MTS Series 311 Load Frame - Manual (Page 17)

Functional Description
Series 311 Load Frame Introduction 17
Functional Description
The load frame is a stand alone testing structure. The following components are
used with the load frame:
• Crosshead lifts and locks
• Actuator
• Servovalves
• Hydraulic manifold
• Transducers
– Force
– Displacement
Load frame
The load frame is the basic structure which provides the reaction mass for the
force train. The base of the load frame is one end of the reaction mass and the
crosshead is the other end of the reaction mass. Installing a specimen and other
fixtures or components between the load frame base and the crosshead create a
force train.
The crosshead is mounted above the base by four columns. A control panel lets
you operate the crosshead lifts, locks, and grips to assist in specimen installation
procedures.
Crosshead lifts
and locks
The crosshead can be positioned anywhere along the load frame columns. It is
moved along the column with hydraulic lifts. When the crosshead is in an
appropriate test position, it is hydraulically clamped to that position. This lets
you change the load frame to accommodate specimens of different lengths.
Actuators
The actuator can be located in the middle of the load frame base or crosshead. It
is a hydraulically powered piston that applies displacement of (or force into) a
specimen. It can apply equal power in tension and compression. One end of the
test specimen is installed into a fixture which is mounted to the end of the
actuator rod.
Servovalves
A servovalves regulates the direction and flow of the hydraulic fluid to and from
a hydraulic actuator. The servovalve responds to the polarity and magnitude of
the command signal generated by the controller.
Hydraulic manifold
A hydraulic manifold (also called an actuator manifold or hydraulic service
manifold) controls the hydraulic pressure to the load frame. The manifold
includes solenoid valves that control the hydraulic pressure (off, low, or high).
An actuator manifold is mounted directly to the actuator on the load frame. A
hydraulic service manifold (HSM) is located near the load frame and connects to
the actuator with hydraulic hoses.