Gas Turbine Radial Element Stiffness for Weld Durability
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Solution Overview
Problem
The existing supporting structures for gas turbine engines face challenges with thermal stress and durability due to high mechanical and thermal loads, leading to reduced lifespan of welded joints, which are exacerbated by the use of prefabricated components with traditional weld joints.
Innovation Solution
The supporting structure incorporates radial elements with a region of reduced stiffness near the leading edge, redistributing thermal stress and load concentration, and varying wall thickness to alleviate stress concentrations, thereby extending the life of the weld joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If prefabricated supporting structures with welded joints are used to reduce weight, then the weight of the supporting structure is reduced, but the thermal stress and durability of the welded joints deteriorate
Solution Approach 1:
The patent applies local quality by creating a region of reduced stiffness specifically at the leading edge of the radial element, while maintaining normal wall thickness in other regions. This localized modification allows the structure to redistribute thermal stresses away from the welded joint without compromising overall structural integrity or requiring complete redesign of the entire component.
Solution Approach 2:
The patent changes the physical parameter of wall thickness in a specific region to alter the stiffness characteristics. By reducing the wall thickness at the leading edge, the local stiffness is reduced, which changes the stress distribution pattern and protects the welded joint from thermal stress concentration while maintaining the weight reduction benefits of the prefabricated structure.
2Ease of manufacture
If traditional weld joints are used to connect radial elements to rings, then the manufacturing process is simplified, but thermal stress concentration at the leading edge increases
Solution Approach 1:
The patent introduces a localized region of reduced stiffness at the leading edge, creating a specific structural feature in that location while leaving the rest of the radial element unchanged. This allows the welded joint to remain simple and manufacturable, while the local structural modification at the leading edge redistributes the thermal stresses away from the weld.
Solution Approach 2:
The region of reduced stiffness acts as an intermediary element between the welded joint and the high thermal stress environment. It serves as a stress redistribution zone that protects the welded joint from direct thermal stress concentration, allowing the simple welded connection to remain effective without being directly exposed to the harmful thermal stresses.
3Ease of manufacture
If uniform wall thickness is used in radial elements, then the manufacturing process is simplified, but stress concentrations occur at the leading edge under thermal load
Solution Approach 1:
The patent modifies the uniform wall thickness design by creating a localized region with reduced thickness at the leading edge. This local variation in wall thickness creates a corresponding region of reduced stiffness that redistributes thermal stresses, while the majority of the radial element maintains uniform thickness for simplified manufacturing.
Solution Approach 2:
The patent changes the wall thickness parameter specifically at the leading edge region, creating a non-uniform thickness distribution that optimizes stress distribution under thermal loading. This parameter change is localized to where it is most needed, allowing simplified manufacturing processes to be used for the majority of the component while still achieving stress concentration mitigation.
Data Source
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AI summary
The invention concerns a supporting structure (27) for a gas turbine engine (1), said structure (27) comprising an inner ring (20), an outer ring (21), and a plurality of circumferentially spaced, load carrying radial elements (22) connecting the inner and outer rings (20, 21), said radial elements (22) being configured to transfer loads between the inner ring (20) and the outer ring (21), wherein a gas channel for a primary axial gas flow is defined between the inner and outer rings (20, 21), wherein the supporting structure (27) has an inlet side for primary gas flow entrance and an outlet side for primary gas outflow, wherein the radial elements (22) have an airfoil shape with a leading edge (221) directed towards the inlet side, a trailing edge (222) directed towards the outlet side, and two opposite sides (223, 224) connecting the leading edge (221) and the trailing edge (222), and wherein at least a first of said radial elements (22a, 22b) is connected to an adjacent part (30) of the supporting structure (27) via a weld joint (50) that extends across the leading edge (221) and circumferentially at least partly around the first radial element (22a, 22b). The invention is characterized in that the first radial element (22a, 22b) is provided with a region of reduced stiffness (10) in the vicinity of the leading edge (221). The invention also concerns a gas turbine engine (1) comprising a supporting structure (27) of the above type. The invention further comprises a method of manufacturing a supporting structure (27) of the above type.