Dakota Ultrasonics MINI--MAX - Manual (Page 107)

MINI-MAX Ultrasonic Bolt Tension Monitor
101
3) Record the ultrasonic length “L
0
” of the sample bolt at the above
minimum temperature - 48
0
F.
4) Repeat step 1 - 3 at the target temperatures (T
1
through T
5
) – 48, 68,
88, and 108
0
F (other similar range with 5 temperatures), measuring the
ultrasonic lengths (L
1
through L
5
) respectively. This process must be
done for each of the sample bolts in the experiment.
5) Use the equation below to calculate a linear regression, using the
temperatures and lengths recorded for all the sample bolts to determine
the temperature factor.
( )( )
( )
6
2
2
10
∗
−
−
=
∑
∑
∑
∑ ∑
n
x
x
n
y x
xy
eFactor Temperatur
x = temperature, y = change in reference length, n = number of sample points per bolt