Wing-Folding Mechanism Interface for Distributed Load Transfer
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Solution Overview
Problem
Existing wing folding mechanisms in aircraft rely on small contact surfaces for load transfer, leading to high bending moments and potential bolt failure, which are inefficient and prone to structural weaknesses.
Innovation Solution
An interface for wing folding mechanisms using an attachment pad with a larger surface area to transmit loads perpendicularly, reducing the likelihood of bolt bending failure and enhancing load transfer efficiency, accompanied by access openings for easy maintenance and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lugs with shear bolts are used to connect wing sections, then the wing folding mechanism can be assembled, but the contact surface area is small leading to high bending moments and potential bolt failure
Solution Approach 1:
The invention transitions from a point-contact lug-bolt connection to a surface-contact pad connection. The attachment pad provides a distributed contact area between the interface and the wing section, fundamentally changing the dimensional nature of the load transfer from linear (bolt axis) to areal (pad surface), thereby reducing stress concentration and bending moments on fasteners
Solution Approach 2:
The invention changes the geometric parameter of the connection interface by replacing small lugs with larger attachment pads. This parameter change increases the contact surface area significantly, which directly reduces the bending moments and stress on bolts by distributing loads over a larger area, thereby preventing bolt failure
2Reliability
If a larger contact surface is used for load transfer, then bolt bending failure is reduced, but the interface size and weight increase
Solution Approach 1:
The invention optimizes the size parameters of the attachment pad to achieve the minimum required contact area for reliable load transfer. By carefully selecting the pad dimensions, the design achieves sufficient reliability to prevent bolt failure while minimizing the additional weight compared to traditional lug connections
Solution Approach 2:
The attachment pad is designed as a composite structure integrating the driven gear interface and the load-bearing attachment surface. This composite design allows efficient load transfer paths while optimizing material usage, achieving high reliability without excessive weight penalty
3Device complexity
If traditional lug connections are used, then the structure is simple, but load transfer efficiency is low and bending moments are high
Solution Approach 1:
The invention improves load transfer efficiency by transitioning from point-contact lugs to surface-contact pads. This dimensional change enables more efficient distribution of aerodynamic and inertial loads across the interface, reducing peak stresses and bending moments while maintaining structural integrity
Solution Approach 2:
The attachment pad serves multiple functions simultaneously: it provides the driven gear interface for actuator connection, provides a large contact area for efficient load transfer, and serves as a mounting surface for wing section attachment. This multi-functionality achieves high load transfer efficiency without proportionally increasing complexity
Data Source
Figure 1A
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Figure 2
AI summary
An interface (201) for a wing folding mechanism of an aircraft. The interface has a central region (203) comprising an internal surface (205), the internal surface being suitable for engaging a driven gear of a rotary actuator, and an attachment pad (211) extending away from the central region (203) in a first direction for attaching a surface to the interface (201). The interface (201) can be used as part of the casing of a Geared Rotary Actuator (200). Also described are related wing assemblies, and aircraft (100) and related methods.