Predictive Shimming for Flexible Surfaces Using Finite Element Analysis
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Solution Overview
Problem
Current methods for predicting the shapes of shims to fill gaps between rigid and flexible surfaces are inaccurate due to changes in the flexible surface's shape during measurement and assembly, leading to increased time, cost, and effort in manufacturing, especially in applications like aircraft wing assembly.
Innovation Solution
An apparatus comprising a surface model generator and analyzer that predicts the final shape of the mated flexible surface using finite element analysis, allowing for the precise generation of filler members to fill the gaps within selected tolerances, reducing the need for rework and manual measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual measurements are taken using feeler gauges to determine shim dimensions, then the measurement process can be performed, but the shape of the flexible surface changes during measurement causing inaccuracies
Solution Approach 1:
The patent performs measurements and generates shim predictions before the flexible surface undergoes shape changes during assembly. By conducting laser scanning and gap analysis in advance, the system captures the initial surface geometry before deformation occurs, allowing accurate shim design based on pre-change conditions.
Solution Approach 2:
The patent creates digital surface models (point clouds) as copies of the physical flexible surface. These digital replicas preserve the original surface geometry without causing physical deformation, allowing multiple measurements and analyses to be performed on the copied data rather than the actual flexible surface.
2Productivity
If shims are manufactured based on initial surface scans, then shims can be produced in advance, but the flexible surface shape changes between scanning and assembly causing mismatch
Solution Approach 1:
The system performs surface scanning, gap analysis, and shim design in advance before assembly. By completing these operations preliminarily, the system enables off-site shim manufacturing while maintaining accuracy through compensation for surface deformation that will occur during the assembly process.
Solution Approach 2:
The patent applies preliminary anti-action by predicting and compensating for the expected shape changes of the flexible surface. The system calculates how the surface will deform during assembly and adjusts the shim design in advance to counteract these changes, ensuring accurate fit despite the anticipated deformation.
3Ease of operation
If the flexible surface is held using suction cups or retaining devices, then the surface can be positioned, but the surface shape changes when released or during attachment
Solution Approach 1:
The patent performs surface scanning and measurement while the flexible surface is in its supported, easy-to-position state using suction cups or retaining devices. The measurements are taken preliminarily before the surface is released and subjected to assembly forces that would cause shape changes.
Solution Approach 2:
The system predicts the shape changes that will occur when the flexible surface is released from support devices and during attachment. By calculating these anticipated deformations in advance, the system compensates for them in the shim design, effectively counteracting the harmful shape changes.
4Ease of manufacture
If shims are made using currently available predictive shimming methods, then shims can be generated, but they may not fill gaps within selected tolerances or fit into gaps
Solution Approach 1:
The patent creates accurate digital surface models (point clouds) of both rigid and flexible surfaces, then uses these digital copies to calculate precise gap geometries. This copying approach allows for accurate virtual fitting and shim design without physical trial and error.
Solution Approach 2:
The system incorporates parameters representing the flexible surface's mechanical properties and expected deformation characteristics into the gap analysis. By changing and adjusting these parameters to reflect real-world behavior, the system generates more accurate predictions of final gap geometry and required shim shapes.
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 approach enables the accurate prediction and manufacturing of shims off-site, reducing rework and the need for new shims during installation, thereby decreasing overall time, cost, and effort in the manufacturing process.
Implementation Method 1
The analyzer performs a structural analysis using the first surface model and the second surface model to identify a predicted final shape of the mated flexible surface
Data Source
AI summary
A method and apparatus for forming a number of filler members. The apparatus comprises a surface model generator and an analyzer. The surface model generator generates a first surface model of a surface and a second surface model of a flexible surface. The surface and the flexible surface are to be mated to form a mated surface and a mated flexible surface. The analyzer performs a structural analysis using the first surface model and the second surface model to identify a predicted final shape of the mated flexible surface. The predicted final shape of the mated flexible surface is used to form the number of filler members to fill a number of spaces between the mated surface and the mated flexible surface.