Gas Turbine Annulus Strut Support via Relocated Abutment Shoulder
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Solution Overview
Problem
Existing gas turbine engine designs face challenges in providing structural support for annulus components in hot environments, where high temperatures reduce material properties and increase the likelihood of defects due to stress concentration at fillet radii, making crack detection and load-bearing capability inadequate.
Innovation Solution
The solution involves relocating the abutment shoulder radially inwardly of the cross pin and outside the annulus, using a spigot and cross pin configuration to secure struts, which reduces stress concentration and enhances load-bearing capacity while allowing easier inspection and crack detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the abutment shoulder is positioned at the fillet radius in high-temperature environments, then the structural support function is provided, but stress concentration increases and material properties deteriorate due to heat
Solution Approach 1:
The invention extracts the abutment shoulder from the high-temperature zone inside the annulus and relocates it to the cooler external environment. The strut passes through the annulus with the abutment shoulder positioned outside, separating the load-bearing function from the high-temperature exposure area, thereby preserving material strength while maintaining structural support.
Solution Approach 2:
The strut acts as an intermediary element that transmits loads across the annulus while isolating the abutment shoulder from high-temperature effects. The strut body withstands the thermal environment, while the critical abutment shoulder remains in the cooler external zone, protecting the stress concentration area from thermal degradation.
2Device complexity
If the abutment shoulder is positioned inside the annulus, then the support structure is compact, but crack detection becomes difficult and stress concentration increases
Solution Approach 1:
The abutment shoulder is extracted from the interior of the annulus and repositioned externally, making it accessible for inspection while maintaining structural functionality. This relocation allows visual and non-destructive testing methods to access the critical stress concentration area without disassembling components.
Solution Approach 2:
The external positioning of the abutment shoulder allows the structure to be self-inspectable. The critical area where cracks are most likely to initiate is automatically positioned in a location that facilitates routine maintenance and inspection activities without requiring complex access procedures.
3Ease of manufacture
If the abutment shoulder is located radially outwardly of the cross pin, then the assembly is simpler, but stress concentration occurs at the fillet radius reducing reliability
Solution Approach 1:
The abutment shoulder is extracted from the high-stress fillet radius area and relocated to a position where stress concentrations are minimized. By positioning it externally and radially inwardly of the cross pin, the critical shoulder area is removed from the high-stress zone while maintaining the structural assembly's functionality.
Solution Approach 2:
The invention applies local quality by differentiating the positioning of various components: the cross pin remains at the fillet radius to provide structural connection, while the abutment shoulder is positioned in a lower-stress external location. This allows each component to be optimally positioned for its specific function, with the shoulder in a low-stress zone and the pin in the structural connection zone.
Data Source
AI summary
The annulus is bound by an inner hub wall and an outer casing and includes a support structure, the support structure bearing the inner hub wall; at least one spigot passing through the hub wall and at least one strut arranged to pass through the spigot of the inner hub wall and across the annulus. The strut has a first end having an abutment arm extending to form an abutment shoulder. Alignable holes pass through the abutment arm and the spigot and these holes are configured to receive a cross pin which is in turn configured to fit snugly through the holes. The configuration is such that, the abutment rim and abutment shoulder are located radially inwardly of the holes and cross pin and outside of the annulus.