Diseño y construcción de un sistema para realizar ensayos a tracción de materiales poliméricos en la maquina universal de la Falcultad de Mecánica (ESPOCH)

Abstract

In the present work, a system of clamps for polymers was designed and built, it will be used in the universal machine located in the Faculty of Mechanics of the ESPOCH. The design was based on the type of flat specimens, with a maximum thickness of 8 mm and the geometry indicated by the ASTM D638 standard. The conceptual design was started to meet the system requirements. Then the best alternative was selected under the parameters found, the forces supported by the jaws were calculated, in order to obtain the dimensions, guaranteeing that it will not undergo deformation, while tensile tests are carried out under standardized parameters. AISI 01 steel was considered for the jaws and after hardening, it reached the necessary hardness. AISI 1045 steel was used for the body of the jaws, which gives us a good cost-percentage of deformation ratio, in addition, to couple the system, two mixed-conformation plates were designed, the same ones that are coupled to the machine, thus guaranteeing that the axes that support the system do not move. A load cell with acceptable sensitivity is used, which guarantees real values in the tests. A program was also generated that uses the artificial vision method to obtain the deformation data, since this measurement will be obtained from an existing comparator clock in the laboratory. In addition, this program takes the measurements of the stress that the load cell gives us and relates them to those of the deformation, and presents us with the Stress - Deformation graph. The data obtained in the tests were compared with existing data and it was verified that the stress-strain curve obtained does not show differences.