Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Application of a Cobot to measure the coefficient of friction of pairs of materials(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06-13) Reyes Brito, Ali Abigail; Farfán Cabrera, Leonardo Israel; emipsanchez; Galluzzi Aguilera, Renato; School of Engineering and Sciences; Campus Ciudad de México; Hernández Peña, AndysSince the earliest inventions of tools to the development of complex machinery for production lines, humans have consistently pursued the goal of achieving better products with minimal energy consumption. In this quest for efficiency, they began to study physical phenomena such as friction, wear, and lubrication. These studies gave rise to a branch of science known as tribology. Within this field, significant interest emerged in analyzing the behavior of frictional forces and, consequently, the coefficients of friction (CoF) generated between two contacting surfaces in relative motion. Understanding these interactions enables more informed decisions in the selection of materials, coatings, and lubricants to ensure adequate motion transmission, improve system performance, extend component lifespan, enhance efficiency, and reduce energy consumption. To study friction coefficients under specific tribological conditions, specialized machines called tribometers were developed. The wide range of contact configurations, motion types, and wear mechanisms required for testing led to the creation of various tribometer models. However, existing tribometers often require modifications or custom setups to meet the evolving demands of tribological research, especially for tests involving non-standard motion paths. In addition, as research advances the need has grown for faster yet reliable testing methods and for accessible solutions that allow friction measurements to be performed directly at the testing site. This research evaluates the use of the UR5e collaborative robot (Cobot) as a reliable alternative for on-site friction testing under non-conventional motion conditions that are not typically addressed by traditional tribological test benches. The study was divided into two main approaches: the first, conduct standard pin-on-disk tests in dry, room-temperature conditions, following ASTM G99 norm; the second, perform tests using a custom sinusoidal slide path. For both testing approaches, three pairs of materials were tested (steel/aluminum, steel/steel, and steel/wood), a specialized end-effector was designed, and force and velocity data were acquired using the Cobot’s internal sensors. The friction data obtained by Cobot were compared and correlated with those gathered from the parallel pin-on-disk experiments. Additionally, this work discusses the findings, behavioral differences, potential sources of error, limitations, and future perspectives regarding the use of Cobots in tribological testing.
- Electrified tribological study of bio-derived lubricants for electromobility applications(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024-11-03) Rubio Hernández, Carlos Cristóbal; Farfán Cabrera, Leonardo Israel; emipsanchez; Reséndiz Calderón, César David; Vázquez Lepe, Elisa Virginia; School of Engineering and Sciences; Campus Ciudad de México; Hernández Peña, AndysClimate change has forced humanity to develop less harmful alternatives to the environment. Electromobility has then increased in popularity, aiming for humankind's greener and climate-neutral future. Nevertheless, the complete change in the vehicles’ driveline caused different complexities, including tribological problems; therefore, new lubricants should fulfill the requirements needed in the XXI century’s transportation. Moreover, stray currents and induced voltage are inevitable. Hence, new lubricants must have good electric properties that do not hinder their lubricity capability due to these harsher conditions. In addition, conventional lubricants and their additives harm the environment and human health during production, usage, and disposal. A considerable amount of used lubricants end up polluting different ecosystems and potentially affecting biodiversity and health. If the power source of vehicles is becoming greener, so should their components, and the lubricants are not an exception. Bio-based lubricants come from renewable resources, are biodegradable, and are less toxic to the environment and human interaction. Nevertheless, not all bio-lubricants can be considered sustainable since they could give rise to a conflict, economic and ethical, with food production. This research evaluates the performance of two non-edible bio-based lubricants, neat Jatropha curcas, and Micro-algae oils, and used them as additives of Mineral Group II and synthetic PAO 4 oils, respectively, at low volumetric concentrations of 5 and 10%, by characterizing their physicochemical properties and assessing their tribological performance in a four-ball tester, which was modified to run electrified trials to emulate the conditions in which they would operate in an electric vehicle’s powertrain.
- Tribological evaluation of a graphene-based lubricant in metal-on-metal and wet clutch interfaces(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06-11) Cao Romero Gallegos, Julio Alberto; Farfán Cabrera, Leonardo Israel; puemcuervo; Reséndiz Calderón, César David; Medina Medina, Dora Iliana; Escuela de Ingeniería y Ciencias; Campus Estado de MéxicoCertain nanoparticles have been consistently demonstrated to exhibit remarkable lubricant improvements as used as additives. In particular, graphene nanosheets (GNS) added to lubricating oils have shown significant reduction of wear and coefficient of friction (CoF) in a wide range of metallic interfaces for different applications. Wet clutches from automatic transmissions are lubricated with high-performance automatic transmission fluid (ATF). Their efficiency, in terms of torque transmission by friction, depends on the tribological behavior of both the wet clutch sliding plates and ATF. However, commercial ATFs need continuous enhancement to comply new and more stringent OEM requirements. One of those requirements is to maintain the short- and long-term antishudder property of ATFs. This property, which is represented by a friction coefficient increasing with sliding speed, helps to keep reduced vibrations during clutch engagements and lock-up stages in the transmission, which is needed for driving comfort and increased durability of involved components in the transmission. Considering the tribological effectiveness of GNS in lubricants for reducing friction and wear, it can be a suitable additive for improving the antishudder property of ATFs. Although GNS have been largely studied as additives in lubricants for several metallic interfaces, their effects on wet clutches interfaces have been scarcely studied. Thus, this thesis contributes with an assessment of the tribological (friction and wear) behavior of graphene-based oils (blends of mineral base oil + GNS) at different concentrations in metal-on-metal contacts and the CoF behavior with speed (antishudder representation) in a wet clutch interphase using a pin-on-disc tester. The tests ran in metal-on-metal interfaces confirmed a significant wear rate reduction with unaltered CoF in aluminum and steel when a mineral oil with 1.0 wt.% GNS concentration was used in tests. In addition, the CoF of the wet clutch was reduced in general, while the antishudder property was enhanced by the addition of 1.0 wt.% GNS to the mineral oil.