MTS Tension Compression Grips - Manual (Page 21)

3-6 Installation
1. Select force control at the system controller.
WARNING
Sudden actuator movement may result if system hydraulic
pressure is applied while the dc error (command =
feedback) is other than zero.
This may cause injury to personnel and/or damage to
e q u i p m e n t .
Zero the dc error before applying system hydraulic pressure.
2. Adjust the system controller for zero dc error and apply system
hydraulic pressure according to applicable system procedures.
3. Select a dummy specimen that will withstand a tensile force 10
to 20% greater than the maximum force to be applied during
the test.
4. Install the dummy specimen in the grips according to the steps
provided in Subsection 2.1 of this manual for button-end
specimens or Subsection 2.2 for threaded specimens.
5. Apply a static tensile force 10 to 20% higher than the maximum
force to be applied during testing.
CAUTION
Improper preloading of the connector stud can subject the
connector stud to cyclic loads which can cause eventual
fatigue resulting in connector stud breakage.
Sufficiently tightened the spiral washers as described in step 6.
6. Using spanner wrenches, rotate the two halves of the spiral
washers in opposite directions to tighten them (refer to Figure
3-2). The opening between the washers must not exceed an arc
of 30
°
from the closed position. If more than a 30
°
arc is
created, remove the tensile load from the specimen. Remove
the specimen (according to the steps provided in Subsection
2.3 of this manual), tighten the grips on the mounting studs.
Repeat steps 2 through 8 of this procedure.
7. Reduce tensile force to zero and remove the specimen.
8. Remove system hydraulic pressure.