24
en
where:
= Average length under stress
= Clamp length
= Additional diameter added for head, nut(s), and or blind hole
Note: A convenient way to perform the above Load Factor calculations is to use the bolt calculator included
in the Bolt Link PC software.
It is important to note that performing the calculations above is only a good approximation at best. In all
cases, if possible, a field calibration should be performed if you intend to perform measurements in terms
of load.
11.2 CALIBRATING A LOAD FACTOR (FIELD CALIBRATION)
Clearly, the most effective way of
calibrating the load factor is by
performing a field calibration.
Material constants are often
unknown or cannot be calibrated in
a laboratory environment. In cases
such as these, a field calibration is
the most accurate means of
calibration. A field calibration is
accomplished using a tensile
tester, load cell, or other calibrated
load device to compare known
loads against ultrasonic
elongations. Your gauge is
equipped with a self-calibrating
feature that uses a linear
regression or vector equation to
L
E
C
L
D
X
+
=
L
E
C
L
D
X
Elongation (in time as measured by the gauge)
Applied
Load
(Mea
sur
ed by Tensile Machine)
