Fiber-Grooved Gear Wheel for Fragment Containment
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Solution Overview
Problem
Gear wheel breakage in gas turbine engines can lead to uncontrolled ejection of high-kinetic-energy fragments, potentially damaging surrounding components and disrupting engine function, with existing solutions either increasing transmission weight or not adequately addressing the risk of fragment propagation.
Innovation Solution
A gear wheel design featuring a groove on its outer periphery with fibers arranged in the circumferential direction, which supports fragments upon breakage, allowing them to be crushed and retained longer, reducing the mass and kinetic energy of fragments to prevent damage upon ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the transmission casing is designed with increased strength to prevent fragment penetration, then the protection against fragment damage is improved, but the overall weight of the transmission increases
Solution Approach 1:
The fiber wrapping is installed on the gear wheel before operation, creating a containment system in advance. When breakage occurs, the pre-positioned fibers immediately contain the fragments, preventing them from penetrating the casing without requiring the casing itself to be excessively strong.
Solution Approach 2:
The fiber wrapping acts as an intermediary containment layer between the gear wheel and the transmission casing. Instead of relying solely on the casing to stop fragments, the fiber wrapping serves as a intermediate barrier that captures and contains fragments, reducing the burden on the casing strength.
2Strength
If composite material reinforcement elements are added to the gear wheel to improve strength, then the load-bearing capacity is improved, but the complexity of the gear wheel structure increases
Solution Approach 1:
The gear wheel combines metallic support ring with composite material fiber wrapping. The metallic component provides structural support while the composite fiber wrapping provides reinforcement and breakage containment, leveraging the advantages of both material types to achieve improved strength without excessive complexity.
Solution Approach 2:
The fiber wrapping functions as a flexible containment shell that conforms to the gear wheel geometry. This thin-film approach provides comprehensive reinforcement and fragment containment without adding significant structural complexity or weight compared to rigid reinforcement methods.
3Strength
If fibers are permanently connected to the gear wheel to support loads, then the structural strength is improved, but the ability to contain fragments independently upon breakage is reduced
Solution Approach 1:
The fiber wrapping system transitions from a static structural role to a dynamic containment role upon breakage. The fibers are positioned to provide load support during normal operation, but upon gear wheel failure, they dynamically switch to containing fragments through their elastic properties, adapting their function based on operational conditions.
Solution Approach 2:
The fiber wrapping is pre-positioned around the gear wheel to provide cushioning and containment capability before breakage occurs. This advance preparation ensures that when breakage happens, the fragments are immediately contained by the pre-positioned fiber network, rather than relying on permanent structural connections that would prevent independent fragment containment.
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 design effectively reduces the probability of fragment penetration through the transmission casing and minimizes the risk of engine damage by maintaining the fragments' rotation and crushing them into smaller, less damaging pieces, thus ensuring safer operation.
Implementation Method 1
the kinetic energy of the rotating gear wheels is a square of the product of the mass of the gear wheel and the rotational speed. In the case of breakage of a gear wheel, fragments of the gear wheel are flung out of the former rotation path along a tangential flight path with varying force depending on the current kinetic energy.
Data Source
AI summary
A gear wheel of a transmission, in particular of a transmission of a gas turbine engine is described, which is designed with a groove which extends in the circumferential direction on the outer periphery of a base body of the gear wheel and in which fibers running at least in the circumferential direction are arranged. The fibers surround the base body in the circumferential direction, wherein the fibers at least partially support the operating loads on the gear wheel only on a breakage of the base body.