stirscan structures · ng non-destructive testing (ndt) methods. friction-stir welding (fsw) is a...
TRANSCRIPT
The research leading to these results has received
funding from the European Union Seventh Framework
Programme [FP7/2007-2013] under grant agreement
no 315436.
Copyright StirScan © 2013. All Rights Reserved.
Detection of kissing bonds in
friction stir
welds in aero
structures
StirScan
Contact
Project
participants
Project co-ordinator
Verm
on SA
www.verm
on.com
SMEs
Research
Organisations
Theta Technologies
www.thetatech.co.uk
Innora Ltd
www.innora.gr
ABIS sp. z o.o. sp.k.
www.st-ji.com
Saint Jean Wheels AS
TWI Ltd
www.twi.co.uk
FP7: The future of European Union research policy
For all technical enquiries please feel free to contact:
Verm
on S.A.
180 rue du Général Renault
37038 Tours Cedex 1, France
e-m
ail: contact@
verm
on.com
More details and news available at project’s website:
www.stirscan.eu
www.abis.krakow.pl
End-User
Katholieke Universiteit
Leuven
VZLÚ A.S.
www.kuleuven.be
www.vzlu.cz
The b
ackgro
und
The n
eed
The c
oopera
tion
It might happen that two surfaces have been only
partially bonded or are disbonded but touching or in
very close proximity. This is refered to as a „Kissing
Bond”, and is a concern with FSW as such features
reduce fatigue performance of joints, and are very
difficult to detect or accurately size using existing Non-
destructive testing (NDT) methods.
Friction-Stir Welding (FSW) is a solid-state joining
process, developed and proved in 1991 by The
Welding Institute UK. FSW uses a third body tool to
join two faying surfaces. It has many economic,
environmental
and
safety
advantages
over
conventional welding, as well as it is capable of
overcoming some lim
itations of conventional fusion
welding techniques. It is used as a high-performance
joining technique for aluminium alloys, which offers
excellent joint performance and reproducibility.
This is of significant
interest
to
sectors
such as aerospace
and automobile, where
fatigue performance is
particularly crucial.
Friction-Stir Welding, when compared with commonly
used riveting joining methods used for aerospace
structures, contributes to increased joining speed,
higher stress tolerance and longer service life. In
addition, the application of FSW m
ethods have been
shown to save up to 10% weight on typical airframe
structures, as well as reducing working hours by 40%.
Since fatigue performance is particularly crucial, while
there is not a reliable method of detecting kissing
bonds, the use of FSW (and associated benefits) is
restricted only to non-safety critical components.
Effective detection of kissing bonds would open up a
much wider range of applications, including safety-
critical subcomponents.
The
StirS
can
pro
ject
will
develo
p
a
new
N
DT
meth
odolo
gy to
enable
th
e dete
ction of
kis
sin
g
bond d
efe
cts
belo
w 0
.3 m
m in length
in a
ero
space
com
ponents
e.g
. fu
sela
ge a
nd w
ing s
kin
s (to
p a
nd
bottom
).
In order to develop the NDT inspection techniques,
a set of samples will be manufactured and
categorized into FSW without and with defects.
For
this – a set
of
aluminium wheels will be
sourced and supplied by
the end user (St.Jean).
The wheels are used in
the automobile industry
and have curved profile.
A number
of flat FSW plates with different
thicknesses,
which
are
representative
of
components used in the aerospace industry, will
also be manufactured and provided by TWI.
Key, innovative elements required in order to
develop the StirScan system are:
Combination of non-linear ultrasonic technique
(NLUT) and a high frequency ultrasonic technique
(HFUT).
Development of a prototype scanner with an
incorporated probe holder
to enable rapid
inspection of FSW.
Development of a graphic user-interface (GUI)
and interpretation software; enabling simple use,
interpretation and post-processing of acquired
data.
Generation of a full set of test data, precisely
determining and demonstrating the ability of the
StirScan system.