal growth in high-temperature bleed-air ducting systems
Data Source
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AI summary
A flexible joint assembly (86, 198) for a joint between a first duct (82) and a second duct (84) for providing a flow of fluid, such as bleed air (88) in an aviation implementation. The flexible joint (86, 198) includes a bellows (112, 212) supported by a mounting assembly having a first support (102, 202) and a second support (104, 204), each surrounding a portion of the bellows (112, 212). A set of flexures (164) provided on a joint ring (110, 210) of the joint assemblies (86, 198) can operably couple the first support (102, 202) and the second support (104, 204).