Predictive Shimmed Assembly for Composite Joint Gap Elimination

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Solution Overview

Problem

Existing methods for assembling composite parts using fillers or shims are iterative, destructive, and strain the composite joints, leading to reduced strength and potential delamination due to gaps between composite materials and supporting structures.

Innovation Solution

A method and system that uses nondestructive inspection to generate data for shaping a filler or shim with a computer numerical controlled manufacturing device, ensuring a precise fit between the composite substructure and support structure, reducing gaps and strain during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If an iterative process is used to shape the filler or shim by mounting, inspecting, and adjusting, then the fit between the filler and composite part can be improved, but the process time increases and the filler/composite part may be damaged requiring replacement

Engineering Contradiction:
Improvefit between filler and composite partVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention performs the shaping action in advance by creating a digital model of the composite part surface and using it to manufacture a precisely fitted filler or shim before final assembly. This eliminates the need for iterative mounting and adjusting, as the filler is pre-shaped to match the composite part surface exactly, thereby reducing assembly time while maintaining high precision fit.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention creates a digital copy or model of the composite part mating surface using scanning technology. This digital model is then used to generate the corresponding filler or shim geometry through computer-aided design and manufacturing. By copying the surface geometry digitally, the invention achieves precise fit without physical iterative adjustments, eliminating time loss and damage risks associated with traditional methods.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If adhesive is used to bridge gaps between composite material and supporting structure, then the gaps can be filled, but the composite joint becomes strained leading to delamination or reduced joint strength

Engineering Contradiction:
Improvegap eliminationVSAvoidjoint strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The invention replaces the mechanical/adhesive bonding system with a precision geometric fit system. By using a filler or shim that is precisely shaped to match the composite part surface and support structure, the gaps are eliminated through geometric compatibility rather than adhesive filling. This prevents strain on the composite joint, avoiding delamination and maintaining joint strength, as the load is distributed through the rigid filler geometry rather than strained adhesive bonds.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If traditional inspection methods are used during iterative shaping, then the fit can be monitored, but the inspection process is destructive to the filler and/or composite part

Engineering Contradiction:
Improvesurface shape accuracyVSAvoidintegrity of filler and composite part
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention creates a non-destructive digital copy of the composite part mating surface through scanning technology. This digital model preserves the complete surface geometry information without any physical contact or damage to the composite part. The digital model is then used to manufacture the filler with precise fit, eliminating the need for destructive physical inspection methods while maintaining surface shape accuracy.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The invention replaces physical/mechanical inspection methods with optical or electromagnetic scanning systems. These non-contact scanning technologies capture the composite part surface geometry by emitting and detecting signals (such as light or electromagnetic waves) without touching the part, thereby avoiding any damage to the filler or composite part while achieving high measurement precision for surface shape.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reduces the time required for assembly, minimizes the risk of strength reduction, and enhances the quality of composite laminate joints by allowing for a precise, non-destructive shaping of shims that adapt to the substructure's surface, thereby improving joint strength and reducing the likelihood of delamination.

Implementation Method 1

emitting a signal from an inspection system proximate a mating surface of the substructure, detecting a reflection of the signal with the inspection system

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

shaping a filler structure with a computer numerical controlled shaping device using the filler dimension data

Methodology Applied
Scientific EffectComputer numerical control machining:

Implementation Method 3

adhering a first surface of the filler structure to the mating surface of the substructure

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

forming a substructure at least partially composed of an uncured resin material, curing the shimmed substructure subassembly

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Data Source

PatentEP4036782A1Methods and systems for forming a shimmed assembly using predictive shimming
Publication Date: 2022.08.03 THE BOEING CO
  • EP4036782A1 patent drawingFigure 1
  • EP4036782A1 patent drawingFigure 2A
  • EP4036782A1 patent drawingFigure 2B

AI summary

A method of manufacturing and mounting a shim is disclosed, comprising: non-destructively inspecting a mating surface of the substructure using a scanning device; comprising an emitter and a detector; generating with the scanning device a data set representing a shape of the mating surface; generating a 3D model of the shim, wherein a first surface of the shim is based on the data set; manufacturing the shim with a computer numerical controlled manufacturing device, the shim having a first surface shaped based on the 3D model and a second surface substantially opposite the first surface based on a predicted shape of a support structure; applying the shim to the substructure such that the first surface engages the mating surface to form a sub-assembly; adhering a support structure to the second surface of the shim, and curing the sub-assembly.