MTS Series 609 Alignment Fixture - Manual (Page 43)

Calculating Bending Strain—Notched Round Thick
Series 609 Alignment Fixture Product Information Specimen Preparation 43
Calculating Bending Strain—Notched Round Thick Diameter Specimens
This section shows how to calculate the bending strain for round specimens with
four gages at each level.
Gage Placement
1. Calculate the bending strains for each level.
Use these formulas to find the x axis (B
x
) and y axis (B
y
) bending strains of
each level:
Where: ε
1
through ε
8
are the strain readings from gages 1 through 8
Bu
x
is the bending strain of the x axis of the upper gages
Bl
x
is the bending strain of the x axis of the lower gages
Bu
y
is the bending strain of the y axis of the upper gages
Bl
y
is the bending strain of the y axis of the lower gages
Do not ignore the signs on negative numbers.
2. Calculate the maximum bending strain for each level.
Use this formula to find the maximum bending strain (B):
Where: Bu is the bending strain of the upper gages
Bl is the bending strain of the lower gages
3. Calculate the average axial strain for each level.
Use this formula to find the average axial strain (A):
Bu
x
ε
1
ε
3
–
2
---------------- =
Bu
y
ε
2
ε
4
–
2
---------------- =
Bl
x
ε
5
ε
7
–
2
---------------- =
Bl
y
ε
6
ε
8
–
2
---------------- =
Upper Gages Lower Gages
Bu Bu
x
( )
2
Bu
y
( )
2
+ = Bl Bl
x
( )
2
Bl
y
( )
2
+ =
Upper Gages Lower Gages