Diseño y construcción de mordazas planas para realizar ensayos a tracción en la máquina universal del laboratorio de resistencia de materiales de la Facultad de Mecánica

Abstract

To comply with national and international standards that impose the norms for the moment of carrying out tensile tests, it was performed the design and construction of a set of four clamps necessary for the universal machine located in the Laboratory of Resistance of Materials of the Mechanics Career of the Escuela Superior Politécnica Chimborazo. This project was generated through a reverse engineering process, considering the dimensions of the square section specimens used by the original jaws, from this a study was generated using Computer Aided Design software, in order to obtain data on the correct selection of material for the new jaws, in this way a redesign was generated based on the invariable parameters of the original design, consecutively the calculation of the efforts to which the project will be subjected was carried out, considering an acceptable safety factor. The result was verified by simulation in the finite element analysis software, thus the previously performed calculations were validated. For the construction process, a chromium manganese alloy steel was used, which had to be subjected to a normalized heat treatment, reducing its hardness levels, and it facilitated its machinability. Once this process was generated, it was proposed to partially recover the hardness by means of the superficial thermal treatment of carbonitriding reaching values similar to those of a commercial steel. Finally, tests were carried out to verify its level of hardness and it was found that the reaction of the jaws was positive in the tensile test, it was obtained a very useful accessory with a high level of quality.