<s>
An	O
Electrochemical	B-Algorithm
Fatigue	I-Algorithm
Crack	I-Algorithm
Sensor	I-Algorithm
(	O
EFCS	O
)	O
is	O
a	O
type	O
of	O
low	O
cost	O
electrochemical	O
nondestructive	O
dynamic	O
testing	O
method	O
used	O
primarily	O
in	O
the	O
aerospace	O
and	O
transportation	O
infrastructure	O
industries	O
.	O
</s>
<s>
The	O
output	O
current	O
resembles	O
a	O
heart	O
’s	O
EKG	B-Application
pattern	O
and	O
can	O
be	O
interpreted	O
to	O
indicate	O
the	O
degree	O
of	O
fatigue	O
as	O
well	O
as	O
the	O
presence	O
of	O
cracks	O
in	O
their	O
earliest	O
stages	O
of	O
development	O
.	O
</s>
<s>
The	O
Electrochemical	O
Fatigue	O
Sensor	O
(	O
EFS	O
)	O
is	O
a	O
nondestructive	O
crack	O
dynamic	O
inspection	O
technology	O
,	O
similar	O
in	O
concept	O
to	O
a	O
medical	O
EKG	B-Application
,	O
which	O
is	O
used	O
to	O
determine	O
if	O
actively	O
growing	O
fatigue	O
cracks	O
are	O
present	O
.	O
</s>
<s>
Grade	O
5	O
,	O
also	O
known	O
as	O
Ti6Al4V	O
,	O
Ti-6Al-4V	O
or	O
Ti	O
6-4	O
,	O
is	O
the	O
most	O
commonly	O
used	O
titanium	O
alloy	B-Application
in	O
the	O
aerospace	O
industry	O
,	O
e.g.	O
</s>
<s>
By	O
comparison	O
,	O
annealed	O
type	O
316	O
stainless	O
steel	O
has	O
a	O
density	O
of	O
8000kg/m3	O
,	O
modulus	O
of	O
193	O
GPa	O
,	O
and	O
tensile	O
strength	O
of	O
only	O
570	O
MPa	O
and	O
tempered	O
6061	O
aluminum	O
alloy	B-Application
has	O
a	O
density	O
of	O
2700kg/m3	O
,	O
modulus	O
of	O
69	O
GPa	O
,	O
and	O
tensile	O
strength	O
of	O
310	O
MPa	O
)	O
.	O
</s>
<s>
EFS	O
detects	O
growing	O
cracks	O
in	O
steel	O
,	O
aluminum	O
,	O
titanium	O
alloys	B-Application
,	O
and	O
other	O
metals	O
.	O
</s>
<s>
The	O
inspectors	O
wire	O
up	O
the	O
areas	O
with	O
sensors	O
,	O
which	O
are	O
similar	O
to	O
the	O
peel-and-stick	O
versions	O
used	O
for	O
an	O
EKG	B-Application
reading	O
.	O
</s>
