Tangential Restraints Convert Radial Loads to Membrane Tension
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Solution Overview
Problem
Aircraft fan cowls deflect under load, leading to increased drag and fuel consumption, and conventional solutions like increasing material thickness or adding ribbing structures result in weight gain and decreased efficiency.
Innovation Solution
The implementation of tangential restraints that convert radial loads into membrane tension by contacting the fixed nacelle portion, reducing deflection and stiffening the fan cowl, while allowing for lighter construction and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fan cowl material thickness is increased to reduce deflection, then structural strength is improved, but aircraft weight increases
Solution Approach 1:
The patent changes the structural parameter from material thickness to geometric configuration by introducing a tangential restraint system. This restraint system converts radial loads into membrane tension through geometric arrangement, allowing thin material to achieve the same structural strength as thick material would provide alone.
Solution Approach 2:
The patent creates a composite structural system combining the fan cowl shell with the tangential restraint mechanism. This composite action allows the thin cowl and restraint system together to provide equivalent strength to a thick cowl, reducing overall weight while maintaining structural integrity.
2Stability of the object's composition
If additional ribbing structure is added to reduce deflection, then structural stiffness is improved, but device complexity increases
Solution Approach 1:
The patent changes the approach from adding internal reinforcement elements (ribs) to applying external geometric constraints (tangential restraints). This transforms the stiffness problem from one solved by material distribution to one solved by geometric configuration, reducing structural complexity.
Solution Approach 2:
The patent introduces tangential restraint elements as intermediary components that mediate between the applied radial loads and the fan cowl structure. These restraints convert the loading mode rather than directly reinforcing the cowl, simplifying the overall structure compared to adding multiple ribs.
3Object-affected harmful factors
If fan cowl deflection is reduced through conventional methods, then aerodynamic performance is improved, but fuel consumption increases due to weight gain
Solution Approach 1:
The patent changes the weight parameter by using geometric constraints instead of additional material. This parameter change reduces the mass of the fan cowl assembly while maintaining the aerodynamic performance needed to minimize drag, thereby reducing fuel consumption.
Solution Approach 2:
The composite restraint system provides the necessary structural performance to reduce deflection and drag without the weight penalty of conventional reinforcement, directly addressing the fuel consumption issue through weight reduction.
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 tangential restraints effectively reduce fan cowl deflection, enabling the use of thinner materials, which decreases weight and fuel consumption while maintaining structural integrity and efficiency.
Implementation Method 1
a tangential restraint configured to convert at least a portion of a radial load received by the fan cowl to membrane tension by contacting a portion of the fixed nacelle portion
Implementation Method 2
a tangential restraint configured to transfer load to the fixed nacelle portion when the fan cowl latch and the nacelle latch are coupled together
Data Source
AI summary
Systems and methods are provided for an aircraft propulsor with a fan cowl with one or more tangential restraints. The tangential restraints may be configured to enter respective tangential receiving portions of a fixed portion of the aircraft propulsor. The fan cowl may receive a load that may include a bending load. The tangential restraints may be configured to convert the bending load to membrane tension and thus decrease deflection of the fan cowl. The fan cowl may be a translating sleeve used for a reverse thrust.