A viscoplastic model with strain rate constitutive parameters for asphalt mixtures' response simulation

The mechanical behavior of the asphalt pavements is a complex phenomenon conditioned by the heterogeneity of the asphalt composite material. Experimental tests in the laboratory show a clear strain rate dependency in the material’s response. A new viscoplastic model has been developed to simulate de asphalt mixture’s response under dynamic loads, assuming the strain rate dependency of the material’s response observed in the experimental tests. It has been noted that the strain rate affects significantly the Young modulus and the viscosity. Taking into account this influence, a new formulation has been developed, implemented in a finite element code. The new viscoplastic model has been validated and calibrated according to laboratory test to obtain mathematical expressions for the constitutive equations. The new viscoplastic model allows us to simulate the asphalt mixture’s response, under dynamic loads and temperature variations, with a significant degree of precision, using few constitutive parameters obtained from simple experimental tests.Postprint (published version

Analysis of the effect of high heel shoes design components on gait ground reaction forces

This work is part of the activities driven by ADDfactor, Advanced Digital technologies and virtual engineering for mini-factories. This project has receied funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No. [609386].Baydal Bertomeu, JM.; Lopez Pascual, J.; Puigcerver Palau, SA.; Solves Camallonga, C.; Belda Lois, JM. (2015). Analysis of the effect of high heel shoes design components on gait ground reaction forces. Footwear Science. 7:S129-S131. https://doi.org/10.1080/19424280.2015.1038647S129S131

A Viscoplastic constitutive model with strain rate variables for asphalt mixtures’ numerical simulation

The study and development of recycling techniques for pavements is an increasing activity in engineering nowadays. This research line demands a more realistic characterization of the material properties with the aim of simulate the asphalt mixture’s response placed into a multilayered system over granular bases, under dynamic loads, considering also temperature variation or strenght reduction for cyclic loads. In order to improve the current formulations, a new viscoplastic model has been developed assuming the strain rate dependency of the material’s response observed in the experimental tests. The strain rate variable affects in a significant way the Young modulus and the viscosity parameter of the model. According to these hypothesis constitutive equations have been formulated. The mechanical variables involved have been calibrated according to experimental results, developing new expressions for the strain rate dependent parameters. The new viscoplastic model permit us to characterize the material’s response with a few mechanical values, easily obtained from standard laboratory tests. The results obtained show a good approximation to experimental laboratory curves for different rates of loading and temperatures. The model has been applied to simulate the response of a real flexible pavement structure conformed by two asphalt layers over two granular bases, that’s materials with different constitutive behaviors. Experimental tests in the recycled track have been made obtaining the horizontal strain evolution under dynamic load. Different loading rates and temperatures, as well as cracked and continuum pavement responses have been considered in the study. Strains were measured in the interface between the two asphalt layers and simulated using the here proposed model offering a fairly good approximation of the real response observed in the track, although the degree of variation even in the experimental curves is quite high. The results of this study represent a proper base for further developments in structural analysis of pavement layers, considering more complex phenomena, determinant in the long term material’s response, to develop a numerical tool for pavements’ design and lifetime prediction.Peer Reviewe

Aplicación de la programación por metas en la distribución de servicios entre empresas operadoras del sistema de transporte masivo

En este artículo se presenta una de las importantes aplicaciones que tienen los modelos de optimización dirigido hacia la distribución de servicios entre empresas operadoras del sistema de transporte masivo (SITM), esta aplicación se desarrolla mediante la programación por metas u objetivos, la cual permite obtener resultados dirigidos al cumplimiento de varias metas que proponen los entes participantes. Es así como en el desarrollo final del artículo se implementa un modelo de programación por metas al SITM Megabús obteniendo resultados óptimos para las dos empresas operadoras con base a sus objetivos previamente establecidos

Real time motion estimation using a neural architecture implemented on GPUs

This work describes a neural network based architecture that represents and estimates object motion in videos. This architecture addresses multiple computer vision tasks such as image segmentation, object representation or characterization, motion analysis and tracking. The use of a neural network architecture allows for the simultaneous estimation of global and local motion and the representation of deformable objects. This architecture also avoids the problem of finding corresponding features while tracking moving objects. Due to the parallel nature of neural networks, the architecture has been implemented on GPUs that allows the system to meet a set of requirements such as: time constraints management, robustness, high processing speed and re-configurability. Experiments are presented that demonstrate the validity of our architecture to solve problems of mobile agents tracking and motion analysis.This work was partially funded by the Spanish Government DPI2013-40534-R grant and Valencian Government GV/2013/005 grant

Análisis factorial con componentes principales para interpretacion de imágenes satelitales “landsat tm 7” aplicado en una ventana del departamento de risaralda

En este artículo se presenta una de las múltiples ventajas que trae consigo el análisis multivariante de datos, mostrando como a partir de la técnica de análisis factorial con componentes principales como método de extracción se pueden mejorar las imagen satelitales utilizadas en la exploración de áreas geográficas con el objetivo de identificar claramente la ubicación específica de ciertos materiales naturales como carbón y otros minerales