Gas Turbine Auxiliary Mounting Fuse for Fan Blade Out Loads
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Solution Overview
Problem
Conventional mounting systems for auxiliary components in gas turbine engines fail to withstand high shock loads from fan blade out events, leading to component separation or damage due to inadequate design to handle rotor imbalance loads.
Innovation Solution
A mechanical fuse is integrated into the mounting assembly, featuring a support bracket with a bearing member and a mechanical fuse that includes radially inner and outer walls with annular cuts, designed to fracture and absorb energy during overload events, maintaining attachment to the engine case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mounting system is designed to withstand high shock loads from fan blade out events, then the reliability and strength of the mounting system improve, but the weight of the gearbox and mounting components increases
Solution Approach 1:
The patent incorporates a mechanical fuse element with a predetermined fracture load that acts as a protective mechanism before the full shock load is transmitted to the gearbox. This fuse element absorbs and limits the shock load from fan blade out events, protecting the gearbox while allowing the use of lighter-weight materials that would not otherwise survive such extreme loads.
Solution Approach 2:
The mechanical fuse serves as an intermediary component between the mounting system and the gearbox. It mediates the transmission of shock loads by fracturing at a predetermined load threshold, thereby protecting the gearbox from direct exposure to full shock loads while enabling the use of lighter-weight materials.
2Weight of moving object
If the mounting system is designed to be lightweight using light-weight materials, then the weight of the gearbox decreases, but the strength and durability to withstand fan blade out loads deteriorates
Solution Approach 1:
The mechanical fuse element is designed with a predetermined fracture load that is lower than the strength limits of the lightweight gearbox components. This provides beforehand protection by limiting the maximum load transmitted to the gearbox, enabling the use of light-weight materials that would otherwise be too weak to survive fan blade out events.
Solution Approach 2:
The mechanical fuse element is designed as a sacrificial component that is intended to fracture and be replaced after a fan blade out event. This disposable element protects the expensive, lightweight gearbox from damage while accepting that the fuse itself will be destroyed in the process.
3Device complexity
If the mounting system is designed without mechanical fuses to reduce complexity, then the device complexity decreases, but the ability to protect against rotor imbalance loads and component damage deteriorates
Solution Approach 1:
The mounting system is segmented into distinct functional elements: the support bracket, bearing member, and mechanical fuse element. This segmentation allows the fuse element to be designed as a simple, dedicated protective component with a single function (fracturing at predetermined load), reducing overall system complexity while improving reliability.
Solution Approach 2:
The mechanical fuse element serves as a simple intermediary component that adds minimal complexity to the mounting system while providing critical protection against rotor imbalance loads. Its simple fracture-based protection mechanism significantly improves reliability without requiring complex control systems or multiple protective components.
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 mechanical fuse effectively absorbs and distributes high shock loads, preventing component separation and damage by allowing controlled energy absorption and maintaining attachment to the engine case during fan blade out events.
Implementation Method 1
a bearing member disposed within the intermediate portion
Implementation Method 2
a mechanical fuse disposed within the bearing member. In various embodiments, the mechanical fuse includes a central portion, a radially inner wall attached to the central portion and a radially outer wall with respect to a central axis extending through the central portion of the mechanical fuse. In various embodiments, the radially inner wall and the radially outer wall are separated by a gap. In various embodiments, the mechanical fuse includes a first fuse section extending annularly about the radially outer wall. In various embodiments, the first fuse section is formed by a first annular cut extending circumferentially about the radially outer wall with respect to the central axis.
Data Source
AI summary
An assembly for mounting an auxiliary component to an engine case of a gas turbine includes a support bracket, the support bracket having a first end configured for attachment to a first flange of the engine case, a second end configured for attachment to a second flange of the engine case, and an intermediate portion located intermediate the first end and the second end; a bearing member disposed within the intermediate portion; and a mechanical fuse disposed within the bearing member.