External Aircraft Engine Enclosure Stiffening at Welded Mounts
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Solution Overview
Problem
Externally-mounted engine components for gas turbine engines, such as oil tanks, face high static and dynamic stresses due to their large size, weight, and remote placement from the engine's rotation axis, leading to potential early failure at weld locations and mounting brackets.
Innovation Solution
The component features a sealed enclosure with a protrusion extending along the weld line and mounting bracket, providing additional stiffness through strategically varied protrusion dimensions and additional stiffeners to mitigate stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the component is made from casted and sheet metal portions welded together, then manufacturing flexibility and design adaptability are improved, but structural strength and reliability deteriorate due to stress concentrations at weld locations
Solution Approach 1:
The patent applies local quality by adding a protrusion specifically at the weld line location where stress concentration occurs. This localized structural modification reinforces only the critical area without requiring changes to the entire component, thereby maintaining design flexibility while improving reliability at the vulnerable weld joint.
Solution Approach 2:
The component is divided into separate casted and sheet metal portions that are welded together, allowing each portion to be optimized for its specific function and manufacturing process. This segmentation enables design adaptability while the added protrusion compensates for the reliability issue at the joint.
2Area of stationary object
If the component is mounted remotely from the engine's rotation axis, then packaging efficiency and spatial arrangement are improved, but structural strength and stability worsen due to increased static and dynamic stresses
Solution Approach 1:
The protrusion is strategically placed at the weld line and mounting bracket areas to provide localized reinforcement exactly where the remote mounting causes highest stress concentrations. This allows the component to maintain its remote mounting position for packaging efficiency while strengthening the vulnerable areas through targeted structural modification.
Solution Approach 2:
The protrusion is incorporated into the component design before mounting, proactively reinforcing areas that will experience high stresses during operation. This preliminary reinforcement prevents stress concentration issues before they lead to failure, allowing the component to safely operate at remote locations.
3Reliability
If protrusions are added to increase stiffness and reduce stress concentrations, then structural reliability is improved, but component weight and complexity increase
Solution Approach 1:
Rather than adding complex reinforcement structures throughout the component, the patent uses a simple protrusion feature localized at the critical weld line. This minimal structural addition provides the necessary stiffness and stress distribution improvement without significantly increasing overall component complexity or weight.
Solution Approach 2:
The protrusion provides more reinforcement than the minimum theoretically required, creating a stress distribution buffer that ensures reliability under varying operational conditions. This partial over-reinforcement is concentrated at the critical location rather than distributed throughout the entire component, minimizing added complexity.
Data Source
AI summary
A component for an aircraft engine. The component is mountable externally to a core of the aircraft engine. The component includes an enclosure having a wall circumscribing a sealed inner chamber. The wall has an inner surface and an outer surface. The wall has a first wall portion welded to a second wall portion along a weld line extending about a perimeter of the enclosure. A mounting bracket is disposed on the outer surface for mounting the component to the core. A protrusion protrudes from one or more of the outer surface and the inner surface and extends along one or more of the outer surface and the inner surface concentrically with the weld line. Sn additional protrusion protrudes from one or more of the outer surface and the inner surface. The additional protrusion extends from the protrusion to the mounting bracket.