Bi-Metallic Containment Ring for Gas Turbine Engine Weight Reduction
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Solution Overview
Problem
Containment rings for gas turbine engines face challenges in meeting federal requirements while minimizing mass, as existing solutions often compromise between strength and ductility, leading to either excessive weight or inadequate containment performance.
Innovation Solution
A bi-metallic containment ring design comprising a first portion with high ductility and low strength, and a second portion with low ductility and high strength, optimized in volume ratio to provide effective containment while reducing mass, using materials like Inconel alloys and stainless steel, and coupled through techniques such as inertia welding or mechanical fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If containment ring mass is increased to meet federal requirements, then containment strength is improved, but device weight increases
Solution Approach 1:
The containment ring is constructed as a composite structure with an inner ring of high-strength material (Inconel 718 or 625) and an outer ring of high-ductility material (austenitic stainless steel 304 or 316). This bi-metallic composite design allows the high-strength inner ring to provide containment capability while the high-ductility outer ring absorbs impact energy, achieving federal requirements with reduced mass compared to homogeneous high-strength designs.
Solution Approach 2:
Different regions of the containment ring are assigned different material properties optimized for their specific functions: the inner ring uses high-strength material to resist penetration by disk fragments, while the outer ring uses high-ductility material to absorb kinetic energy through deformation. This localized material assignment resolves the contradiction by ensuring each region contributes optimally to containment without requiring the entire structure to be over-engineered for maximum strength.
2Strength
If high-strength material is used throughout the containment ring, then containment capability is improved, but energy absorption capacity deteriorates
Solution Approach 1:
The bi-metallic composite structure combines high-strength Inconel material for the inner ring with high-ductility austenitic stainless steel for the outer ring. The high-strength inner ring provides resistance to disk fragment penetration, while the high-ductility outer ring absorbs kinetic energy through plastic deformation. This composite approach simultaneously achieves both penetration resistance and energy absorption capacity that would be difficult to obtain with a single material.
Solution Approach 2:
The inner ring is assigned high-strength material properties optimized for resisting penetration by separated disk fragments, while the outer ring is assigned high-ductility material properties optimized for absorbing kinetic energy through deformation. This spatial differentiation of material properties allows each region to excel at its specific function without compromising the other.
3Loss of energy
If high-ductility material is used throughout the containment ring, then energy absorption is improved, but containment strength deteriorates
Solution Approach 1:
The containment ring uses a composite structure where the outer ring is made of high-ductility austenitic stainless steel for energy absorption, while the inner ring is made of high-strength Inconel material for penetration resistance. This composite design allows the high-ductility material to be used extensively for energy absorption without compromising containment strength, as the high-strength inner ring provides the necessary structural integrity.
Solution Approach 2:
The outer ring is assigned high-ductility material properties to maximize kinetic energy absorption through plastic deformation, while the inner ring is assigned high-strength material properties to provide resistance to disk fragment penetration. This localized assignment allows the high-ductility material to be used where it is most effective (outer region for energy absorption) without compromising overall containment strength.
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 bi-metallic containment ring effectively absorbs energy during containment events, meeting federal requirements with reduced mass, offering weight savings for gas turbine engines and vehicles, by leveraging the ductility of one material to expand and absorb energy, while the high-strength material absorbs initial impact.
Implementation Method 1
the high-strength material absorbs initial impact
Implementation Method 2
leveraging the ductility of one material to expand and absorb energy
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
A containment ring (12) includes a first portion (100) having a first ring composed of a first material with a first ductility. The containment ring also includes a second portion (102) coupled to the first ring. The second portion is composed of a second material having a second ductility that is less than the first ductility and the first ductility is greater than about forty percent elongation.