MTS Series 215 Rotary Actuator - Manual (Page 53)

Test Setup Using Diaphragm Flexures
Series 215 Rotary Actuator Product Manual Operation 53
Calculate bending
moment (M2)
Calculate the bending moment (M 2 ) that is induced in the test specimen with
diaphragm flexures installed by using the following formula:
Calculate specimen
stress
Calculate the additional stress (SB) induced in the specimen due to base plate
twist by using the following formula:
The value 10.4 psi represents the amount of stress experienced by the specimen
under test and is an acceptable stress level. Typically, in a torsion test, stress
caused by reaction base or T-slot table twist should be zero or as close to zero as
possible. Specimen stress loading introduces unfavorable loads on the test
specimen which can invalidate the test results or cause premature failure of the
specimen.