Servohydraulic test frames
Foreground center, test frame of 100,000 pound capacity. Left, blue base and top, test frame of 12,000 pound capacity optimized for fatigue tests and rapid transients. This frame has an updated digital control system with a new monitor and controller, and newer Windows PC based software called "flex test".
Right, two test frames of 20,000 pound capacity.
Remark - as of 2024 this facility has been converted from teaching to research. Instruments may be available for projects.
Right, control electronics. Center, test frame of 20,000 pound capacity. Any digital scope will provide user friendly digital data access. The digital scopes we have can be used as web servers for data access. Digital scopes also allow easy export of waveform data via USB drives.
Detail of control electronics: type 442 controller; type 410 digital function generator; type 413 master control panel. Test frame has 20,000 pound capacity. Analog control is user friendly and allows rapid learning. Advanced and helpful capabilities include the following.
Display of error signal between program and actual variable is always on. It permits usage without unexpected motion of the instrument. It is easy to see when instrument is properly zeroed prior to a test.
Functions used during initial set up are clearly delineated from functions used during testing.
A digital scope may be connected via analog ports. Digital scopes offer capabilities including signal averaging for noise reduction and fast Fourier transform. Waveforms visible on the scope are readily exported digitally. This capability is superior to some PC based systems that show a waveform on the screen but require the user to redo the experiment to obtain digital data.
Startup is immediate.
Haver-sine and haver-square waveforms are immediately available for compression and tension testing, superior to some digital PC based systems.
It is easy to apply a single pulse, rectangular in time, rather than a repeating waveform. A single pulse essential for stress relaxation testing in displacement control or creep testing in load control, followed by recovery. This capability is superior to some digital PC based systems.
We have all done software coding, some of us in many languages. It is not at all difficult to obtain the capabilities of the analog frame in a digital control system. They did not do so. It is pertinent to consider why.