MATERIALS
FIBER-REINFORCED PLASTIC
SKZ
FIBER PLASTIC COMPOSITES IN RED LIGHT -
EFFICIENTLY TESTED WITH SHEAROGRAPHY
Fiber-reinforced plastic composite
components can be tested contactlessly and
flexibly with Lock-In Shearography, which is
currently being tested at SKZ.
There, the advantages and possibilities
of this non-destructive testing method,
which has hitherto mainly been used on a
laboratory scale, have been investigated
and developed with regard to practical
requirements.
In conventional shearography, the
components to be examined are irradiated
by means of a widened laser light to detect
material defects and both in a z. B. slightly
thermally loaded as well as an unloaded
condition of the shearography camera
added.
By a digital comparison of the recorded
images, defects such as foreign material
inclusions or material separations can
then be detected. This testing technique
has hitherto been established in the field
of elastomers, for example in tire testing.
In rigid materials such as fiber-reinforced
plastics, however, it is in many cases too
insensitive.
One solution to this problem is the transfer
of the lock-in technique, a thermo-mature
method, to shearography. The component is
continuously imaged during a periodic load.
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Subsequently, the measured data are
specially evaluated with regard to the
excitation frequency. In addition to an
increase in the signal-to-noise ratio, the
depth of defects can be recorded by using
several lock-in frequencies.
Due to long computing times, this method
has in the past been limited to use in
the laboratory. In order to enable use in
industrial component testing, which often
requires strict time requirements, the
SKZ has optimized the necessary image
processing and accelerated it many times
over by using parallel algorithms.
The potentials of lock-in shearography
thus present are currently still being
exploited on various fiber-reinforced plastic
composite components, e.g. B. with practical
delaminations or impact damage tested.
Following the current research project
(01.03.2016 to 31.08.2018), funded by the
German Federation of Industrial Research
Associations (AiF) within the framework of
the program for the promotion of industrial
joint research (IGF) of the Federal Ministry
for Economic Affairs and Energy (BMWi) (IGF
Project No. 19063 N), is a continuation of the
cooperation between SKZ and the Company
isi-sys GmbH, Kassel, planned for the further
industrialization and commercialization of
the researched techniques.
Interested companies can have their
components tested free of charge as part
of public projects at the SKZ in order
to demonstrate the suitability of the
method and to establish it in the industry.
planned for further industrialization and
commercialization of the researched
techniques.
Interested companies can have their
components tested free of charge as part
of public projects at the SKZ in order
to demonstrate the suitability of the
method and to establish it in the industry.
planned for further industrialization and
commercialization of the researched
techniques. Interested companies can have
their components tested free of charge as
part of public projects at the SKZ in order to
demonstrate the suitability of the method
and to establish it in the industry.
The SKZ is a member of the Zuse
community. It is a network of independent,
industry-related research institutes with
the aim of improving the performance and
competitiveness of industry, especially SMEs,
through innovation and networking.
www.skz.de