Bulkhead Shim Assembly for Curvilinear Panel Radial Alignment
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Solution Overview
Problem
Existing methods for assembling thin-walled curvilinear aircraft components to structural supports like bulkheads are inefficient and costly due to the need for precise shimming to avoid aerodynamic steps, which can lead to turbulent airflow and erosion.
Innovation Solution
A method involving preassembly measurements to calculate the average radial gap between components and support structures, followed by the application of prefabricated shims of specific thickness to ensure radial alignment and minimize aerodynamic steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If custom contoured shims are employed to achieve precise radial alignment, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies local quality by using constant thickness shims with varying radial positions rather than uniformly contoured shims. Each shim maintains a constant thickness but is positioned at a specific radial location to compensate for local gap variations, achieving precise radial alignment without the complexity of custom contoured shapes.
Solution Approach 2:
The patent segments the shim compensation function into multiple discrete constant-thickness shims positioned at different radial locations around the curvilinear component. Instead of using a single complex contoured shim, the solution divides the gap compensation into several simpler shim elements, each handling a specific radial position.
2Manufacturing precision
If custom contoured shims are fabricated to match complex gap variations, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent implements preliminary action by pre-calculating the required shim thicknesses and radial positions before assembly. The method measures radial gaps at multiple positions, calculates average values and deviations, and determines the specific constant-thickness shim specifications in advance, allowing for rapid assembly without time-consuming custom fabrication.
Solution Approach 2:
The patent changes the parameters of the shim system from custom contoured shapes to standardized constant-thickness shims with varying radial positions. This parameter transformation simplifies the shimming process by converting a complex geometric matching problem into a simpler measurement-calculation-assembly workflow.
3Object-affected harmful factors
If traditional shimming methods are used to achieve precise alignment, then aerodynamic quality is improved, but loss of time increases
Solution Approach 1:
The patent replaces the traditional mechanical trial-and-error shimming process with a measurement-calculation-determination system. Instead of physically fitting custom contoured shims through iterative adjustment, the method uses gap measurements, mathematical calculations of average values and deviations, and direct determination of shim specifications to achieve precise alignment in a single assembly step.
4Ease of manufacture
If prefabricated constant thickness shims are used instead of custom contoured shims, then ease of manufacture is improved, but manufacturing precision may worsen
Solution Approach 1:
The patent compensates for the simplicity of constant-thickness shims by introducing a radial position dimension. Instead of achieving precision through complex shim geometries, the method uses the radial positioning of multiple constant-thickness shims around the curvilinear component to accurately compensate for circumferential gap variations, adding a spatial arrangement dimension to the solution.
Data Source
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AI summary
A method of assembling thin-walled curvilinear components (16,12) to a bulkhead (14) offers a cost-effective, time-saving process of manufacture. Each component includes a faying edge configured to be aligned with respect to the other. A first component (16) and the bulkhead (14) are preassembled. In one approach, a second component (12) is clamped about the bulkhead (14) for a preassembly measurement of radial gaps between the faying edge of the second component (12) and the bulkhead (14). An average value of the radial gaps is calculated, and a specific shim thickness corresponding to the calculated average gap value is selected. The second component (12) is unclamped, and a plurality of shims (30), each having the selected thickness corresponding to the calculated average gap value, is applied about the bulkhead (14). The second component (12) is then permanently secured to the bulkhead (14) over the shims (30), with respective faying edges of the first and second components fixed in radial alignment with each other.