Finite element modeling of energy harvesters: application to vibrational devices

[ES] En este capítulo se presenta el conjunto de ecuaciones de gobierno para estudiar el comportamiento de los materiales activos, los cuales tienen una capacidad intrínseca para acoplar varias ramas de la Física y, en consecuencia, son comúnmente utilizados para la fabricación de cosechadoras. Una vez definidas las ecuaciones, se desarrolla una formulación numérica basada en el método de los elementos finitos para modelar estos materiales. En particular, en este capítulo se estudia la producción de energía a partir de las vibraciones mecánicas presentes en puentes ferroviarios de alta velocidad. Para ello, se hace un repaso de los parámetros básicos de estos puentes, sus vibraciones, frecuencias y las características dinámicas. A continuación, se simulan cosechadores en voladizo fabricados con materiales piezoeléctricos y piezomagnéticos bajo vibraciones mecánicas típicas y se destacan varias conclusiones.[EN] This chapter presents the set of governing equations to study the behavior of active materials, which have an intrinsic ability for coupling several branches of Physics and, consequently, are commonly used for manufacturing harvesters. Once the equations are defined, a numerical formulation based on the finite element method is developed in order to model these materials. In particular, this chapter studies the energy production from mechanical vibrations present in high-speed railway bridges. For this purpose, a review of the basic parameters of these bridges, their vibrations, frequencies and the dynamic characteristics are highlighted. Then, cantilever harvesters made out of piezoelectric and piezomagnetic materials are simulated under typical mechanical vibrations and several conclusions are highlighted.Palma, R.; Pérez-Aparicio, JL.; Museros Romero, P. (2018). Finite element modeling of energy harvesters: application to vibrational devices. En Energy Harvesting for Wireless Sensor Networks: Technology, Components and System Design. De Gruyter. 3-33. https://doi.org/10.1515/9783110445053-00133

Analysing Food-Porn Images for Users’ Engagement in the Food Business

Ponència presentada a 24th International Conference of the Catalan Association for Artificial Intelligence, celebrada a Barcelona en 2022.This paper presents an approach for analysing food-porn images and their related comments published by the cooking school Getcookingcanada Instagram account. Our approach processes the published images to extract colour parameters, counts the number of likes, and also analyses the comments related to each publication. A dataset containing all these was built, and methods were applied to study correlations among the data: a regression analysis, an ANOVA and a sentiment analysis of the comments on the dataset to explain the relation between the quantity of likes and the sentiment obtained from the food images. Our results show a correlation between the number of likes and the sentiment analysis of the comments. Images that evoke a positive sentiment have a higher number of likes and comments. Users’ experience on creating posts is also analysed and confirms a positive correlation between the number of likes and the publisher’s experience

Measures of Similarity Between Objects Based on Qualitative Shape Descriptions

A computational approach for comparing qualitative shape descriptions (QSDs) of objects within digital images is presented. First, the dissimilarity of qualitative features of shape is measured: (i) intuitively using conceptual neighbourhood diagrams; and (ii) mathematically using interval distances. Then, a similarity measure between QSDs is defined and tested using images of different categories of the MPEG-7-CE-Shape-1 library, images of tiles used to build mosaics, and a collection of Clipart images. The results obtained show the effectiveness of the similarity measure defined, which is invariant to translations, rotations and scaling, and which implicitly manages deformation of shape parts and incompleteness

Studying the Role of Location in 3D Scene Description using Natural Language

Kluth T, Falomir Z. Studying the Role of Location in 3D Scene Description using Natural Language. In: Sanz I, Museros L, Ortega JA, eds. XV Jornadas de la Asociación de Razonamiento Cualitativo y Aplicaciones (JARCA '13). Sistemas Cualitativos y sus Aplicaciones en Diagnosis, Robótica e Inteligencia Ambiental. Murcia, Spain: Proceedings from the University of Seville; 2013.In this paper the description of 3D indoor scenes in natural language is studied from the point of view of intrinsic and relative location of the objects. An approach has been developed for this purpose which uses a XBox 360 Kinect in combination with ROS and PCL to obtain 3D-data from the scene. Object features are computed on these 3D-data, which are used to generate a SVM-model which classifies the different objects in the scene. After detecting the objects in the scene, their orientation is obtained and qualitative spatial relations between the objects are computed to generate a natural-language description of the scene

Study of Vibrations in a Short-Span Bridge Under Resonance Conditions Considering Train-Track Interaction

[EN] Resonance is a phenomenon of utmost importance in railways engineering, leading to vast damages both in track and vehicles. A short-span bridge has been modeled by means of a finite elements method model, calibrated and validated with real data, to study resonance vibrations induced by the passage of trains. Furthermore, the influence of vehicle speed and track damping on the vibrations registered on the rail, the sleeper and the bridge has been assessed. Different track and vehicle pathologies have been proposed and their effect on the resonance of the bridge has been evaluated.Ribes-Llario, F.; Velarte-González, JL.; Pérez-Garnes, JL.; Real Herráiz, JI. (2016). Study of Vibrations in a Short-Span Bridge Under Resonance Conditions Considering Train-Track Interaction. Latin American Journal of Solids and Structures. 13(7):1236-1249. doi:10.1590/1679-78252773S12361249137Ahlström, J., & Karlsson, B. (1999). Microstructural evaluation and interpretation of the mechanically and thermally affected zone under railway wheel flats. Wear, 232(1), 1-14. doi:10.1016/s0043-1648(99)00166-0Bian, X., Chao, C., Jin, W., & Chen, Y. (2011). A 2.5D finite element approach for predicting ground vibrations generated by vertical track irregularities. Journal of Zhejiang University-SCIENCE A, 12(12), 885-894. doi:10.1631/jzus.a11gt012Grassie, S. L., & Kalousek, J. (1993). Rail Corrugation: Characteristics, Causes and Treatments. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 207(1), 57-68. doi:10.1243/pime_proc_1993_207_227_02Gupta, A., & Singh Ahuja, A. (2014). Dynamic Analysis of Railway Bridges under High Speed Trains. Universal Journal of Mechanical Engineering, 2(6), 199-204. doi:10.13189/ujme.2014.020604Ju, S. H., & Lin, H. T. (2003). Resonance characteristics of high-speed trains passing simply supported bridges. Journal of Sound and Vibration, 267(5), 1127-1141. doi:10.1016/s0022-460x(02)01463-3Kwark, J. W., Choi, E. S., Kim, Y. J., Kim, B. S., & Kim, S. I. (2004). Dynamic behavior of two-span continuous concrete bridges under moving high-speed train. Computers & Structures, 82(4-5), 463-474. doi:10.1016/s0045-7949(03)00054-3Lu, Y., Mao, L., & Woodward, P. (2012). Frequency characteristics of railway bridge response to moving trains with consideration of train mass. Engineering Structures, 42, 9-22. doi:10.1016/j.engstruct.2012.04.007Makino, T., Yamamoto, M., & Fujimura, T. (2002). Effect of material on spalling properties of railroad wheels. Wear, 253(1-2), 284-290. doi:10.1016/s0043-1648(02)00117-5Mao, L., & Lu, Y. (2013). Critical Speed and Resonance Criteria of Railway Bridge Response to Moving Trains. Journal of Bridge Engineering, 18(2), 131-141. doi:10.1061/(asce)be.1943-5592.0000336Museros, P., Romero, M. ., Poy, A., & Alarcón, E. (2002). Advances in the analysis of short span railway bridges for high-speed lines. Computers & Structures, 80(27-30), 2121-2132. doi:10.1016/s0045-7949(02)00261-4Pal, S., Valente, C., Daniel, W., & Farjoo, M. (2012). Metallurgical and physical understanding of rail squat initiation and propagation. Wear, 284-285, 30-42. doi:10.1016/j.wear.2012.02.013Sheng, X., Jones, C. J. C., & Thompson, D. J. (2004). A theoretical model for ground vibration from trains generated by vertical track irregularities. Journal of Sound and Vibration, 272(3-5), 937-965. doi:10.1016/s0022-460x(03)00782-xSimon, S., Saulot, A., Dayot, C., Quost, X., & Berthier, Y. (2013). Tribological characterization of rail squat defects. Wear, 297(1-2), 926-942. doi:10.1016/j.wear.2012.11.011Wang, Y., Wei, Q., Shi, J., & Long, X. (2010). Resonance characteristics of two-span continuous beam under moving high speed trains. Latin American Journal of Solids and Structures, 7(2), 185-199. doi:10.1590/s1679-78252010000200005Xia, H., Zhang, N., & Guo, W. W. (2006). Analysis of resonance mechanism and conditions of train–bridge system. Journal of Sound and Vibration, 297(3-5), 810-822. doi:10.1016/j.jsv.2006.04.022Yang, Y. B., & Lin, C. W. (2005). Vehicle–bridge interaction dynamics and potential applications. Journal of Sound and Vibration, 284(1-2), 205-226. doi:10.1016/j.jsv.2004.06.03