Estudio de nuevos indicadores en el dominio de la frecuencia y del tiempo para la sintonización óptima de TMDs múltiples en estructuras esbeltas

El presente Trabajo Fin de Máster se enmarca dentro de la línea de investigación sobre mitigación de vibraciones en estructuras esbeltas dirigida por el doctor Antolín Lorenzana. El trabajo se centra en desarrollar técnicas de identificación modal, de simulación y de optimización y sintonizado de TMDs, a través de la formulación del problema en el espacio de estados, y ponerlas a punto sobre estructuras a escala en laboratorio. Aunque la línea de investigación está enfocada hacia pasarelas peatonales, en este trabajo se experimenta sobre maquetas de edificios sometidas a una excitación en su base, simulando un sismo, cuidando siempre la posibilidad de extrapolar la metodología al caso de pasarelas reales. Más concretamente, durante el desarrollo del trabajo se exploran diversas formas de obtener las propiedades óptimas de TMDs diseñando y probando las diferentes funciones objetivo y haciendo uso de las capacidades en materia de optimización de Matlab. Además de los criterios tradicionales basados en los máximos de las funciones de respuesta en frecuencia, algunos criterios en el dominio del tiempo también serán analizados. Para la comparación de la bondad de las optimizaciones realizadas se emplearán dos indicadores, uno energético y otro normativo, en base a los cuales se determinará, en última instancia, qué formas son más adecuadas para lograr el mejor sintonizado de los TMDs.Departamento de Construcciones Arquitectónicas, Ingeniería del Terreno y Mecánica de los Medios Continuos y Teoría de EstructurasMáster en Ingeniería Industria

Modelos simplificados para simulación numérica (Matlab) de la acción de las personas sobre las estructuras

En el contexto del problema de la acción de los peatones sobre las estructuras, se han analizado tres modelos mecánicos sencillos con el fin de averiguar su aptitud para simular dicha carga: fuerza puntual. reproduciendo el peso del peatón; masa resorte, simulando, además, la inercia de la masa del peatón; y péndulo invertido, simulando con él los pasos.Tras la elaboración de un software en entorno Matlab se han obtenido las respuestas de la estructura (una viga) que han podido ser comparadas con la respuesta proporcionada por la guía de diseño del Sétra. Se ha comprobado que, aun cuando un solo modelo no es capaz de reproducir el mismo comportamiento, sí que lo hace combinado de forma adecuada al modelo de fuerza puntual. Así, éste proporciona una componente constante y cualquiera de los otros, la componente oscilante típica de una carga peatonal.Departamento de Construcciones Arquitectónicas, Ingeniería del Terreno y Mecánica de los Medios Continuos y Teoría de EstructurasGrado en Ingeniería Mecánic

On the estimation of the moving mass of a TMD installed on a lively structure

Producción CientíficaTuned Mass Dampers are devices which can be assimilated to single-degree-of-freedom systems with a certain amount of moving mass, a natural frequency and a damping ratio intended to be installed on lively structures to reduce the contribution of a certain mode to their response. Once placed on the structure, the movement of the mass damper couples to the structural response and determines its properties as an isolated system becomes challenging. The authors have previously presented a methodology to estimate the natural frequency and damping ratio of an SDOF system installed on a structure and not necessarily tuned to a certain mode. It was based on a transmissibility function and, thus, the moving mass could not be estimated. With this work, the authors go one step further and present a novel procedure to estimate the moving mass value by means of the same transmissibility function and two well selected frequency response functions. The methodology is applied to estimate the properties of a real single-degree-of-freedom system placed on a lively timber platform. The results are compared with the mass modification technique to show that the proposed methodology provides better estimations in a more efficient way.Ministerio de Economía, Industria y Competitividad - (project RTI2018-098425)Ministerio de Educación, Cultura y Deporte - (grant FPU16/01339

System of data recollection, analysis and transfer by NFC for transport systems

This paper shows the development and test of a prototype that collects and analyzes data of cycling trips, such as position, distance, speed, and travel time. This device was made to provide an extra security layer to the data transfer in embedded systems. The raw information that is produced by the project described in this paper is highly valued, so there is a need to record and transfer data in a secure way between electronic devices. The solution proposed in this project was based on the Near Field Communication (NFC) protocol to make the communication stage from an Electronic Control Unit to NFC tags, and then, the information stored in the tags can be read from smartphones that have an NFC module inside them. The data was generated from a Global Position System (GPS) module and antenna using the Haversine formula to calculate the distance between two geographical points, this considering the earth as a sphere to minimize the error produced taking the earth as a plane surface. A functional device that includes extra security of the data transfer in cycling trips, through NFC technology was successfully developed, however, future implementations can be extrapolated to other areas, such as the transportation sector

Measurement of acceleration response functions with scalable low-cost devices. An application to the experimental modal analysis

Producción CientíficaOne of the most popular options in the Structural Health Monitoring field is the tracking of the modal parameters, which are estimated through the frequency response functions of the structure, usually in the form of accelerances, which are computed as the ratio between the measured accelerations and the applied forces. This requires the use of devices capable of synchronously recording accelerations at several points of the structure at high sampling rates and the subsequent computational analysis using the recorded data. To this end, this work presents and validates a new scalable acquisition system based on multiple myRIO devices and digital MEMS (Micro-Electro-Mechanical System) accelerometers, intended for modal analysis of large structures. A simple form of this system was presented by the authors in a previous work, showing that a single board with some accelerometers connected to it got to obtain high quality measurements in both time and frequency domains. Now, a larger system composed by several slave boards connected and synchronized to a master one is presented. Delays lower than 100 ns are found between the synchronised channels of the proposed system. For validation purposes, a case study is presented where the devices are deployed on a timber platform to estimate its modal properties, which are compared with the ones provided by a commercial system, based on analog accelerometers, to show that similar results are obtained at a significantly lower cost.Junta de Castilla y León - FEDER (VA095P17 y VA228P20)Ministerio de Ciencia e Innovación y Ministerio de Universidades - FEDER (RTI2018-098425

6th International Conference on Mechanical Models in Structural Engineering

Producción CientíficaThis ebook contains the 37 full papers submitted to the 6th International Conference on Mechanical Models in Structural Engineering (CMMOST 2021) held in Valladolid on December 2021

Design and validation of a scalable, reconfigurable and low-cost structural health monitoring system

Producción CientíficaThis paper presents the design, development and testing of a low-cost Structural Health Monitoring (SHM) system based on MEMS (Micro Electro-Mechanical Systems) triaxial accelerometers. A new control system composed by a myRIO platform, managed by specific LabVIEW software, has been developed. The LabVIEW software also computes the frequency response functions for the subsequent modal analysis. The proposed SHM system was validated by comparing the data measured by this set-up with a conventional SHM system based on piezoelectric accelerometers. After carrying out some validation tests, a high correlation can be appreciated in the behavior of both systems, being possible to conclude that the proposed system is sufficiently accurate and sensitive for operative purposes, apart from being significantly more affordable than the traditional one.Junta de Castilla y León y Fondo Europeo de Desarrollo Regional (FEDER) - (grant VA095P17 and VA228P20

Modelos simplificados para simulación numérica (Matlab) de la acción de las personas sobre las estructuras

En el contexto del problema de la acción de los peatones sobre las estructuras, se han analizado tres modelos mecánicos sencillos con el fin de averiguar su aptitud para simular dicha carga: fuerza puntual. reproduciendo el peso del peatón; masa resorte, simulando, además, la inercia de la masa del peatón; y péndulo invertido, simulando con él los pasos.Tras la elaboración de un software en entorno Matlab se han obtenido las respuestas de la estructura (una viga) que han podido ser comparadas con la respuesta proporcionada por la guía de diseño del Sétra. Se ha comprobado que, aun cuando un solo modelo no es capaz de reproducir el mismo comportamiento, sí que lo hace combinado de forma adecuada al modelo de fuerza puntual. Así, éste proporciona una componente constante y cualquiera de los otros, la componente oscilante típica de una carga peatonal.Departamento de Construcciones Arquitectónicas, Ingeniería del Terreno y Mecánica de los Medios Continuos y Teoría de EstructurasGrado en Ingeniería Mecánic

6th International Conference on Mechanical Models in Strutural Engineering

Producción CientíficaThis document contains the Extended Abstracts submitted to the 6th Internacional Conference on Mechanical Models in Structural Engineering (CMMOST 2021) held in the Escuela de Ingenierías Industriales of the Universidad de Valladolid on December 2021

PhysEx: A novel procedure to estimate full-rank physical matrices of a structure from an incomplete modal model

Producción CientíficaThis work is devoted to presenting and applying a novel methodology that estimates a linear physical model, represented by full-rank mass, stiffness and damping matrices, capable of replicating the dynamic behaviour of an incomplete modal model. No hypothesis is made with respect to the damping matrix, so the procedure is applicable assuming any linear viscous damping model. It is shown that, if the number of considered modes satisfies a certain restriction with respect to the number of degrees of freedom, the problem has infinite solutions that differ in their exogenous eigenvalues. By controlling their effect on the dynamic behaviour of the model in the frequency range of interest, a proper final solution is obtained. The methodology is applied to a three-degrees-of-freedom discrete model and a discretized cantilever beam. Comparisons are made in both frequency and time domains which reveal that the methodology provides physical models that accurately replicate the dynamic behaviour of the incomplete modal model. Even for complete models, where the solvability condition is not met, the methodology manages to provide meaningful results in some situations. To prove the usefulness of the estimated models, a mass is added on one DOF of both examples to show that they reproduce the same effects as the original modified ones. Finally, in the interests of reproducibility, all models and algorithms presented in this article have been made publicly available.Agencia Española de Investigación - Ministerio de economía, industria y competitividad (project RTI2018-098425)Ministerio de Educación, Cultura y Deporte (grant FPU16/01339