MTS Series 609 Alignment Fixture - Manual (Page 30)

Series 609 Alignment Fixture Product Information 30
About Gaged Specimens
Specimen Preparation
Because misalignment produces bending strain, many test procedures verify
alignment by specifying the maximum bending strain allowed in a specimen at a
given load. This is expressed as a percent of axial strain and is usually limited to
5–10% of axial strain. Specimens with strain gages are used to measure the
maximum bending strain.
A typical gaged specimen has three levels of strain gages in its gage section. The
gages allow you to determine bending strains at each level.
In addition, the strain readings give you a picture of the “S” and “C” bends
caused by concentric and angular misalignment. Used with the formulas in this
section, they show how to move the alignment fixture to improve alignment.
Note Before beginning the alignment procedure, review the formulas in this
section. You may want to write a computer program to work through the
formulas or you can purchase the Model 709 Easy Alignment software
from MTS Systems Corporation.