MTS Series 609 Alignment Fixture - Manual (Page 39)

Calculating Bending Strain—Flat Thick Specimens
Series 609 Alignment Fixture Product Information Specimen Preparation 39
3. 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
Calculate the strain for both axis (PBS
x
and PBS
y
).
4. Determine which axis is bending.
• Bending strain along one axis (usually the y axis) can be corrected by
clamping and unclamping the specimen.
• Bending strain along the other axis (usual the x axis) can be corrected
by using the alignment fixture.
PBS
Bu
Au
------- 100 × = PBS
Bm
Am
-------- 100 × = PBS
Bl
Al
----- 100 × =
Upper Gages Middle Gages Lower Gages