MTS Series 609 Alignment Fixture - Manual (Page 17)

About Angular Misalignment
Series 609 Alignment Fixture Product Information Introduction 17
Improving Concentric Alignment
About Angular Misalignment
Angular misalignment angles the upper grip’s loading axis away from the lower
grip’s loading axis. This misalignment puts a “C”-shaped bend in the specimen.
A specimen with a “C” bend has a side with higher than average strains and a
side opposite with lower than average strains. The bending strain is uniform over
the entire gage section.
Again, actual strain readings vary with the amount of tensile load applied to the
specimen.
With zero or low tensile force applied to the specimen, you can have tensile
readings on one side of the specimen and compressive strain readings on the
other side of the specimen.
Under higher tensile force, you can have higher tensile readings on one side of
the specimen and lower tensile readings on the other side of the specimen.
Concentricity Collar
Concentricity Adjustment Screws
Before and After
Concentric
Adjustment
Misalignment