MTS Series 311 Load Frame - Manual (Page 44)

Series 311 Load Frame 44
Installing a Specimen
Operation
Installing a Specimen
The procedure to install a specimen varies due to the variety of test fixtures,
grips, and the type of specimen being installed. This section should be considered
a guideline. You need to modify this procedure to suit your equipment.
Prerequisite
You must have the necessary grips and/or fixturing installed. You must also have
the controller set up to control the actuator movement, and you must have a test
program defined.
Procedure
1. Set things up for specimen installation.
A. Ensure that the crosshead is locked.
B. Turn on system electrical power.
C. Turn on high hydraulic pressure.
D. Adjust the actuator to its start position (usually mid-displacement). The
starting position of the actuator depends on the type of fixtures, grips,
and the test being set up.
The crosshead can slowly drift down the columns if the locks are turned off
and when hydraulic pressure is turned off.
The crosshead can damage any test fixtures, grips, and specimen in its
path.
Unlock the crosshead only to reposition it. Always lock the crosshead after you
have repositioned it, and never leave the crosshead unlocked.
2. Set the crosshead position.
The crosshead position depends on the length of the specimen being tested,
the starting position of the actuator, and the size of the fixtures or grips
being used.
A. This step pressurizes the lift actuators. The crosshead might have
shifted position while hydraulic pressure was turned off.
Briefly turn the Crosshead Lift/Lock Controls to the lift
crosshead position to apply a slight upward pressure to the
crosshead.
Then return the lift control to the stop position.
B. Use the Crosshead Lift/Lock Controls to unclamp the
crosshead. Wait 30 seconds for the pressure in the crosshead
locks to drop to zero.
CAUTION