Propulsion Rotor Platform I-Beam Stress Reduction
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Solution Overview
Problem
The I-beam configuration of airflow platforms between adjacent rotor blades in aircraft engines experiences significant radially outward centrifugal body loads, leading to deflection and high axial stresses due to the radially outward centrifugal body load, which causes high axial stresses applied to the flowpath component.
Innovation Solution
The platform design includes an axially extending I-beam with inner and outer flanges and an outer skin defining a flowpath surface, featuring laterally-extending forward and aft end flanges that abut the outer skin, providing additional support and reducing stress through increased contact surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an I-beam configuration is used for the platform, then the platform can provide structural support between rotor blades, but the platform deflects radially outward under centrifugal load causing high axial stresses
Solution Approach 1:
The patent applies composite materials by bonding a metal I-beam to a non-metallic skin panel (such as composite or titanium) to create a hybrid structure. This composite construction allows the metal I-beam to provide structural support against centrifugal loads while the non-metallic skin reduces overall density and weight, thereby reducing deflection and axial stresses under operational loads.
Solution Approach 2:
The patent merges two different materials (metal I-beam and non-metallic skin) into a single integrated platform structure. The metal I-beam and skin panel are bonded together to form a composite beam that combines the high strength of metal with the low weight of non-metallic materials, resolving the contradiction between structural support and stress reduction.
2Strength
If a metal I-beam is used for the platform, then structural strength is achieved, but weight is increased leading to greater centrifugal loads and deflection
Solution Approach 1:
The patent uses composite materials by combining a metal I-beam with a non-metallic skin panel. The metal provides necessary structural strength while the non-metallic skin has lower density, reducing the overall weight of the platform. This weight reduction decreases centrifugal body loads during rotation, thereby reducing deflection and axial stresses.
Solution Approach 2:
The patent applies local quality by using different materials in different locations of the platform structure. The metal I-beam is positioned where high strength is needed to resist bending moments, while the non-metallic skin covers the platform surface where lower weight is beneficial. This localized material distribution optimizes the strength-to-weight ratio.
3Stability of the object's composition
If the platform deflects radially outward under centrifugal load, then the I-beam structure maintains its shape, but high axial stresses are applied to the flowpath component
Solution Approach 1:
The patent applies composite materials by bonding a metal I-beam to a non-metallic skin panel. This composite construction reduces the overall density and weight of the platform, thereby reducing centrifugal body loads during rotation. The reduced loads decrease both the deflection of the I-beam and the axial stresses transmitted to the flowpath component, while the metal I-beam maintains structural stability.
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 reduces platform stresses, increases durability, and allows for simpler and more economical manufacturing by using non-metal, composite materials like graphite fibers in an epoxy resin, effectively mitigating the high axial stresses caused by deflection.
Implementation Method 1
In operation, there is a significant radially outward centrifugal body load on the platform.
Implementation Method 2
allows for simpler and more economical manufacturing by using non-metal, composite materials like graphite fibers in an epoxy resin
Data Source
AI summary
A platform for use between adjacent propulsion rotor airfoils joined to a rotor disk to provide an inner flowpath boundary includes: an axially extending I-beam supporting a radially outer skin having a flowpath surface; the I-beam including an inner I-flange disposed at an inner edge of an axially extending I-web, and an outer I-flange disposed at an outer edge of the I-web; the I-beam including a laterally-extending forward end flange at a forward end of the I-web, and a laterally-extending aft end flange at an aft end of the I-web; and the radially outer skin disposed on top of and joined to the radially outer I-flange such that the forward end flange and the aft end flange abut the outer skin.