<s>
A	O
strain	B-Algorithm
gauge	I-Algorithm
(	O
also	O
spelled	O
strain	B-Algorithm
gage	I-Algorithm
)	O
is	O
a	O
device	O
used	O
to	O
measure	O
strain	O
on	O
an	O
object	O
.	O
</s>
<s>
Invented	O
by	O
Edward	O
E	O
.	O
Simmons	O
and	O
Arthur	O
C	O
.	O
Ruge	O
in	O
1938	O
,	O
the	O
most	O
common	O
type	O
of	O
strain	B-Algorithm
gauge	I-Algorithm
consists	O
of	O
an	O
insulating	O
flexible	O
backing	O
which	O
supports	O
a	O
metallic	O
foil	O
pattern	O
.	O
</s>
<s>
Edward	O
E	O
.	O
Simmons	O
and	O
Professor	O
Arthur	O
C	O
.	O
Ruge	O
independently	O
invented	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
.	O
</s>
<s>
The	O
development	O
of	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
was	O
essentially	O
just	O
a	O
byproduct	O
of	O
other	O
research	O
projects	O
.	O
</s>
<s>
Arthur	O
C	O
.	O
Ruge	O
realized	O
the	O
commercial	O
utility	O
of	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
.	O
</s>
<s>
The	O
strain	B-Algorithm
gauge	I-Algorithm
applications	O
were	O
quickly	O
gaining	O
traction	O
as	O
they	O
served	O
to	O
indirectly	O
detect	O
all	O
other	O
quantities	O
that	O
induce	O
strain	O
.	O
</s>
<s>
A	O
strain	B-Algorithm
gauge	I-Algorithm
takes	O
advantage	O
of	O
the	O
physical	O
property	O
of	O
electrical	O
conductance	O
and	O
its	O
dependence	O
on	O
the	O
conductor	O
's	O
geometry	O
.	O
</s>
<s>
From	O
the	O
measured	O
electrical	O
resistance	O
of	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
,	O
the	O
amount	O
of	O
induced	O
stress	O
may	O
be	O
inferred	O
.	O
</s>
<s>
A	O
typical	O
strain	B-Algorithm
gauge	I-Algorithm
arranges	O
a	O
long	O
,	O
thin	O
conductive	O
strip	O
in	O
a	O
zig-zag	O
pattern	O
of	O
parallel	O
lines	O
.	O
</s>
<s>
Foil	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
used	O
in	O
many	O
situations	O
.	O
</s>
<s>
In	O
most	O
cases	O
the	O
orientation	O
of	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
is	O
significant	O
.	O
</s>
<s>
Gauges	O
attached	O
to	O
a	O
load	B-Algorithm
cell	I-Algorithm
would	O
normally	O
be	O
expected	O
to	O
remain	O
stable	O
over	O
a	O
period	O
of	O
years	O
,	O
if	O
not	O
decades	O
;	O
while	O
those	O
used	O
to	O
measure	O
response	O
in	O
a	O
dynamic	O
experiment	O
may	O
only	O
need	O
to	O
remain	O
attached	O
to	O
the	O
object	O
for	O
a	O
few	O
days	O
,	O
be	O
energized	O
for	O
less	O
than	O
an	O
hour	O
,	O
and	O
operate	O
for	O
less	O
than	O
a	O
second	O
.	O
</s>
<s>
Strain	B-Algorithm
gauges	I-Algorithm
are	O
attached	O
to	O
the	O
substrate	O
with	O
a	O
special	O
glue	O
.	O
</s>
<s>
The	O
preparation	O
of	O
the	O
surface	O
where	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
is	O
to	O
be	O
glued	O
is	O
of	O
the	O
utmost	O
importance	O
.	O
</s>
<s>
with	O
very	O
fine	O
sand	O
paper	O
)	O
,	O
deoiled	O
with	O
solvents	O
,	O
the	O
solvent	O
traces	O
must	O
then	O
be	O
removed	O
and	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
must	O
be	O
glued	O
immediately	O
after	O
this	O
to	O
avoid	O
oxidation	O
or	O
pollution	O
of	O
the	O
prepared	O
area	O
.	O
</s>
<s>
If	O
these	O
steps	O
are	O
not	O
followed	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
binding	O
to	O
the	O
surface	O
may	O
be	O
unreliable	O
and	O
unpredictable	O
measurement	O
errors	O
may	O
be	O
generated	O
.	O
</s>
<s>
Strain	B-Algorithm
gauge	I-Algorithm
based	O
technology	O
is	O
used	O
commonly	O
in	O
the	O
manufacture	O
of	O
pressure	O
sensors	O
.	O
</s>
<s>
Most	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
made	O
from	O
a	O
constantan	O
alloy	O
.	O
</s>
<s>
Various	O
constantan	O
alloys	O
and	O
Karma	O
alloys	O
have	O
been	O
designed	O
so	O
that	O
the	O
temperature	O
effects	O
on	O
the	O
resistance	O
of	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
itself	O
largely	O
cancel	O
out	O
the	O
resistance	O
change	O
of	O
the	O
gauge	O
due	O
to	O
the	O
thermal	O
expansion	O
of	O
the	O
object	O
under	O
test	O
.	O
</s>
<s>
Strain	B-Algorithm
gauges	I-Algorithm
that	O
are	O
not	O
self-temperature-compensated	O
(	O
such	O
as	O
isoelastic	O
alloy	O
)	O
can	O
be	O
temperature	O
compensated	O
by	O
use	O
of	O
the	O
dummy	O
gauge	O
technique	O
.	O
</s>
<s>
A	O
dummy	O
gauge	O
(	O
identical	O
to	O
the	O
active	O
strain	B-Algorithm
gauge	I-Algorithm
)	O
is	O
installed	O
on	O
an	O
unstrained	O
sample	O
of	O
the	O
same	O
material	O
as	O
the	O
test	O
specimen	O
.	O
</s>
<s>
This	O
will	O
cause	O
strain	B-Algorithm
gauges	I-Algorithm
to	O
register	O
a	O
deformation	O
in	O
the	O
material	O
which	O
will	O
make	O
it	O
change	O
signal	O
.	O
</s>
<s>
To	O
prevent	O
this	O
from	O
happening	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
made	O
so	O
they	O
will	O
compensate	O
this	O
change	O
due	O
to	O
temperature	O
.	O
</s>
<s>
Dependent	O
on	O
the	O
material	O
of	O
the	O
surface	O
where	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
is	O
assembled	O
on	O
,	O
a	O
different	O
expansion	O
can	O
be	O
measured	O
.	O
</s>
<s>
In	O
any	O
case	O
it	O
is	O
a	O
good	O
engineering	O
practice	O
to	O
keep	O
the	O
Wheatstone	O
bridge	O
voltage	O
drive	O
low	O
enough	O
to	O
avoid	O
the	O
self	O
heating	O
of	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
.	O
</s>
<s>
The	O
self	O
heating	O
of	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
depends	O
on	O
its	O
mechanical	O
characteristic	O
(	O
large	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
less	O
prone	O
to	O
self	O
heating	O
)	O
.	O
</s>
<s>
To	O
prevent	O
failures	O
,	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
used	O
to	O
detect	O
and	O
locate	O
damages	O
and	O
creep	O
.	O
</s>
<s>
Resistive	O
foil	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
seldom	O
used	O
for	O
these	O
applications	O
,	O
however	O
,	O
due	O
to	O
their	O
low	O
strain	O
limit	O
.	O
</s>
<s>
Instead	O
,	O
soft	O
and	O
deformable	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
often	O
attached	O
to	O
a	O
host	O
garment	O
,	O
to	O
make	O
it	O
simple	O
to	O
apply	O
the	O
sensor	O
to	O
the	O
correct	O
part	O
of	O
the	O
body	O
,	O
though	O
sometimes	O
they	O
are	O
attached	O
directly	O
to	O
the	O
skin	O
.	O
</s>
<s>
Typically	O
in	O
these	O
applications	O
,	O
such	O
soft	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
known	O
as	O
stretch	O
sensors	O
.	O
</s>
<s>
Strain	B-Algorithm
gauges	I-Algorithm
can	O
be	O
used	O
to	O
monitor	O
the	O
strain	O
as	O
an	O
indicator	O
of	O
fatigue	O
in	O
materials	O
to	O
enable	O
software	O
systems	O
to	O
predict	O
when	O
certain	O
components	O
need	O
to	O
be	O
replaced	O
or	O
serviced	O
.	O
</s>
<s>
Resistive	O
foil	O
gauges	O
can	O
be	O
used	O
to	O
instrument	O
stiff	O
materials	O
like	O
metals	O
,	O
ceramics	O
,	O
composites	O
and	O
similar	O
,	O
whereas	O
highly	O
elastic	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
used	O
to	O
monitor	O
softer	O
materials	O
such	O
as	O
rubber	O
,	O
plastics	O
,	O
textiles	O
and	O
the	O
like	O
.	O
</s>
<s>
In	O
aviation	O
,	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
the	O
standard	O
approach	O
to	O
measuring	O
the	O
structural	O
load	O
and	O
calculating	O
wing	O
deflection	O
.	O
</s>
<s>
Strain	B-Algorithm
gauges	I-Algorithm
are	O
fixed	O
in	O
several	O
locations	O
on	O
the	O
aircraft	O
.	O
</s>
<s>
This	O
reduces	O
instrumentation	O
weight	O
on	O
the	O
aircraft	O
and	O
thus	O
is	O
replacing	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
.	O
</s>
<s>
So	O
for	O
example	O
in	O
the	O
detection	O
of	O
intruders	O
on	O
certain	O
structures	O
,	O
strain	B-Algorithm
gauges	I-Algorithm
can	O
be	O
used	O
to	O
detect	O
the	O
presence	O
of	O
such	O
an	O
intruder	O
.	O
</s>
<s>
As	O
the	O
temperature	O
rises	O
the	O
load	B-Algorithm
cell	I-Algorithm
element	O
becomes	O
more	O
elastic	O
and	O
therefore	O
under	O
a	O
constant	O
load	O
will	O
deform	O
more	O
and	O
lead	O
to	O
an	O
increase	O
in	O
output	O
;	O
but	O
the	O
load	O
is	O
still	O
the	O
same	O
.	O
</s>
<s>
EMI	O
induced	O
errors	O
-	O
As	O
strain	B-Algorithm
gauges	I-Algorithm
output	O
voltage	O
is	O
in	O
the	O
mV	O
range	O
,	O
even	O
μV	O
if	O
the	O
Wheatstone	O
bridge	O
voltage	O
drive	O
is	O
kept	O
low	O
to	O
avoid	O
self	O
heating	O
of	O
the	O
element	O
,	O
special	O
care	O
must	O
be	O
taken	O
in	O
output	O
signal	O
amplification	O
to	O
avoid	O
amplifying	O
also	O
the	O
superimposed	O
noise	O
.	O
</s>
<s>
Overloading	O
–	O
If	O
a	O
strain	B-Algorithm
gauge	I-Algorithm
is	O
loaded	O
beyond	O
its	O
design	O
limit	O
(	O
measured	O
in	O
microstrain	O
)	O
its	O
performance	O
degrades	O
and	O
can	O
not	O
be	O
recovered	O
.	O
</s>
<s>
Normally	O
good	O
engineering	O
practice	O
suggests	O
not	O
to	O
stress	O
strain	B-Algorithm
gauges	I-Algorithm
beyond	O
±3000	O
microstrain	O
.	O
</s>
<s>
Humidity	O
–	O
If	O
the	O
wires	O
connecting	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
to	O
the	O
signal	O
conditioner	O
are	O
not	O
protected	O
against	O
humidity	O
,	O
such	O
as	O
bare	O
wire	O
,	O
corrosion	O
can	O
occur	O
,	O
leading	O
to	O
parasitic	O
resistance	O
.	O
</s>
<s>
This	O
can	O
allow	O
currents	O
to	O
flow	O
between	O
the	O
wires	O
and	O
the	O
substrate	O
to	O
which	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
is	O
glued	O
,	O
or	O
between	O
the	O
two	O
wires	O
directly	O
,	O
introducing	O
an	O
error	O
which	O
competes	O
with	O
the	O
current	O
flowing	O
through	O
the	O
strain	B-Algorithm
gauge	I-Algorithm
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
high-current	O
,	O
low-resistance	O
strain	B-Algorithm
gauges	I-Algorithm
(	O
120	O
ohm	O
)	O
are	O
less	O
prone	O
to	O
this	O
type	O
of	O
error	O
.	O
</s>
<s>
To	O
avoid	O
this	O
error	O
it	O
is	O
sufficient	O
to	O
protect	O
the	O
strain	B-Algorithm
gauges	I-Algorithm
wires	O
with	O
insulating	O
enamel	O
(	O
e.g.	O
,	O
epoxy	O
or	O
polyurethane	O
type	O
)	O
.	O
</s>
<s>
Strain	B-Algorithm
gauges	I-Algorithm
with	O
unprotected	O
wires	O
may	O
be	O
used	O
only	O
in	O
a	O
dry	O
laboratory	O
environment	O
but	O
not	O
in	O
an	O
industrial	O
one	O
.	O
</s>
<s>
In	O
some	O
applications	O
,	O
strain	B-Algorithm
gauges	I-Algorithm
add	O
mass	O
and	O
damping	O
to	O
the	O
vibration	O
profiles	O
of	O
the	O
hardware	O
they	O
are	O
intended	O
to	O
measure	O
.	O
</s>
<s>
In	O
the	O
turbomachinery	O
industry	O
,	O
one	O
used	O
alternative	O
to	O
strain	B-Algorithm
gauge	I-Algorithm
technology	O
in	O
the	O
measurement	O
of	O
vibrations	O
on	O
rotating	O
hardware	O
is	O
the	O
non-intrusive	O
stress	O
measurement	O
system	O
,	O
which	O
allows	O
measurement	O
of	O
blade	O
vibrations	O
without	O
any	O
blade	O
or	O
disc-mounted	O
hardware	O
...	O
</s>
<s>
The	O
following	O
different	O
kind	O
of	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
available	O
in	O
the	O
market	O
:	O
</s>
<s>
Strain	B-Algorithm
Gauge	I-Algorithm
measurement	O
devices	O
are	O
prone	O
to	O
drift	O
problems	O
.	O
</s>
<s>
For	O
measurements	O
of	O
small	O
strain	O
,	O
semiconductor	O
strain	B-Algorithm
gauges	I-Algorithm
,	O
so	O
called	O
piezoresistors	O
,	O
are	O
often	O
preferred	O
over	O
foil	O
gauges	O
.	O
</s>
<s>
Nanoparticle-based	O
strain	B-Algorithm
gauges	I-Algorithm
emerge	O
as	O
a	O
new	O
promising	O
technology	O
.	O
</s>
<s>
In	O
biological	O
measurements	O
,	O
especially	O
blood	O
flow	O
and	O
tissue	O
swelling	O
,	O
a	O
variant	O
called	O
mercury-in-rubber	O
strain	B-Algorithm
gauge	I-Algorithm
is	O
used	O
.	O
</s>
<s>
This	O
kind	O
of	O
strain	B-Algorithm
gauge	I-Algorithm
consists	O
of	O
a	O
small	O
amount	O
of	O
liquid	O
mercury	O
enclosed	O
in	O
a	O
small	O
rubber	O
tube	O
,	O
which	O
is	O
applied	O
around	O
e.g.	O
,	O
a	O
toe	O
or	O
leg	O
.	O
</s>
<s>
Fiber	B-Algorithm
optic	I-Algorithm
sensing	I-Algorithm
can	O
be	O
employed	O
to	O
measure	O
strain	O
along	O
an	O
optical	B-Architecture
fiber	I-Architecture
.	O
</s>
<s>
Microscale	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
widely	O
used	O
in	O
microelectromechanical	B-Architecture
systems	I-Architecture
(	O
MEMS	B-Architecture
)	O
to	O
measure	O
strains	O
such	O
as	O
those	O
induced	O
by	O
force	O
,	O
acceleration	O
,	O
pressure	O
or	O
sound	O
.	O
</s>
<s>
As	O
example	O
,	O
airbags	O
in	O
cars	O
are	O
often	O
triggered	O
with	O
MEMS	B-Architecture
accelerometers	O
.	O
</s>
<s>
As	O
alternative	O
to	O
piezo-resistant	O
strain	B-Algorithm
gauges	I-Algorithm
,	O
integrated	O
optical	O
ring	O
resonators	O
may	O
be	O
used	O
to	O
measure	O
strain	O
in	O
microoptoelectromechanical	O
systems	O
(	O
MOEMS	O
)	O
.	O
</s>
<s>
Capacitive	O
strain	B-Algorithm
gauges	I-Algorithm
use	O
a	O
variable	O
capacitor	O
to	O
indicate	O
the	O
level	O
of	O
mechanical	O
deformation	O
.	O
</s>
<s>
Vibrating	O
wire	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
used	O
in	O
geotechnical	O
and	O
civil	O
engineering	O
applications	O
.	O
</s>
<s>
Quartz	O
crystal	O
strain	B-Algorithm
gauges	I-Algorithm
are	O
also	O
used	O
in	O
geotechnical	O
applications	O
.	O
</s>
<s>
A	O
pressure	O
sensor	O
,	O
a	O
resonant	O
quartz	O
crystal	O
strain	B-Algorithm
gauge	I-Algorithm
with	O
a	O
bourdon	O
tube	O
force	O
collector	O
is	O
the	O
critical	O
sensor	O
of	O
DART	O
.	O
</s>
<s>
DART	O
detects	O
tsunami	B-Application
waves	O
from	O
the	O
bottom	O
of	O
the	O
open	O
ocean	O
.	O
</s>
<s>
Multi-axis	O
force	O
sensors	O
could	O
have	O
plenty	O
of	O
advantages	O
over	O
strain	B-Algorithm
gauges	I-Algorithm
regarding	O
their	O
safety	O
,	O
dexterity	O
,	O
and	O
collaborative	O
perspectives	O
.	O
</s>
<s>
Moreover	O
,	O
the	O
hardware	O
needed	O
is	O
cheaper	O
than	O
classical	O
strain	B-Algorithm
gauges	I-Algorithm
.	O
</s>
<s>
The	O
full	O
strain	O
map	O
of	O
the	O
tested	O
sample	O
can	O
be	O
calculated	O
,	O
providing	O
similar	O
display	O
as	O
a	O
finite-element	B-Application
analysis	I-Application
.	O
</s>
<s>
This	O
technique	O
is	O
used	O
in	O
many	O
industries	O
to	O
replace	O
traditional	O
strain	B-Algorithm
gauges	I-Algorithm
or	O
other	O
sensors	O
like	O
extensometers	O
,	O
string	O
pots	O
,	O
LVDT	B-Algorithm
,	O
accelerometers	O
...	O
</s>
<s>
They	O
produce	O
strain	B-Algorithm
gauges	I-Algorithm
for	O
diverse	O
mounting	O
surfaces	O
,	O
sizes	O
,	O
and	O
shapes	O
.	O
</s>
<s>
One	O
needs	O
the	O
knowledge	O
of	O
the	O
exact	O
setup	O
process	O
of	O
strain	B-Algorithm
gauges	I-Algorithm
to	O
ensure	O
the	O
collection	O
of	O
usable	O
data	O
.	O
</s>
<s>
The	O
large	O
providers	O
of	O
strain	B-Algorithm
gauges	I-Algorithm
provide	O
consultation	O
on	O
the	O
correct	O
choice	O
for	O
each	O
application	O
.	O
</s>
<s>
One	O
of	O
the	O
leading	O
companies	O
is	O
Zemic	O
Europe	O
,	O
offering	O
thousands	O
of	O
different	O
types	O
of	O
strain	B-Algorithm
gauges	I-Algorithm
.	O
</s>
<s>
They	O
offer	O
a	O
wide	O
variety	O
of	O
strain	B-Algorithm
gauges	I-Algorithm
and	O
associated	O
products	O
.	O
</s>
<s>
Stefan	O
Keil	O
published	O
the	O
first	O
edition	O
of	O
a	O
detailed	O
book	O
about	O
strain	B-Algorithm
gauges	I-Algorithm
and	O
how	O
to	O
use	O
them	O
called	O
“	O
Dehnungsmessstreifen	O
”	O
.	O
</s>
<s>
Although	O
this	O
first	O
edition	O
was	O
only	O
published	O
in	O
German	O
,	O
it	O
became	O
popular	O
outside	O
of	O
Germany	O
because	O
of	O
the	O
wide	O
range	O
of	O
uses	O
of	O
strain	B-Algorithm
gauges	I-Algorithm
in	O
different	O
fields	O
.	O
</s>
<s>
After	O
more	O
than	O
20	O
years	O
(	O
in	O
2017	O
)	O
,	O
he	O
published	O
a	O
second	O
edition	O
that	O
was	O
translated	O
into	O
English	O
,	O
hence	O
available	O
to	O
more	O
engineers	O
that	O
use	O
strain	B-Algorithm
gauges	I-Algorithm
.	O
</s>
<s>
This	O
newest	O
book	O
is	O
titled	O
“	O
Technology	O
and	O
Practical	O
Use	O
of	O
Strain	B-Algorithm
Gages	I-Algorithm
”	O
.	O
</s>
<s>
The	O
term	O
“	O
strain	B-Algorithm
gauge	I-Algorithm
”	O
can	O
be	O
encountered	O
in	O
sociology	O
.	O
</s>
<s>
The	O
social	O
strain	B-Algorithm
gauge	I-Algorithm
theory	O
is	O
an	O
approach	O
to	O
understanding	O
accusations	O
of	O
witchcraft	O
and	O
sorcery	O
.	O
</s>
