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© Textechno Germanywww.textechno.com
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Dr. Stefan Fliescher
–
reTHINK Travelling Conference
“CFRP – Recycling and Sustainability”
Textechno –
Testing Solutions for the
Carbon Fibre Industry
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© Textechno Germanywww.textechno.com
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About Textechno Herbert Stein GmbH & Co. KG
Founder: Herbert Stein
Textechno’s Headquarter in Germany Lenzing Instruments in Austria
Founded in 1949 in Mönchengladbach, Germany
Family business, operating world-wide
Since the 1960ies market- and technology leader in
testing instruments for man-made fibres and yarns
In 2004 Textechno founded Lenzing Instruments in
Austria as specialist for online testing equipment
Since 2010 additional focus on testing solutions for
composite materials
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Textechno: 100% Made in Germany
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FAVIMAT+ Single Fibre Testing
Vibroscopic
head
Situation
Precise determination of modulus and breaking stress
of CFs is also possible on single filaments
Requires precise determination of the cross-section
per filament
Microscopic determination of
cross-section is time-consuming
and cumbersome
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FAVIMAT+ Single Fibre Testing
Vibroscopic
head
Approach
Integrate measurement of cross
section and breaking force into
one device: FAVIMAT+
Speed up the test with an
automatic single-fibre feeding
device: ROBOT 2
Use vibroscopic method to
determine cross section
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FAVIMAT+ Cross Section from Vibroscopic Method
Vibroscopic
head
Search the resonance frequency 𝑓 of the fibre
Given a know tension 𝐹, gauge length 𝐿and density of the fibre 𝜌 the cross section 𝐴 is calculated as:
𝐴 =𝐹
4𝜌𝐿2𝑓2
Jaws of
FAVIMAT+
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FAVIMAT+ Determination of Modulus
Precise determination of modulus as
derivative of the stress-elongation diagram
Here: Modulus = 275 GPa
Example: 20 tested Carbon Fibres
Force is translated to stress using the individual fibre cross sections
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Fast Fibre Diameter Distribution:
Situation
Diameter distribution is important e.g. to check homogeneity of rovings
Regular microscopic determination is cumbersome and time-consuming
Even with FAVIMAT+ limited statistics
Approach
Cut fibres into short sections
Dissolve and disperse in water
Scan with microscopic camera and
high-speed image analysis
Equipment developed and produced in Australia
Measures up to 20.000 fibres per minute
Fast and easy to use
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Fast Fibre Diameter Distribution:
Approach
Cut fibres into short sections
Dissolve and disperse in water
Scan with microscopic camera and
high-speed image analysis
Equipment developed and produced in Australia
Measures up to 20.000 fibres per minute
Fast and easy to use
Example: Distribution within a CF roving
Measured: 10000 fibres
Mean diameter: 5.8 µm
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FIMATEST: Fibre-Matrix Adhesion Testing
Performance of composites:
Strongly depends on fibre-matrix
adhesion, influenced by:
surface structure
sizing of the fibre
the matrix material
Macroscopic tests (e.g. ILSS) have
limited precision due to large influence of
the operator
Up to now tests on micro-level are time
consuming and not commercially
available
A single CF composite:
A single
carbon
fibreEpoxy matrix
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FIMATEST: Fibre-Matrix Adhesion Testing
A single CF composite:
A single
carbon
fibreEpoxy matrix
Approach:
Pull-out tests based on single fibre
composites have been researched at IPF
Dresden for the past 20 years
Pull-out most versatile of all
micromechanical tests –
suited for all kinds of fibres and matrices
Make microscopic pull-out test into a
commercial system
Cooperation with IPF Dresden and
Faserinstitut Bremen (FIBRE) for
knowledge transfer and automation
Use FAVIMAT+ for pull-out tests AND
cross-section AND tensile properties
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FIMATEST: Fibre-Matrix Adhesion Testing
A pull-out testing device
as accessory to FAVIMAT+
FIMATEST consists of:
The FIMABOND
embedding station
FIMATEST has
won the JEC
WORLD
Innovation
Award 2016
Many important
measurements for
CF in one system
fibre-matrix adhesion
and diameter,
breaking strength,
modulus of fibres
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FIMATEST: Embedding Station FIMABOND
Insert a fibre into the FIMABOND
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FIMATEST: Embedding Station FIMABOND
Example:
Embedding a fibre in PP
Matrix is placed in an
aluminum crucible
Freely-programmable
heater (max. 400°C)
Adjustable embedding
speed and depth
Inert atmosphere possible
(flushing with nitrogen,
argon etc.)
As seen by FIMABOND (time lapse)
Melting
Embedding
Cooling
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FIMATEST: Embedding Station FIMABOND
Example:
Embedding a fibre in PP
Matrix is placed in an
aluminum crucible
Freely-programmable
heater (max. 400°C)
Adjustable embedding
speed and depth
Inert atmosphere possible
(flushing with nitrogen,
argon etc.)
As seen by FIMABOND (time lapse)
Melting
Embedding
Cooling
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© Textechno Germanywww.textechno.com
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FIMATEST: Embedding Station FIMABOND
Example:
Embedding a fibre in PP
Matrix is placed in an
aluminum crucible
Freely-programmable
heater (max. 400°C)
Adjustable embedding
speed and depth
Inert atmosphere possible
(flushing with nitrogen,
argon etc.)
As seen by FIMABOND (time lapse)
Melting
Embedding
Cooling
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FIMATEST: Pull-out Test in FAVIMAT+
As seen by FAVIMAT+
Direct clamping of the
fibre huge speed up
in comparison to
previous lab setup
Measure the force-
displacement curve
using FAVIMAT+’s
excellent force and path
resolution (1µN, 0.1µm)
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FIMATEST: Pull-out Test Evaluation
The FIMATEST analysis software
automatically determines the
relevant parameters from the
force-displacement curve…
…and calculates the sought-after
quantities 𝜏f, 𝜏app, 𝜏d and Gic
Fd
Fmax
Fb
le
E. Mäder
F
Example: Pull-out from a epoxy resin
𝜏d : Local interfacial shear strength – based on Fdabsolute measure of the fibre-to-matrix adhesion,
independent from friction,
corrected for deformation of fibre and matrix during the pull-out test
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FIMATEST: Pull-out Test Evaluation
Calculated parameters:
Apparent interfacial shear strength………….….τapp [MPa]
Local interfacial shear strength………………τd [MPa]
Interfacial frictional stress…………………….….τf [MPa]
Critical interfacial energy release rate…..…. Gic [J/m2]
Meaning of the most important parameters:
τapp : based on the maximum force Fmax.Good for a first relative comparison of the fibre-to-maxtrix adhesion
(influence of fibre-to-matrix friction)
τd : based on the debonding force Fd.Absolute measure of the fibre-to-matrix adhesion, independent from friction
and corrected for deformation of fibre and matrix during the pull-out test
Gic : Describes the energy required to debond the fibre per unit contact surface area.
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waviness
Situation:
Defects in fabric structure occur in draping and forming
and lead to bad performance of composite parts.
Classical drapability testing as for textile applications is
not suited for reinforcement fabrics
Picture-frame test is used, but not standardized,
not suited for other than 0/90° geometries,
no automatic/objective detection of defects.
Partners: SAERTEX, FIBRE Bremen, Schilgen
DRAPETEST: Drapability Testing
Typical defects during draping:
undulations and loops gaps
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Approach:
Cricular sample deformed by
reference body
Clamping mechanism with
computer-controlled pressure
holds back the sample
Force to deform the sample is
recorded
DRAPETEST: Drapability Testing
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Approach:
Cricular sample deformed by
reference body
Clamping mechanism with
computer-controlled pressure
holds back the sample
Force to deform the sample is
recorded
Defects are detected and
analyzed: Gaps, undulation,
loops, waves, wrinkles
DRAPETEST: Drapability Testing
DIN-SPEC 8100 established
since November 2015
Project has been introduced
to ISO committee
Example: Gaps in a NCF
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NOS 200: Fibre Orientation in Nonwovens
Situation
Strength of the nonwoven web is directly
connected to the fibre orientation
Fiber orientation along and across the
machine direction is crucial indicator for
strength, tenacity and working capacity
of the nonwoven
Demand for non-destructive and fast
control of the MD-CD ratio Approach
High-speed CCD camera and intense
LED light combined with real-time
image analysis
Continuous online feedback about
the present fibre orientation
Constant quality level with minimum
waste loss
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Features
Fully automatic tensile tests on up to 48 yarn
ends / packages
Linear-density range from 1 to 5000 tex
Patented force-reduction cams
Integrated twister for better force-distribution
between the filaments
Reliable and objective
No user influence on results
Sealed version and dust suction for save
operation with carbon fibres
STATIMAT 4U: Automatic Tensile Testing
Situation
Textechno is manufacturing automatic
tensile tester for more than 50 years
STATIMAT 4U latest evolutionary stage
for high-tenacity materials
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Summary
Textechno’s testing solutions for carbon fibres
Textechno offers in house
testing services
FAVIMAT+
mechanical
properties
DRAPETEST
drapability of
fabrics
NOS 200
fibre orientation
in nonwovens
STATIMAT 4U
automatic tensile testing
DIAMSCOPE
diameter- and
length distribution
FIMATEST
fibre-to-matrix
adhesion
fibre – yarn – fabric – composite
Methods apply to both CF and rCF
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Textechno: 100% Made in Germany