MTS Systems 318 Series Product Information page 22

D
EFLECTIONS
A - B base
B - C columns
C - D crosshead
22 Introduction
For the most accurate high frequency test results, use a load unit with a fatigue
rating that is larger than its actuator's force rating.
C
B
For example, a Model 318.25 Load Unit with a 55 kip fatigue rating and a 22 kip
actuator will have smaller deflections than a Model 318.10 Load Unit with a 22
kip fatigue rating and a 22 kip actuator.
Spring rates are determined at each load unit's full fatigue rating with its
crosshead raised 1270 mm (50 in.) above the baseplate.
The Stiffness Graph shows how stiffness is affected when the height of the
crosshead is changed.
M 318.10
ODEL
100 N/22
K KIP
0.15 mm 0.006 in
0.10 mm 0.004 in
0.13 mm 0.005 in
D
A
M 318.25
ODEL
250 N/55
K KIP
0.18 mm 0.007 in
0.15 mm 0.006 in
0.25 mm 0.010 in
M 318.50
ODEL
500 N/110
K KIP
0.20 mm 0.008 in
0.18 mm 0.007 in
0.28 mm 0.011 in
318 Load Unit