Aircraft Wing Rib Attachment Using Ball Stud Shear Tie
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Solution Overview
Problem
Conventional shear ties used to attach aircraft wing ribs to stringers are heavy and bulky, transferring unnecessary rotational moments, which can negatively impact aircraft performance.
Innovation Solution
An apparatus comprising an insert with an interference fit, a shear tie with a socket, a ball stud with a shaft and ball, and a fastener to secure the ball within the socket, allowing for lighter and less bulky attachment of ribs to panels, specifically designed to transfer translational forces while preventing rotational moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shear ties are used to attach ribs to panels, then rotational moments are transferred from the skin to the rib, but the shear ties become heavy and bulky, adversely impacting aircraft performance
Solution Approach 1:
The patent extracts the rotational moment transfer function from the shear tie by introducing a separate moment-resisting mechanism (clevis and cotter pin assembly). The shear tie is reduced to only its essential function of transferring translational shear forces, significantly reducing its weight and bulk while maintaining overall structural reliability.
Solution Approach 2:
The attachment system is segmented into distinct functional components: a simplified shear tie for translational force transfer, and a separate clevis-cotter pin mechanism for rotational moment transfer. This segmentation allows each component to be optimized independently, reducing the weight of the shear tie while maintaining the necessary rotational restraint through the specialized moment-resisting assembly.
2Reliability
If conventional shear ties are used to attach ribs to panels, then rotational moments are transferred from the skin to the rib, but the shear ties become bulky, increasing installation complexity
Solution Approach 1:
The rotational moment transfer function is extracted from the shear tie and assigned to a dedicated moment-resisting mechanism. This extraction reduces the shear tie to a simpler, less bulky component that only handles translational shear forces, while the clevis-cotter pin assembly provides the necessary rotational restraint in a more compact and installation-friendly manner.
Solution Approach 2:
The attachment system is divided into modular functional segments: a compact shear tie for force transfer and a separate clevis-cotter pin mechanism for moment resistance. This segmentation reduces the bulkiness of individual components and simplifies installation by allowing each component to be optimized for its specific function rather than combining all functions in a single bulky assembly.
3Weight of moving object
If lighter shear ties are used to reduce weight, then aircraft performance is improved, but the ability to transfer rotational moments may be compromised
Solution Approach 1:
The attachment system segments the load transfer functions into two specialized mechanisms: a lightweight shear tie optimized for translational force transfer, and a dedicated clevis-cotter pin assembly optimized for rotational moment transfer. This segmentation allows the shear tie to be minimized in weight while the moment-resisting mechanism provides reliable rotational restraint through its geometric design and mechanical locking features.
Solution Approach 2:
The rotational moment transfer function is extracted from the shear tie and assigned to a specialized moment-resisting mechanism. This extraction enables the shear tie to be significantly reduced in weight while maintaining reliable rotational moment transfer through the separate clevis-cotter pin assembly, which uses mechanical interlocking rather than relying on the shear tie's structural capacity.
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 solution provides a lighter and less bulky attachment method, reducing material costs and installation complexity, while enhancing lift capacity by minimizing unnecessary weight and torque transfer.
Implementation Method 1
an insert that is configured to be attached, via an interference fit, to a hole in the rib
Data Source
AI summary
Examples include an apparatus configured for attaching a rib of an aircraft wing to a panel of the aircraft wing, the apparatus including: an insert that is configured to be attached, via an interference fit, to a hole in the rib; a shear tie including a socket at a first end of the shear tie, where the shear tie is configured to be attached to the panel at a second end of the shear tie; a ball stud including a shaft and a ball that is opposite the shaft, where the shaft is configured to be attached to the insert and the ball is configured to be positioned within the socket; and a fastener that is configured to secure the ball within the socket, thereby attaching the ball stud to the shear tie.