Construction of a Machine for Biaxial Mechanical Tests: Tension and Torsion, Destined to Membrane Materials
A self-designed and constructed machine destined to biaxial tension-torsion tests (MBTT), has been developed. This machine is destined to carry out tests under this modality of loading on membranes with the thickness from 50 to 1500 m. Control of this machine is implemented by the software Arduino 1.8.1, which is an open, easy and reliable software. Detailed description of the machine's elements is included and the listing of the control Arduino program is developed. The technical capacities of this machine are: from 1 to 70 MPa of tension load and up to 180 degrees of torsion, from room temperature to 80° C, and environmental to saturated humidity. In order to validate this testing machine, tests are obtained on the Nafion 115 material used as proton exchange membrane in the fuel cells, which thickness is 127 m. These first experimental tests were obtained under the following conditions: room temperature (22-25° C), environmental humidity (50-55%), tension loading of: 40, 45, 50, 55 and 60 MPa, and a constant torsion angle of 50. Experimental results show the capacity and reliability of this machine, which are discussed in the last section of this paper, together with general comment of these first results.
Keywords- Biaxial Mode, Tension, Torsion, Membranes.