Aircraft Component Assembly Using Solid and Liquid Shims
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Solution Overview
Problem
The assembly of aircraft components, such as wing skins to rib feet, faces challenges in achieving precise tolerances without distorting the external profile or introducing internal stresses, particularly when using shims, as existing methods require time-consuming application of liquid shims before assembly or alter the underlying structure.
Innovation Solution
A method involving the application of a solid shim between the parts to be assembled, followed by the introduction of a liquid shim through passageways in one part, allowing for assembly without risk of premature curing, and subsequent curing between the solid shim and the part, ensuring a precise fit without distorting the external profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid shim is applied before assembly, then precise fit is achieved, but assembly time is constrained due to curing risk
Solution Approach 1:
The shim is divided into two distinct parts: a solid shim that provides immediate structural support and positioning, and a liquid shim that fills remaining gaps and provides precise fit. This segmentation allows the solid shim to be applied first for rough positioning, then the liquid shim is introduced through passageways to fill voids, eliminating the need to choose between precision and time constraints
Solution Approach 2:
The solid shim is applied in advance to establish proper positioning and alignment of the parts before the liquid shim is introduced. This preliminary action creates a stable framework that allows assembly to proceed without rushing, while the liquid shim is subsequently added through passageways to achieve precise fit without the time pressure of premature curing
2Manufacturing precision
If wing skin is deformed to eliminate spacings, then assembly tolerance is achieved, but external profile distortion occurs
Solution Approach 1:
The shim system acts as an intermediary element between the wing skin and rib feet, providing the necessary spacing adjustment without requiring deformation of the wing skin itself. The solid and liquid shims together fill gaps and accommodate tolerance variations, allowing the wing skin to maintain its original aerodynamic profile while achieving precise assembly tolerance
3Manufacturing precision
If material is added to wing skin, then assembly tolerance is achieved, but structural stress is introduced
Solution Approach 1:
The shim system serves as a mediator that provides the necessary material compensation for tolerance gaps without adding material directly to the wing skin structure. By placing shims at the interface between the wing skin and rib feet, the solution achieves assembly tolerance while avoiding the introduction of additional internal stresses into the wing-box structure
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 method enables efficient and precise assembly of aircraft components by allowing for extended assembly time without curing the liquid shim, ensuring a strong and aerodynamically optimal connection while minimizing structural stress and maintaining the external profile integrity.
Implementation Method 1
introducing a liquid shim through the first part into a region between the first part and the solid shim
Implementation Method 2
a liquid shim (a substance that is applied as a liquid but cures to a solid)
Data Source
AI summary
A method is provided for preparing a first part for assembly to form an aircraft component, by applying a shim to a first surface of the first part, the method comprising the steps of placing the first surface of the part adjacent to a second surface of a second part, inserting a solid shim into a gap between the first and second surfaces and holding the shim in the inserted position, and subsequently introducing a liquid shim through the first part into a region between the first part and the solid shim.