We are three undergraduate students at the School of Mechanics of Universidad Tecnológica Nacional located in Buenos Aires, Argentina.

In our opinion, computer data acquisition is a basic tool that we need to be used to use. That’s why we have decided to start by the digitalization of our old tensile test machine. To be able to do that, it is necessary at first to have the hardware & software.

The IT hardware we have:
• Tensile test 60 Ton AMSLER machine
• NI data adquisitor DAQ-9237 usb
• MTS extensometer
• 10 Ton Load cell

Software: NI LabVIEW

The main activity was to design software which could relate two signals (by the extensometer & load cell) and print those in a X-Y chart. To do this we had two alternatives:

One was to go to buy the original manufacturer equipment that costs thousands of dollars.

The other solution was to achieve computer data acquisition by using the existing 60 Ton AMSLER machine, together with the computer data acquisition hardware and software.

The second alternative is the one we have chosen because it represents zero cost spent specially on the machine & instruments, and at the same time give us the posibility to gain experience and knowledge

Summary:

The load cell and extensometer´s operating principles consist of a Wheatstone bridge which sends a variable signal related with the instrument´s linear deformation. Those signals are acquired by the data adquisitor and sent to our LabVIEW software where this information is printed in a X-Y chart. The X-Y chart shows the elongation vs applied load. This generates a stress-strain curve in real time.