Search results for " Mechanical engineering"
showing 10 items of 623 documents
A Multilayered Plate Theory with Transverse Shear and Normal Warping Functions
2016
A multilayered plate theory which takes into account transverse shear and normal stretching is presented. The theory is based on a seven-unknowns kinematic field with five warping functions. Four warping functions are related to the transverse shear behaviour, the fifth is related to the normal stretching. The warping functions are issued from exact three-dimensional solutions. They are related to the variations of transverse shear and normal stresses computed at specific points for a simply supported bending problem. Reddy, Cho-Parmerter and (a modified version of) Beakou-Touratier theories have been retained for comparisons. Extended versions of these theories, able to manage the normal s…
Radio environment map estimation based on communication cost modeling for heterogeneous networks
2017
Los mapas del entorno radioeléctrico pueden ser una poderosa herramienta para lograr una asignación de recursos eficiente y consciente del contexto en las redes heterogéneas 5G. En este trabajo, consideramos una red heterogénea formada por una red celular tradicional y una red de sensores inalámbricos. El papel de la red de sensores inalámbricos es estimar el mapa del entorno radioeléctrico de la célula utilizando una técnica de interpolación geoestadística denominada Kriging. En un trabajo anterior se propuso un algoritmo de agrupación distribuida de sensores para reducir la complejidad de la estimación. En nuestra contribución, el proceso de formación de clústeres se modifica para incluir…
Distributed radio map reconstruction for 5G automotive
2018
Se espera que los mapas de entorno radio sean una herramienta esencial para la optimización y gestión de recursos del 5G en vehículos. En este trabajo, consideramos el problema de la reconstrucción del mapa de entorno radio utilizando una red de sensores inalámbricos formada por nodos sensores en vehículos, nodos de acceso de una infraestructura de ciudad inteligente, etc. Debido a las limitaciones de recursos en las redes de sensores, es crucial seleccionar un pequeño número de mediciones de los sensores para reconstruir el campo. En este contexto, presentamos un novedoso algoritmo distribuido basado en el método de regresión Kriging para la reconstrucción del mapa de entorno radio en térm…
Stress-strain analysis of specimens subjected to tensile loading during moisture uptake
2015
Abstract: A robust and efficient numerical method for the calculation of the internal stress state that develops within structures subjected to mechanical and steady state or transient hygroscopic loading conditions, has been developed. The method encompasses a layer by layer approach whereby the structure is discretised into plies with different material properties corresponding to the different ply moisture content. The proposed method has been validated against finite element solutions, and results from its application on a fully characterised EDT (technical name) polymer binder are presented. The impact of the moisture induced viscoelastic behaviour on the structural response of the cas…
MDP-Based Resource Allocation Scheme Towards a Vehicular Fog Computing with Energy Constraints
2018
As mobile applications deliver increasingly complex functionalities, the demands for even more intensive computation would quickly transcend energy capability of mobile devices. On one hand and in an attempt to address such issues, fog computing paradigm is introduced to mitigate the limited energy and computation resources available within constrained mobile devices, by moving computation resources closer to their users at the edge of the access network. On another hand, most of electric vehicles (EVs), with increasing computation, storage and energy capabilities, spend more than 90% of time on parking lots. In this paper, we conceive the basic idea of using the underutilized computation r…
Proportional and Preemption-Enabled Traffic Offloading for IP Flow Mobility: Algorithms and Performance Evaluation
2018
IP Flow Mobility (IFOM) enables a user equipment to offload data traffic at the IP flow level. Although the procedure of IFOM-based flow offloading has been specified by 3GPP, how many IP flows should be offloaded and when offloading should be performed are not defined. Consequently, IP flows may be routed to a target access network which has a strong signal strength but with backhaul congestion or insufficient access capability. In this paper, we propose two algorithms, referred to as proportional offloading (PO), and proportional and preemption-enabled offloading (PPO), respectively, for IP flow offloading in hybrid cellular and wireless local area networks. The PO algorithm decides an op…
Complex power distribution analysis in plates covered with passive constrained layer damping patches
2012
International audience; The vibration of a plate partially covered with a passive constrained layer damping (PCLD) patch is studied from an energetic point of view. The damped plate is excited by an acoustic plane wave. The study is done with a numerical two-dimensional multilayer plate model. Results of the present model are compared to those obtained with three-dimensional finite element models. It is shown that the present model gives accurate results, even for the layer's inner behavior. It is less expansive in terms of computational cost; hence, it can simulate efficiently the structure for higher frequencies. Mathematical formulas for complex mechanical power are presented, and the li…
Alpha-amylase serum levels in professional soccer players are not related with physical fitness.
2017
Backgorund Recent evidence has showed that serum or salivary values of α-amylase predict endurance running performance. In this study we investigate whether serum α-amylase concentration may be associated with training status during a competitive season and after a detraining period in professional soccer players. Methods The study population consisted in 15 male professional soccer players from an Italian major league team (age [mean±SD] 27±5 years, weight 76.9±4.1 kg, height 1.82±0.05 m). Serum α-amylase levels were measured 3 times during the last part of a competitive season (January, March and May) and just before preseason training (July). Results Metabolic and cardiovascular fitness …
Computational Analysis of the Active Control of Incompressible Airfoil Flutter Vibration Using a Piezoelectric V-Stack Actuator
2021
The flutter phenomenon is a potentially destructive aeroelastic vibration studied for the design of aircraft structures as it limits the flight envelope of the aircraft. The aim of this work is to propose a heuristic design of a piezoelectric actuator-based controller for flutter vibration suppression in order to extend the allowable speed range of the structure. Based on the numerical model of a three degrees of freedom (3DOF) airfoil and taking into account the FEM model of a V-stack piezoelectric actuator, a filtered PID controller is tuned using the population decline swarm optimizer PDSO algorithm, and gain scheduling (GS) of the controller parameters is used to make the control adapti…
Zero Viscosity Limit for Analytic Solutions of the Primitive Equations
2016
The aim of this paper is to prove that the solutions of the primitive equations converge, in the zero viscosity limit, to the solutions of the hydrostatic Euler equations. We construct the solution of the primitive equations through a matched asymptotic expansion involving the solution of the hydrostatic Euler equation and boundary layer correctors as the first order term, and an error that we show to be \({O(\sqrt{\nu})}\). The main assumption is spatial analyticity of the initial datum.