Composite Fan Blade Sheath Electroforming for Core Retention
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Solution Overview
Problem
Existing methods for forming leading edge sheaths in composite fan blades, such as leading edge deposition processes and direct laser metal sintering, have limitations in terms of structural integrity and retention of the core within the sheath, especially under high-temperature and pressure conditions in gas turbine engines.
Innovation Solution
The method involves additively manufacturing a core and securing it to a mandrel, followed by electroforming a leading edge sheath directly onto both, with local thickening to facilitate retention and bonding of the blade body, using techniques like direct metal laser sintering and inserting alignment pins and wedges for separation and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If leading edge deposition processes or direct laser metal sintering are used to form the leading edge sheath, then the blade can be manufactured with complex geometry, but the structural integrity and retention of the core within the sheath deteriorates under high-temperature and pressure conditions
Solution Approach 1:
The patent employs a composite structure consisting of a metal leading edge sheath (providing strength and thermal resistance) combined with a ceramic core (providing thermal insulation). This composite material approach allows the blade to maintain complex geometry while achieving the structural integrity and thermal stability required for high-temperature gas turbine operation, resolving the contradiction between geometric versatility and structural reliability.
2Ease of manufacture
If the leading edge sheath is formed by conventional deposition processes, then manufacturing is simplified, but the retention of the core by the sheath deteriorates
Solution Approach 1:
The patent incorporates protrusions on the core surface and corresponding recesses in the sheath interior before final assembly. This preliminary action of creating mechanical interlocking features during the manufacturing process ensures reliable core retention without requiring complex post-assembly fastening operations, thus maintaining manufacturing simplicity while improving core retention reliability.
Solution Approach 2:
The patent applies local thickening of the sheath at specific locations where the core protrusions engage, creating localized reinforcement zones. This local quality approach provides enhanced core retention at critical interfaces while maintaining overall sheath simplicity and ease of manufacture in non-critical areas.
3Weight of moving object
If the core is additively manufactured with complex internal structures, then weight is reduced and strain capabilities are improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs additively manufactured cores with controlled porous or lattice internal structures. These porous materials provide significant weight reduction while maintaining adequate structural strength and strain capabilities. The additive manufacturing process inherently handles the manufacturing complexity of such complex internal geometries, transforming what would be a manufacturing challenge into a routine process capability.
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 approach results in a lightweight, structurally sound composite fan blade with improved strain capabilities and ease of fabrication, enhancing the retention of the core by the sheath and enabling efficient assembly and repair.
Implementation Method 1
electroforming a leading edge sheath directly onto the core and the mandrel
Implementation Method 2
direct metal laser sintering (DMLS) processes
Data Source
AI summary
A blade fabrication method is provided and includes additively manufacturing a core, securing the core to a mandrel, electroforming a leading edge sheath directly onto the core and the mandrel and removing the mandrel from the core and the leading edge sheath.