Composite Fan Blade Fracture Pattern for Lighter Containment
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Solution Overview
Problem
Current gas turbine engine fan containment systems are heavy and inefficient, as they are designed to manage the kinetic energy of a larger fan blade portion assumed for bird strikes, which increases aircraft fuel consumption and weight, and existing methods to reduce this mass compromise aerodynamics or strength.
Innovation Solution
A kinetic energy absorptive composite article with pre-defined localized weaknesses in a pattern that controls crack propagation, allowing the fan blade to fracture safely and predictably along a specific surface, reducing the mass of the released portion and enabling a lighter containment system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan containment system is designed to manage the kinetic energy of a larger fan blade portion, then the safety and reliability are improved, but the mass of the containment system increases
Solution Approach 1:
The patent applies preliminary action by pre-defining a fracture surface within the fan blade structure before any impact occurs. This is achieved by creating a localized region with modified material properties (different fiber orientation, resin composition, or density) that will preferentially fail first under impact conditions. By preparing this weak zone in advance, the blade is designed to control where and how it breaks, ensuring that the released portion does not exceed the kinetic energy threshold that the containment system must handle, thereby reducing containment system mass while maintaining safety
Solution Approach 2:
The patent applies segmentation by dividing the fan blade into distinct functional zones: an intact region with standard material properties and a pre-defined fracture surface region with modified properties. This segmentation allows the blade to maintain full strength and aerodynamic performance in the intact region while having a controlled failure zone that will limit the size of the released portion during impact, thus reducing the kinetic energy that the containment system must manage
2Use of energy by moving object
If the diameter of fan blades is increased for improved fuel efficiency, then the fuel consumption is reduced, but the mass of the released fan blade portion increases
Solution Approach 1:
The patent applies preliminary action by pre-defining a fracture surface within the fan blade structure before any impact occurs. This is achieved by creating a localized region with modified material properties (different fiber orientation, resin composition, or density) that will preferentially fail first under impact conditions. By preparing this weak zone in advance, the blade is designed to control where and how it breaks, ensuring that the released portion does not exceed the kinetic energy threshold that the containment system must handle, thereby reducing containment system mass while maintaining safety
Solution Approach 2:
The patent applies local quality by creating a localized region with different material properties at the pre-defined fracture surface, while the rest of the blade maintains optimal material composition for strength and aerodynamics. This localized modification allows the blade to have different characteristics in different regions: the fracture surface region has controlled strength and stiffness to ensure predictable failure, while the intact region maintains full performance capabilities
3Use of energy by moving object
If the mass of the fan containment system is reduced to improve fuel consumption, then the fuel efficiency is improved, but the level of protection provided by the containment system decreases
Solution Approach 1:
The patent applies preliminary action by pre-defining a fracture surface within the fan blade structure before any impact occurs. This is achieved by creating a localized region with modified material properties (different fiber orientation, resin composition, or density) that will preferentially fail first under impact conditions. By preparing this weak zone in advance, the blade is designed to control where and how it breaks, ensuring that the released portion does not exceed the kinetic energy threshold that the containment system must handle, thereby reducing containment system mass while maintaining safety
Solution Approach 2:
The patent applies mechanics substitution by replacing the traditional approach of relying solely on a heavy containment system to manage kinetic energy with a combined approach: a modified blade structure with pre-defined fracture surfaces that control failure behavior, combined with a lighter containment system. The mechanical behavior of the blade itself is modified to actively participate in energy management by controlling where and how it fails, substituting some of the containment function with intrinsic blade design features
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 reduces the mass of the released fan blade portion, minimizing fuel consumption and allowing for lighter structural features, while maintaining safety and reliability by ensuring controlled failure and predictable crack propagation.
Implementation Method 1
a crack formed by an impact event propagates substantially along a pre-determined fracture path to separate the kinetic energy absorptive composite article into at least a first portion and a second portion
Implementation Method 2
The second sub-pattern is configured to set a threshold below which the crack does not propagate
Data Source
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AI summary
A kinetic energy absorptive composite article (31) comprising a plurality of plies, and a method of manufacturing the kinetic energy absorptive composite article. Each ply comprises a plurality of substantially parallel fibers encapsulated within a resin. A plurality of localised weaknesses (42) are comprised within the fibers of the kinetic energy absorptive composite article, the locations of the plurality of localised weaknesses forming a pre-defined pattern. The pre-defined pattern comprises a first sub-pattern (43) and a second sub-pattern (44) superposed upon the first sub-pattern. The first sub-pattern is configured so that a crack formed by an impact event propagates substantially along a predetermined fracture path to separate the kinetic energy absorptive composite article into at least a first portion and a second portion and the second sub-pattern is configured to set a threshold below which the crack does not propagate.