Where – MTS Series 609 Alignment Fixture User Manual
Page 33
Calculating Bending Strain—Round Thick Diameter
Series 609 Alignment Fixture Product Information
Specimen Preparation
33
Use this formula to find the average axial strain (A):
Where:
ε
1
through
ε
12
are the strain readings from gages 1 through 12
Au is the average strain of the upper gages
Am is the average strain of the middle gages
Al is the average strain of the lower gages
4. Calculate the percent bending strain for each level.
Use this formula to find the percent bending strain (PBS):
Where:
Bu is the bending strain of the upper gages
Bm is the bending strain of the middle gages
Bl is the bending strain of the lower gages
Au is the average strain of the upper gages
Am is the average strain of the middle gages
Al is the average strain of the lower gages
5. Calculate the direction of the maximum strain for each level.
Use this formula to find the direction (
φ) of the maximum (most tensile)
bending strain:
Where:
(
φ) is measured from the highest reading (most tensile) strain gage toward
the second highest reading strain gage
Bu
x
is the highest strain of the x axis of the upper gages
Bm
x
is the highest strain of the x axis of the middle gages
Bl
x
is the highest strain of the x axis of the lower gages
Bu
y
is the highest strain of the y axis of the upper gages
Bm
y
is the highest strain of the y axis of the middle gages
Bl
y
is the highest strain of the y axis of the lower gages
The bending strain directions for all levels should generally agree if you
have satisfactorily removed the “S” bend.
Au
ε
1
ε
2
ε
3
ε
4
+
+
+
4
---------------------------------------
=
Am
ε
5
ε
6
ε
7
ε
8
+
+
+
4
---------------------------------------
=
Al
ε
9
ε
10
ε
11
ε
12
+
+
+
4
----------------------------------------------
=
Upper Gages
Middle Gages
Lower Gages
PBSu
Bu
Au
------- 100
×
=
PBSm
Bm
Am
-------- 100
×
=
PBSl
Bl
Al
----- 100
×
=
Upper Gages
Middle Gages
Lower Gages
φ
arc
Bu
x
Bu
y
---------
tan
=
φ
arc
Bm
x
Bm
y
----------
tan
=
φ
arc
Bl
x
Bl
y
-------
tan
=
Upper Gages
Middle Gages
Lower Gages