CORROSION ESTIMATION DEVICE AND METHOD
The corrosion estimation device includes a sensor, a first processing circuit, a second processing circuit, and a third processing circuit. The sensor measures a water content of soil of a target land. The first processing circuit estimates a damping function representing a temporal change in a ratio of an area wetted with water on a surface of a metal structure buried in the target land on the basis of a water content measurement value measured by the sensor. The second processing circuit estimates, from the estimated damping function, a rate increase function that increases the corrosion rate of the metal structure, the rate increase function being derived from a thickness of a water film formed on the surface of the metal structure. The third processing circuit estimates a temporal change function of the corrosion rate given by a product of the damping function and the rate increase function.
1 - 4 . (canceled)
5 . A corrosion estimation method comprising:
a measurement step of measuring a water content of soil of a target land;
a first processing step of estimating a damping function representing a temporal change in a ratio of an area wetted with water on a surface of a metal structure buried in the target land based the water content measured in the measurement step;
a second processing step of estimating a rate increase function that increases an estimated corrosion rate of the metal structure, the rate increase function estimated based on the damping function and a thickness of a water film formed on the surface of the metal structure; and
a third processing step of estimating a temporal change function of the estimated corrosion rate based on a product of the damping function and the rate increase function.
6 . The corrosion estimation method according to claim 5 , further comprising:
a fourth processing step of obtaining the estimated corrosion rate of the metal structure from the measured water content of the soil of the target land based on the temporal change function.
7 . The corrosion estimation method according to claim 5 , wherein the damping function is presented by:
Y
1
=
{
1
1
+
a
·
e
b
(
t
-
t
1
)
}
,
wherein Y1 is the damping function, t is time, and a, b, and t1 are constants.
8 . The corrosion estimation method according to claim 7 , wherein the rate increase function is represented by:
Y
2
=
{
α
·
K
·
e
β
(
t
-
t
0
)
(
K
-
α
)
+
e
β
(
t
-
t
0
)
+
γ
}
,
wherein Y2 is the rate increase function, and K, α, β, γ, and t 0 are constants.
9 . The corrosion estimation method according to claim 8 , wherein the temporal change function is represented by:
Y
=
{
α
·
K
·
e
β
(
t
-
t
0
)
(
K
-
α
)
+
e
β
(
t
-
t
0
)
+
γ
}
×
{
1
1
+
a
·
e
b
(
t
-
t
1
)
}
,
wherein Y is the temporal change function.
10 . A corrosion estimation device comprising:
a sensor configured to measure a water content of soil of a target land;
a storage device comprising instructions; and
one or more processors in communication with the storage device, wherein the one or more processors execute the instructions to:
estimate a damping function representing a temporal change in a ratio of an area wetted with water on a surface of a metal structure buried in the target land based on the water content measured by the sensor;
estimate a rate increase function that increases an estimated corrosion rate of the metal structure, the rate increase function being derived based on the damping function and a thickness of a water film on the surface of the metal structure; and
estimate a temporal change function of the estimated corrosion rate based on a product of the damping function and the rate increase function.
11 . The corrosion estimation device according to claim 10 , wherein the one or more processors execute the instructions to further:
obtain the estimated corrosion rate of the metal structure from the measured water content of the soil of the target land based on the temporal change function.
12 . The corrosion estimation device according to claim 10 , wherein the damping function is presented by:
Y
1
=
{
1
1
+
a
·
e
b
(
t
-
t
1
)
}
,
wherein Y1 is the damping function, t is time, and a, b, and t1 are constants.
13 . The corrosion estimation device according to claim 12 , wherein the rate increase function is represented by:
Y
2
=
{
α
·
K
·
e
β
(
t
-
t
0
)
(
K
-
α
)
+
e
β
(
t
-
t
0
)
+
γ
}
,
wherein Y2 is the rate increase function, and K, α, β, γ, and t 0 are constants.
14 . The corrosion estimation device according to claim 13 , wherein the temporal change function is represented by:
Y
=
{
α
·
K
·
e
β
(
t
-
t
0
)
(
K
-
α
)
+
e
β
(
t
-
t
0
)
+
γ
}
×
{
1
1
+
a
·
e
b
(
t
-
t
1
)
}
,
wherein Y is the temporal change function.