Printed strain gauges for aircraft load detection using ... · IFAM activities in Clean Sky using...

© Fraunhofer IFAMContact: Dr. Ingo Wirth, Tel.: +49 421-2246-232 Dipl.-Ing. Elmar Taubenrauch, Tel.: [email protected] [email protected]

Printed strain gauges for aircraft load detection using Aerosol Jet® printing Aerosol Jet® User Group Meeting

Dipl.-Ing. Elmar Taubenrauch / Dr. Ingo Wirth


Printed strain gauges for aircraft load detection using Aerosol Jet® printing

Introduction Fraunhofer IFAM

INKtelligent printing® at Fraunhofer IFAM

Aerosol Jet® printing in EU-Project CLEAN SKY

INKtelligent® printer at Fraunhofer IFAM


IntroductionFraunhofer-Institute for Manufacturing Technology and Advanced Materials - IFAM

Departments Shaping and Functional

Materials Adhesive Bonding

Technology and Surfaces

Locations in Bremen andDresden

Project groups in Oldenburgand Stade

478 employees

Overall budget 2010:35.3 million €


IntroductionPrinting activites at Fraunhofer IFAM

Business Areas Competencies

Automotive / Aerospace Process and Material Development /Functional Integration

Microsystems / Electronic Industry

Sensor Systems

Energy Management Energy Harvesting

Medical Engineering / Nano Technology

Medical Diagnostics / Nanoparticle Systems

Manufacturing Systems Engineering

Shaping and ProductionTechnologies


Design & Layout

Material screening

Printing process

Characterisation

Ink formulation

INKtelligent printing®

Technology platform



Deposition technologies at Fraunhofer IFAM

Screen printing

Ink-Jet-printing: Dimatix, Voxeljet, Microdrop

Aerosol Jet®, INKtelligent® printer

Dispensing machine for high viscous composites

Rapid Manufacturing: 3D printing, selective laser sintering



Application areas

Automotive

Aerospace

Robot technology

Medical Technology

Microsystem Technology

Electronic Industry

Sensor Technology

Medical Diagnostics

Solar Technology

Functionalized Textiles and Composites

Miniaturization and Integration

New deposition materials


IFAM activities in Clean Sky using Aerosol Jet® printing technology

Development of load sensors to support active load control

Clean Sky is the largest European aeronautical research programme(~ 1.6 billion €) devoted to environment and places Europe at theforefront of the greening of aviation

Clean Sky - Structural Health Monitoring (SHM)Load sensor evaluation


Clean Sky - Structural Health Monitoring (SHM)Motivation

© C. Bockenheimer, Airbus Deutschland GmbH: SMIST – Structural Monitoring with Advanced Integrated Sensor Technologies – Aeronautic Days, Vienna, 19.-21.06.2006


Design of strain gauges on Aircraft wing

Objective: Optimal Signal-Noise-Ratio

Product / Process:

Load Control

Signal Factor:Piezo–resistive effect

Control Factor:e.g. position, material, …

Noise Factor:e.g. temperature influence, …

Response:Change in el. resistivity

Clean Sky - Structural Health Monitoring (SHM)Motivation


FE-Analysis

Calculation of dislocation function and strain components:

Optimal position and orientation for strain gauge

Dislocation function

Mechanical forces (uplift)

Strain in z direction

Clean Sky - Structural Health Monitoring (SHM)Robust Design


Sensor material requirements based on strain demands

FE stress analysis: strain gauges under mechanical load: Pt - material

FE stress analysis: strain gauges under mechanical load: Ag - material

Clean Sky - Structural Health Monitoring (SHM)Robust Design


Wheatstone full bridge

strain gauge printed on substratewhich is fixed in a tensile tester

resistance Rx = additional resistancefor bridge balancing

measuring setup parameters:

room temperature tensile and compressive stress testing frequency 25 Hz 105 cycles

Clean Sky - Structural Health Monitoring (SHM)Aerosol Jet® printed strain gauges

5 mm5 mm


Sensor test equipment

dynamic measure-ments up to 50 Hz

maximum stress~ 20 kN

Clean Sky - Structural Health Monitoring (SHM)Sensor evaluation


Measurement setup


printed silver strain gauge

temperature compensation

VISHAYfoil strain gauge (reference)


Clean Sky - Structural Health Monitoring (SHM)

test no sensor material / substrate

tensile stress μstrain [μm/m]

compressive stress μstrain [μm/m]

cycles frequency

1 Ag on Al 50 50 1.000 25 Hz

2 Ag on Al 250 125 1.000 25 Hz

3 Ag on Al 550 125 1.000 25 Hz

4 Ag on Al 1.100 125 1.000 25 Hz


Clean Sky - Structural Health Monitoring (SHM)test no sensor material /

substratetensile stress μstrain [μm/m]


cycles frequency

5 Ag on Al 1.100 125 5.000.000 25 Hz


Clean Sky - Structural Health Monitoring (SHM)

test no sensor material / substrate

tensile stress μstrain [μm/m]


cycles frequency

6 Ag on Al 1.100 125 100.000 25 Hz

constant signal of printed Ag strain gauges → no cracks inprintedstructure


Clean Sky - Structural Health Monitoring (SHM)Printing of Ag strain gauges on Al specimen


Clean Sky - Structural Health Monitoring (SHM)Printed Ag strain gauges on Al specimen

Oven sintering of printed strain gauges on Al specimen


Time dependence of electrical resistance during oven sintering process at T = 120 °C

Clean Sky - Structural Health Monitoring (SHM)Printed strain gauges on Al specimen


Clean Sky - Structural Health Monitoring (SHM)Printed Ag strain gauges on Al specimen

Printed strain gauges with temperature compensation


Aerosol printed strain gauges for active load control

Development of Ag, Cu/Ni and other nanodispersed inks

Application of printed strain gauges on several parts and differentsurfaces

Development and investigation for sensorial applications



Fraunhofer IFAM – Functional StructuresINKtelligent® Printer


Fraunhofer IFAM - Functional StructuresINKtelligent® PrinterMotivation and requirementsVariable substrate sizes

Prototyping with original customer parts orcomplete assemblies

Substrate height ≥ 200mm

max. substrate width 450mm

Variability in fixing or clamping thecomponents on the machine table

Possibility of inline-production, goodaccessibility

Usage of specific work piece carriers

Automatic substrate feeding by an industryroboter planned


Fraunhofer IFAM - Functional StructuresINKtelligent® PrinterMotivationFull functionality in 3D-Printing

printing on curved surfaces or on differentplanes with different printing methods

exact measuring of customer parts with newgeometry


Fraunhofer IFAM - Functional StructuresINKtelligent® Printer

mechanical base – small CNC milling machine

high mechanical flexibility

enabling technology for many rapid prototypingmethods

sufficient accuracy and good stiffness in all axes

variable software and controlling system

easy to use

economical design



mechanical base – small CNC milling machine

IFAM INKtelligent® Printer - Technical Data

stepper motors (X/Y/Z) 4A 300Ncm

repeat accuracy ≤ 15μm

max. failure in positioning ≤ 8μm

axis length (X/Y/Z) 850mm / 450mm / 270mm

guidings ball screw / ball rail systems in all axis

machine table size 1350mm x 640mm

maximal component height 280mm

linear resolution (X/Y/Z) 3,125μm

max. movement speed (X/Y/Z) 60mm/s



Aerosol headfixing port Shutter

Pneumatic Cylinder

Process View Camera

Measuring Sensor

Optomec Aerosol Jet® - standard printing head



Aerosol headfixing port Shutter

Pneumatic Cylinder

Process View Camera

Measuring Sensor


same nozzle position for different print-heads

process view camera

fixed shutter



Aerosol Jet® - Closely coupled print head assembly (CCPA)

water cooled thermal isolation bracket



Optomec Aerosol Jet® - Printing on 3D-Surfaces

measuring sensor, fixed on a separate Z-support



other functions: dispensing with rotary valve

volumetric extrusion of highly viscous materialby a disposable feed screw, easy to change/clean

motor

materialdepot

spindle

nozzle



other functions: spraying-valve

homogeneous spaying jet for surface coating

material ‐depot

spray jet

needle

compressed air

piston

spring

compressed air


Aerosol Jet® printing at Fraunhofer IFAMInterdisziplinary team

Prof. Dr.-Ing. Matthias Busse

Cindy Behrens

Ass. Andreas Burblies

Dr.-Ing. Dirk Godlinski

Dipl.-Ing. Arne Haberkorn

Dr. Róbert Kun

Dr.-Ing. Dirk Lehmhus

Dipl.-Ing. Marcus Maiwald

Dr. Edit Kunné Pál

Dipl.-Mat. Natalia Reichert

Tim Rusch

Dipl.-Ing. Torben Seemann

Dipl.-Ing. Elmar Taubenrauch

Dr. Ingo Wirth

Dipl.-Ing. Christian Werner

Gert-M. Wöbken

Dr. Volker Zöllmer

Thank youfor your attention!

Printed strain gauges for aircraft load detection using ... · IFAM activities in Clean Sky using...

Documents

Transcript of Printed strain gauges for aircraft load detection using ... · IFAM activities in Clean Sky using...