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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- Auxetic lattice sensor for In-socket load evaluation(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022) Ramírez Gutiérrez, Diana Laura; RAMIREZ GUTIERREZ, DIANA LAURA; 883618; Cuan Urquizo, Enrique; puelquio/mscuervo; Román Flores, Armando; Navarro Gutiérrez, Manuel; Escuela de Ingeniería y Ciencias; Campus Monterrey; Fuentes Aguilar, Rita QuetziquelAuxetic metamaterials present an uncommon dome shape when subjected to an out-of-plane bending moment, known as synclasticity. This property has them potential candidates in aerospace, biomedical and textiles. Currently, the use of wearable devices has increased. These sensors allow the tracking of physical activity of the human body, which provide useful information about health. They need to withstand repeated large deformations and conform to the complex curved geometries of the human body without loss in performace. Conformability has presented a challenge in materials science and engineering and one approach to overcome this, has been the implementation of auxetic topologies. Still, most applications remain in their infancy and require more research. Despite biomedical sensors being subjected to complex loading conditions, most of the literature has focused on auxetic metamaterials under simple tensile and compressive loadings. The geometrical parameter-Poisson´s ratio was thoroughly characterized bia Finite element modeling (FEM). This brought up a thorough relation between their geometrical parameters and auxeticity. Their out-of-plane stiffness was also characterized via FEM and corroborated with additive manufactured samples subjected to the same boundary conditions. A conformability ratio was computed with digital image processing, and a generalized linear model of 95% confidence interval exhibited the relation between each parameter and this property. Topologies with similar conformability ratio were found, which allowed to establish a relation between geometrical parameters, conformability and stiffness. Finally, the fabrication of pressure-sensing devices was achieved by the instrumentation of velostat with different auxetic porous arrangements. This exposed a general view of their electric response under different loading conditions. These devices were also tested as in-socket pressure sensors, establishing a link between their electric and mechanical response while being stretched to conform an artificial residual limb. This, in addition to in-plane, and out-of-plane characterization, lead to key properties when deciding the geometry specific for applications; deformation mechanism, relative density, auxetic behavior and stiffness.
- Novel Bézier-based metamaterials: synthesis, mechanics and additive manufacturing(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06-04) Álvarez Trejo, Alberto; CUAN URQUIZO, ENRIQUE; 345654; Cuan Urquizo, Enrique; emipsanchez; Alvarado Orozco, Juan Manuel; Farfán Cabrera, Leonardo Israel; Olvera Silva, Oscar; Escuela de Ingeniería y Ciencias; Campus Monterrey; Román Flores, ArmandoThe design of mechanical metamaterials often uses lattice arrangements being benefited from the increase in Additive Manufacturing technologies available. Such design freedom allows the fabrication of lattice arrangements with complex curved geometries. Here we propose a whole family of novel lattice matematerials parametrized using cubic Bézier curves. The methodology presented permits the generation of unit cells with different degrees of curvature based on the location of the Bézier control points along a spiral. The apparent stiffness of these structures was characterized using finite element analysis (FEA) and compression tests on additively manufactured samples using stereolithography (SLA). The mechanical properties of spiral based cubic Bézier (SBCB) metamaterials were related to the location of the control points. The methodology was expanded to generate metamaterials with porosity in the three orthogonal planes, and the apparent stiffness of these structures was obtained by FEA. The procedure presented for the synthesis of metamaterials enables the generation of structures with customized mechanical properties by adjusting the geometry of the unit cells. The apparent stiffness of both 2D and 3D SBCB metamaterials from simulation was compared to existing metamaterials,defining a design region that is limited by manufacturing and geometry conditions.