Direct Write Structural Elements for Aerodynamic Flow Control

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Solution Overview

Problem

Conventional methods for introducing irregularities on aerodynamic surfaces in wind tunnels, such as vortex generators and surface roughening, are unreliable, inaccurate, and cause flow disturbances due to the use of adhesives and bonding techniques, which are difficult to reproduce and interfere with fluid flow.

Innovation Solution

A method of fabricating three-dimensional structural elements on a surface by depositing and curing material layers, using techniques like Direct Write to form protrusions that modify fluid flow, optionally using passive or active materials and machining for enhanced accuracy and functionality, avoiding the need for adhesives and minimizing flow interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesive bonding techniques are used to attach elements to the aerodynamic surface, then the elements can be securely fixed, but flow disturbances are caused by the adhesive or base surface

Engineering Contradiction:
Improvebonding reliabilityVSAvoidflow disturbance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the adhesive bonding step entirely from the process. Elements are created directly on the aerodynamic surface through deposition and curing, eliminating the adhesive layer and base surface that cause flow disturbances. This extraction of the harmful bonding step resolves the contradiction by achieving secure attachment without flow interference.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/chemical bonding system (adhesive and base surface) with a direct material deposition and curing system. Instead of attaching pre-formed elements with adhesive, the elements are formed in situ through controlled material deposition followed by curing, substituting the bonding mechanism with a direct formation process that eliminates flow disturbances.

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

2Productivity

If elements are introduced in an ad-hoc manner using conventional bonding techniques, then quick attachment is achieved, but accuracy and reproducibility deteriorate

Engineering Contradiction:
Improveattachment speedVSAvoidelement placement accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs preliminary action by depositing material layers in precise predetermined patterns before curing. The material is deposited according to pre-programmed coordinates and geometries, ensuring accurate element placement and shape definition before the curing step locks the structure in place. This preliminary precise deposition resolves the contradiction by establishing accuracy before finalization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses periodic action through layer-by-layer deposition and curing cycles. Each layer is deposited, cured, and then the next layer is added, creating a controlled iterative process that builds elements with high precision. This periodic deposition-curing sequence allows for accurate shape control and reproducible element formation, resolving the accuracy-reproducibility issue.

Inventive Principle:
Principle #19Periodic action

3Reliability

If base surfaces are provided for each element to enable adhesive bonding, then secure attachment is achieved, but device complexity and flow interference increase

Engineering Contradiction:
Improveattachment securityVSAvoidelement structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the element formation and attachment steps into a single integrated process. Instead of separately providing base surfaces and then bonding elements, the elements are formed directly on the aerodynamic surface through deposition and curing. This merging eliminates the need for separate base surfaces and adhesive layers, reducing structural complexity while maintaining secure attachment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and removes the base surface component from the element structure. By forming elements directly on the aerodynamic surface without requiring separate base surfaces for adhesive attachment, the patent eliminates this unnecessary structural element, thereby reducing device complexity and removing a potential source of flow interference.

Inventive Principle:
Principle #2Taking out (Extraction)

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 allows for precise and reliable creation of structural elements that accurately simulate large-scale phenomena without flow disturbances, enabling more accurate wind tunnel testing and potential integration of sensors or actuators for enhanced control surfaces.

Implementation Method 1

curing the deposited material

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Implementation Method 2

partially curing the, or each, layer of material by locally applying heat or radiation thereto

Methodology Applied
Scientific EffectHeat curing: Heating

Implementation Method 3

forming a said element by depositing material on the surface; depositing one or more layers of material on the surface

Methodology Applied
Scientific EffectMaterial deposition: Deposition (physical)

Data Source

PatentEP2223072B1Improvements relating to methods of fabricating structural elements
Publication Date: 2018.09.05 BAE SYSTEMS PLC
  • EP2223072B1 patent drawingFigure 1~2
  • EP2223072B1 patent drawingFigure 3~4
  • EP2223072B1 patent drawingFigure 5

AI summary

A method of fabricating structural elements on the surface of a component is provided. The structural elements are configured to modify flow of a fluid passing over the surface. Conveniently, the fabrication is performed using a Direct Write technique. A three dimensional element 100 is formed by depositing material on the surface 20, and subsequently curing the deposited material.