Covered Turbine Airfoil Weld Layout for Strength-Weight Balance
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Solution Overview
Problem
Existing methods for constructing hollow airfoils for gas turbine engines face challenges in achieving a strong and efficient attachment of cover skins to the airfoil body, particularly in maintaining a robust weld configuration that balances stress distribution and weight reduction.
Innovation Solution
The airfoil design incorporates a recessed region with ribs that loop around pockets, where the cover skin is welded along a weld path with a ratio of weld width to rib width between 3:1 and 4:1, featuring a serpentine profile and raised protrusions to support the cover skins, enhancing the structural integrity and reducing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the cover skin is welded to the airfoil body with a narrow weld path, then the weight is reduced, but the stress distribution becomes concentrated and structural integrity deteriorates
Solution Approach 1:
The weld path width is optimized to create different local characteristics: wider sections (3-4 times rib width) at stress concentration points for strength, and narrower sections elsewhere for weight reduction. This localized variation in weld geometry achieves both weight reduction and stress distribution improvement simultaneously.
2Strength
If the weld path width is increased to distribute stress, then structural integrity improves, but material usage increases and weight is added
Solution Approach 1:
The weld path is segmented into multiple sections with different widths rather than using a uniform width throughout. This segmentation allows the weld to provide maximum strength only where stress concentrations occur, while minimizing material usage in low-stress areas, thereby resolving the contradiction between strength and weight.
3Strength
If ribs are added to the recessed region to improve stress distribution, then structural integrity improves, but device complexity increases
Solution Approach 1:
The ribs serve multiple functions simultaneously: they provide stress distribution, support the cover skin during welding, define the recessed region geometry, and facilitate the weld path routing. This multi-functionality reduces the need for additional separate structural elements, thereby limiting the increase in device complexity while achieving improved stress distribution.
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
This design improves the structural integrity and load distribution of the airfoil by reducing stress concentrations and minimizing material usage, while maintaining a lightweight structure, thus enhancing the performance and durability of the gas turbine engine components.
Implementation Method 1
At least one cover skin is welded to the airfoil body along the at least one rib to enclose the recessed region
Data Source
Figure 1
Figure 2
Figure 3~3B
AI summary
An airfoil (61) for a gas turbine engine (20) according to an example of the present disclosure includes, among other things, an airfoil body (68) defining a recessed region (78) and including at least one rib (74) dimensioned to loop about a respective pocket (72) within a perimeter (78P) of the recessed region (78). At least one cover skin (70) is welded to the airfoil body (68) along the at least one rib (74) to enclose the recessed region (78). The at least one cover skin (70) is welded to the at least one rib along a respective weld path (88). The weld path (88) defines a weld width (W2), the at least one rib (74) defines a rib width (W1), and a ratio of the weld width (W2) to the rib width (W1) is equal to or greater than 3:1 for each position along the weld path (88). A method of forming a gas turbine engine (20) component is also disclosed.