A BEM based on the Bézier/Bernstein polynomial for acoustic waveguide modelization

42nd International Conference on Boundary Elements and other Mesh Reduction Methods, BEM/MRM 2019; ITeCons-University of CoimbraCoimbra; Portugal; 2 July 2019 through 4 July 2019; Code 155806. Publicado en WIT Transactions on Engineering Sciences, Vol 126This paper proposes a novel boundary element approach formulated on the Bézier–Bernstein basis to yield a geometry-independent field approximation. The proposed method is geometrically based on both computer aided design (CAD) and isogeometric analysis (IGA), but field variables are independently approximated from the geometry. This approach allows the appropriate approximation functions for the geometry and variable field to be chosen. We use the Bézier–Bernstein form of a polynomial as an approximation basis to represent both geometry and field variables. The solution of the element interpolation problem in the Bézier–Bernstein space defines generalised Lagrange interpolation functions that are used as element shape functions. The resulting Bernstein–Vandermonde matrix related to the Bézier–Bernstein interpolation problem is inverted using the Newton–Bernstein algorithm. The applicability of the proposed method is demonstrated by solving the Helmholtz equation over an unbounded region in a two-and-a-half dimensional (2.5D) domain.Ministerio de Economía y Competitividad BIA2016-75042-C2-1-

Arte y mundo hoy: Acerca de la vigencia de la meditación heideggeriana sobre la obra de arte

La interpretación del arte de Heidegger destaca por su radicalidad y originalidad. Para el pensador alemán, la esencia del arte se mantendrá oculta mientras no se ponga en conexión dicha actividad productiva con la pregunta por el ser. Al proceder así, se nos revela, por un lado, la constitutiva dimensión ontológica del arte y su íntima vinculación con el fenómeno de la verdad y, por otro, la insuficiencia de los tradicionales planteamientos sobre el arte y de la estética como disciplina filosófica. ¿Continúa vigente dicho planteamiento ontológico?, ¿es compatible con las nuevas condiciones de la producción artística emergentes en el actual mundo científico-técnico

Hermenéutica y subjetividad.

Sin resume

Low weight additive manufacturing FBG accelerometer: design, characterization and testing

Structural Health Monitoring is considered the process of damage detection and structural characterization by any type of on-board sensors. Fibre Bragg Gratings (FBG) are increasing their popularity due to their many advantages like easy multiplexing, negligible weight and size, high sensitivity, inert to electromagnetic fields, etc. FBGs allow obtaining directly strain and temperature, and other magnitudes can also be measured by the adaptation of the Bragg condition. In particular, the acceleration is of special importance for dynamic analysis. In this work, a low weight accelerometer has been developed using a FBG. It consists in a hexagonal lattice hollow cylinder designed with a resonance frequency above 500 Hz. A Finite Element Model (FEM) was used to analyse dynamic behaviour of the sensor. Then, it was modelled in a CAD software and exported to additive manufacturing machines. Finally, a characterization test campaign was carried out obtaining a sensitivity of 19.65 pm/g. As a case study, this paper presents the experimental modal analysis of the wing of an Unmanned Aerial Vehicle. The measurements from piezoelectric, MEMS accelerometers, embedded FBGs sensors and the developed FBG accelerometer are compared.Ministerio de Economía y Competitividad BIA2013-43085-P y BIA2016-75042-C2-1-

La noción de infinito desde el horizonte de las filosofías de la finitud

La noción de infinito, considerada desde una perspectiva ontológica, constituye el tema del presente artículo. El propósito es reflexionar sobre el singular planteamiento que la filosofía contemporánea ha desplegado en torno a esa idea, y que ha provocado una profunda modificación del enfoque filosófico tradicional de la oposición finitud-infinitud. Un nuevo enfoque con decisivas influencias en los distintos ámbitos de la filosofía: antropología, teología, epistemología…The notion of infinite, considered from an ontological perspective, constitutes the topic of the present article. The intention is to think about the singular exposition that the contemporary philosophy has opened concerning this idea, ant that has provoked a deep modification of the philosophical traditional approach of the opposition finity-infinity. A new approach with decisive influences in the different areas of the philosophy and of other disciplines to her linked: anthropology, theology..

A 2.5D BEM-FEM using a spectral approach to study scattered waves in fluid–solid interaction problems

42nd International Conference on Boundary Elements and other Mesh Reduction Methods, BEM/MRM 2019; ITeCons-University of Coimbra, Coimbra; Portugal; 2 July 2019 through 4 July 2019. - Publicado en WIT Transactions on Engineering Sciences, Volume 126, 2019, Pages 111-123This work presents a two-and-a-half dimensional (2.5D) spectral formulation based on the finite element method (FEM) and the boundary element method (BEM) to study wave propagation in acoustic and elastic waveguides. The analysis involved superposing two dimensional (2D) problems with different longitudinal wavenumbers. A spectral finite element (SFEM) is proposed to represent waveguides in solids with arbitrary cross-section. Moreover, the BEM is extended to its spectral formulation (SBEM) to study unbounded fluid media and acoustic enclosures. Both approaches use Lagrange polynomials as element shape functions at the Legendre–Gauss–Lobatto (LGL) points. The fluid and solid subdomains are coupled by applying the appropriate boundary conditions at the limiting interface. The proposed method is verified by means of a benchmark problem regarding the scattering of waves by an elastic inclusion. The convergence and the computational effort are evaluated for different h-p strategies. Numerical results show good agreement with the reference solution. Finally, the proposed method is used to study the pressure field generated by an array of elastic fluid-filled scatterers immersed in an acoustic mediumMinisterio de Economía y Competitividad BIA2016-75042-C2-1-

Design and implementation of a low-power low-cost smart embedded system for remote animal monitoring

This Master’s thesis serves as the foundation for an innovative wildlife monitoring system, encompassing hardware design, firmware and software development, and offering insights into future directions. Leveraging the research group’s extensive experience in research, development, and field deployment of wildlife technology solutions, the thesis has culminated in a device with versatile capabilities suitable for a wide range of applications. A central focus of this work is on energy efficiency, prioritizing low-power operation to facilitate extended field deployments and reduce maintenance requirements. The integration of AI capabilities is a core component, enabling real-time data analysis within the embedded system. The system’s architecture is thoughtfully designed to seamlessly integrate data from diverse sources, including visual, acoustic, and environmental inputs, providing comprehensive insights into the natural world. Modularity in communication networks empowers the system to adapt to varying project requirements and network environments. The successful integration of hardware and software components enhances system performance, ensuring seamless data flow and efficient communication between different modules. The thesis underscores the importance of comprehensive testing, performance characterization, and real-world field testing for future research. In summary, this work represents a crucial step in the development of a versatile, energy-efficient, and AI-enhanced wildlife monitoring system with the potential to make substantial contributions to the field of conservation technology.Universidad de Sevilla. Máster Universitario en Microelectrónica: Diseño y Aplicaciones de Sistemas Micro/Nanométrico

Dynamic study of the Barqueta cable-stayed Bridge

Proceedings of a meeting held 30 January - 2 February 2006, St Louis, Missouri, USA. http://toc.proceedings.com/00102webtoc.pdf Vol. 1A theoretical and experimental research work of the Barqueta cable-stayed bridge is described in this paper. The Barqueta Bridge, across Guadalquivir river, links the city of Seville with the Scientific Park Cartuja 93. At jam hours cars may cover one half of the bridge lanes for more than one hour. Full-scale tests were carried out to measure the bridge dynamic response. The experimental program includes the dynamic study for both cases: the bridge with one half of it lanes full of cars, and empty. Modal parameters estimations were made based on the acquired data. Ten vibration modes have been identified in the frequency range of 0-6 Hz by different techniques, being two of these modes very close to each other. The traffic-structure interaction is also studied. The experimental results were compared with those obtained from a three-dimensional finite element model developed in this work. Both sets of results show very good agreement. Finally, a damage identification technique has been applied to determine the integrity of the structureMinisterio de Educación y Ciencia BIA2004-03955-C02-0

A novel 2.5D spectral approach for studying thin-walled waveguides with fluid-acoustic interaction

This paper presents a novel formulation of two spectral elements to study guided waves in coupled problems involving thin-walled structures and fluid-acoustic enclosures. The aim of the proposed work is the development of a new efficient computational method to study problems where geometry and properties are invariant in one direction, commonly found in the analysis of guided waves. This assumption allows using a two-and-a-half dimensional (2.5D) spectral formulation in the wavenumber-frequency domain. The novelty of the proposed work is the formulation of spectral plate and fluid elements with an arbitrary order in 2.5D. A plate element based on a Reissner-Mindlin/Kirchhoff-Love mixed formulation is proposed to represent the thin-walled structure. This element uses approximation functions to overcome the difficulties to formulate elements with an arbitrary order from functions. The proposed element uses a substitute transverse shear strain field to avoid shear locking effects. Three benchmark problems are studied to check the convergence and the computational effort for different strategies. Accurate results are found with an appropriate combination of element size and order of the approximation functions allowing at least six nodes per wavelength. The effectiveness of the proposed elements is demonstrated studying the wave propagation in a water duct with a flexible side and an acoustic cavity coupled to a Helmholtz resonator.Ministerio de Economía y Competitividad BIA2013-43085-P y BIA2016-75042-C2-1-RCentro Informático Científico de Andalucía (CICA

Identificación de daños en estructuras a partir de su respuesta dinámica

Trabajo reproducido y difundido en el repositorio idUS con permiso de la Asociación Española de Ingeniería Mecánica (AEIM)La presencia de daños en estructuras puede deberse a multitud de causas. Por ejemplo, debido a causas accidentales que excedieron aquellas para las cuales fueron diseñadas las estructuras o simplemente porque éstas han superado su vida útil. La presencia de un daño en un sistema mecánico implica un cambio en las propiedades dinámicas del mismo. Por tanto, la detección del dafio mediante la variación de las propiedades dinámicas tiene un gran interés, sobre todo en los casos en que los defectos están en partes de la estructura que no son accesibles. Este trabajo pretende dar una visión general de los métodos de detección y localización del daño en estructuras más usados en la actualidad, profundizando en alguno de ellos y probándolos en un banco de ensayos creado al efecto en el Laboratorio de Teoría de Estructuras de la Escuela Técnica Superior de Ingenieros de la Universidad de SevillaAppearance of damages in structures is due to several reasons. For instance, accidental causes that exceed design considerations. Damages in mechanical systems provoke changes in their dynamic properties. Therefore, damage detection by the variation of dynamic properties has a huge interest, especially in cases where damages are in non-accessible areas. This work expects to show briefly the existing methods to identify and locate damages in structures, dealing with sorne of them and testing them in a test device created in the Structures laboratory of Escuela Técnica Superior de Ingenieros (University of Seville)