MTS Series 215 Rotary Actuator - Manual (Page 41)

Definition of Useful Mathematical Terms
Series 215 Rotary Actuator Product Manual Operation 41
E S Modulus of elasticity of the base plate or
T-slot table, shear (N/m
2
) (lb/in.
2
)
L 2 Length of test specimen (mm) (in.). Do not
include specimen adapter plates unless their
compliance is equal to or greater than that of
the specimen.
E T Modulus of elasticity of the specimen,
tension (N/m
2
) (lb/in.
2
).
L F Distance between flexing points of
diaphragm flexures.
I
Moment of inertia for a round solid (mm
4
)
(in. 4 )
πr4/4
M Bending moment on test specimen with no
flexures (N·m) (lbf·in.).
PL 22
k 1 Torsional stiffness of a thin flat plate (N-
m./rad) (lbf-in./rad)
Es (β)bd 3 /L
1
M 1 Bending moment on actuator and reaction
bracket with standard flexures installed (N-
m) (lbf-in.).
k F1 θ
Μ2 Bending moment on test specimen with
standard flexures or diaphragm flexures
installed (N-m) (lbf-in.).
(Standard Flexures)
(Diaphragm Flexures)
T Applied torque (N-m) (lbf-in.)
M
F 1 Maximum lateral bending capacity of
standard flexures (N-m) (lbf-in.) u Distance from front bearing to specimen
(mm) (in.). Include specimen adapter plates
if they are less compliant than the specimen.
M
F 2 Maximum horizontal bending capacity of
diaphragm flexures (N-m) (lbf-in.) W Load on front actuator bearing (kN) (lbf)
P Side load imposed on test specimen and
actuator.
=k2k1aT1 + k2k1a2
∆ Centerline offset between actuator and
reaction bracket mountings due to twisting of
base plate or T-slot table (mm) (in.).
∆ =
r Radius of test specimen (mm) (in.) q Angle of flex imposed on flexures (rad).
(Standard Flexures)
(Diaphragm Flexures)
Mathematical Terms (part 2 of 3)
T ERM D EFINITION T ERM D EFINITION