Diseño y construcción de mordazas para realizar ensayos a tracción en tubos de acero y cañerías de cobre en la máquina universal del laboratorio de resistencia de materiales de la Escuela de Ingeniería Mecánica -ESPOCH.

Abstract

Due to the updating of the regulations related to quality control for the production of pipes in the steel industry, a set of clamps (4 molars) was designed and built to be used in the universal machine, located in the Material Resistance Laboratory of the Mechanical Engineering School at the ESPOCH; additional, a laboratory guide was also developed. This is to perform traction tests on steel and copper pipes. For the design, a range of external diameters of specimen 1 in to 5/16 in, was taken into account of different thicknesses, in samples with a maximum length of one meter of pipe. The state of the art has been revised in depth to know all aspects of functionality and certainty that the clamps must meet. Next, the most appropriate shape option is chosen according to pre-stablished parameters and all the efforts that will support are calculated, as well as the final measures with an acceptable safety range. An analysis software of finite and modeling elements were used to validate the previous work. For the construction, it begins with a Cr-Mn alloyed steel, suitable to make a subsequent superficial hardening, necessary to guarantee the accessory quality, which provides a method to make them. It is recommended to be very thorough in the design process, considering all the forces that act at the time of conducting the test, so not to have any inconvenience with the geometry dimensions and to avoid any kind of failures.