Geokon 1300, Инструкция по эксплуатации

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10
The Model 4430 deformation meter length temperature correction (L
C
) is calculated using
Equation 5.
L
C
= 17.3

10 -6

L

(T
1
- T
0
)
Equation 5 – Deformation Meter Length Correction
Where L is the length of deformation meter in millimeters or inches, (see Table 2),
The rod length correction (L
R
) is calculated from the equation 6
L
R
= K
R

S

(T
1
- T
0
)
Equation 6 – Rod Length Temperature Correction
Where S is the distance between anchor points minus the length of the transducer in mm or
inches and K
R
is the coeficient of expansion of the rod material from Table 3
Rod Material K
R
Thermal Coefficient
Per º C
Stainless Steel 17.3 x 10
-6
Graphite 0.2 x 10
-6
Fiberglass 6.0 x 10
-6
Table 3. Thermal coefficients of expansion for various rod materials
Example for the same 25mm range transducer as before where the anchor spacing is 144 inches
and the rods are fiberglass
R
1
= 4523
T
o
= 15 degrees C
T
1
= 30 degrees C
S= 144-10.5 = 133.5 inches
Then K = [4523 x 0.0.572] x 0.0001755 = 0.00039
And the total temperature correction
(T
1
-T
0
) [ K + L
C
+L
R
] =
(30 – 15) x [ 0.00039 + 10.5 x 17.3 x10
-6
+ 133.5 x 6.0 x10
-6
] = +0.0206 inches
And the Total deformation, temperature corrected, is -0.1016 + 0.0206 = -0.081 inches and the
measured strain is -0.081/144 x 10^6 = - 562 microstrain in compression