Light-Weight Sheet Welding for Gas Turbine Sound Absorption
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Solution Overview
Problem
Existing methods for manufacturing sandwich-like light-weight sheets for sound absorption in gas turbines face issues such as debonding, galvanic corrosion, and material limitations due to adhesive joining and stiff forming processes, which can lead to assembly failures and increased maintenance costs.
Innovation Solution
A method involving a sandwich-like construction with a grid-like intermediate layer and a perforated bottom layer, where the layers are welded together to achieve a defined surface curvature, allowing for accurate weld points and using metallic materials for all layers to prevent corrosion, with the acoustically operative cover layer separate from structural considerations, and employing smooth expanded metal and titanium strips for enhanced sound absorption and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive joining is used to assemble the sandwich construction, then the manufacturing process is simple and easy to implement, but the assembly suffers from debonding over time and galvanic corrosion when different materials are used
Solution Approach 1:
The patent replaces the chemical bonding system (adhesive joining) with a mechanical bonding system (self-piercing rivets). This substitution eliminates the debonding and galvanic corrosion issues associated with adhesives while maintaining ease of assembly. The rivets create permanent mechanical connections that are resistant to both debonding and corrosion.
Solution Approach 2:
The patent changes the joining method from adhesive-based chemical bonding to rivet-based mechanical bonding. This parameter change in the joining mechanism fundamentally resolves the reliability issues while preserving manufacturing simplicity, as the riveting process is straightforward and does not require complex adhesive application or curing procedures.
2Ease of manufacture
If adhesive joining is used to assemble the sandwich construction, then the manufacturing process is simple, but very high stresses arise during forming that can lead to failure of the assembly
Solution Approach 1:
The patent performs the joining operation before the forming process. The self-piercing rivets are installed in the flat sandwich construction, creating strong mechanical connections that can withstand the subsequent high stresses of forming operations. This preliminary joining action ensures the assembly maintains its integrity throughout the forming process without the stresses degrading a pre-existing adhesive bond.
3Ease of manufacture
If adhesive joining is used, then the manufacturing process is straightforward, but maintenance and repair costs increase due to assembly failure
Solution Approach 1:
The patent replaces adhesive joining with self-piercing rivet joining, creating a mechanically robust assembly that resists debonding and galvanic corrosion. This mechanical connection system significantly reduces maintenance and repair costs by eliminating the common failure modes associated with adhesive joints, thereby improving the long-term economy of the sandwich construction despite the slightly more complex initial joining process.
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 method ensures a robust, stress-free assembly with improved sound absorption across a wide frequency range, avoiding debonding and corrosion issues, and allowing the use of high-strength materials like titanium by decoupling acoustic and mechanical requirements, thus enhancing the reliability and longevity of the light-weight sheet.
Implementation Method 1
A portion of the sound energy is converted to heat in the porous cover layer and, through this, achieves significant absorption.
Data Source
AI summary
The invention is directed to a method for manufacturing a sandwich like constructed light weight sheet with sound absorption characteristics, by which an acoustically absorbing cover layer, a substantially grid shape configured first intermediate layer and a bottom layer are bound together, wherein the light weight sheet has a defined surface.