Edge finite elements are fundamental instruments to solve PDEs resulting from electromagnetic problems: it's now important to define high order families of basis functions whose associated degrees of freedom preserve a physical interpretation. The basis functions of such a family are easy to be defined but they are not linearly independent. This aspect has been taken into account during the implementation: the redundant functions are not eliminated but a new matrix to describe the relations among them is built in order to elegantly incorporate these constraints in the linear system.

Phenomena occurring during early stages of solidification of molten metal into a mould, play an important role concerning the capacity of exchanging heat though the surfaces that are in mutual contact. During the cooling phase, molten metal shrinks, solidify and generates the latent heat according to the solid fraction evolution. The formation of air-gaps leads to a relevant variation in the heat flux, which is controlled for several parameters (i.e. the contact pressure and surface roughness during perfect contact; air-gap dimensions during incomplete contact). Present paper shows an experimental activity aimed at obtaining a relevant air-gap formation during solidification for a sample-casting and at correlating the gap with the exchanged heat. Several thermocouples were used in order to measure the temperature inside the mould and the casting. The exchanged heat was calculated by means of an inverse method and then the Heat Transfer Coefficient, HTC, was calculated. This problem has been examined for the case of aluminium gravity die casting.

The Scilab external module entitled NARVAL enables the performance analysis of algorithms on networks represented by weighted graphs (computer, electric power, road, etc.). NARVAL provides a complete software environment enabling the understanding of available communication algorithms, but also the design of new schemes in order to improve the traffic behaviour of any connection between two network entities. A set of basic functions enables to create network graphs, compute routing algorithms on them and finally make statistical analysis on the data exchange..

In this work, a new finite element framework has been progressively developed in a C++ parallel library in order to simulate the evolution of ductile damage at the microscale. The complex microstructures of the considered metals are modeled using the level set method and are hence immersed in a unique mesh. Coupled with an appropriate anisotropic mesh adaptation strategy, this method enables the simulation of void nucleation, growth and coalescence for various microstructures and loading conditions.

Mechanical and thermal properties of metallic materials are closely related to their microstructures. A better understanding of the mechanisms governing the microstructural evolution during thermo-mechanical solicitations is thus crucial when it comes to optimize the forming processes. Homogenized macroscopic models, also called mean-field models, are widely used in the industry and have a relatively low computational cost. However, given the current metallurgical problems these models might be insufficient. They thus need to be improved and calibrated with more precise simulations. The latter are the so-called full-field models wherein the microstructure and its topology are fully represented. These models enable to simulate the local behavior of the microstructure and predict non-averageable phenomena (such as abnormal grain growth). Recently, a full-field model working in an Eulerian context with level set functions and coupled with Finite Element (FE) computations has been developed and validated at the Centre for Material Forming (CEMEF, Sophia-Antipolis). This method consists in an implicit modeling of the grains constituting the microstructure. This model takes advantage of the efficient tools developed in the laboratory in terms of anisotropic local remeshing and a posteriori error estimation. It has already been used to model the static recrystallization in two and three dimensions with germination and Zener pinning considerations.

Blast furnace represents the dominant hot metal making production process worldwide and one of the main energy consuming processes. Modern research in the field focuses on the increase in plant productivity through energy saving and on the reduction of greenhouse gas emissions compatible with legal limits. Productivity is governed mainly by relevant input parameters such as materials rates, materials properties, and operating conditions. Alt the dominant input parameters and their variations have been analyzed in the present study and they have been optimized in order to increase plant productivity and reduce the greenhouse gas emissions. The raw materials quality analyses was largely taken into account especially with regard to sinter and coke quality. The reducibility of raw materials was demonstrated to largely influence plant efficiency. The modeling of the process was performed on the basis of experimental results, which were collected in a database and processed in modeFRONTIER® in order to obtain metamodels in the form of analytical formula by using the ED algorithm. The study suggests new solutions in all processing parameters in order to improve plant productivity and to reduce the dangerous emissions.

The present study focuses on the numerical simulation of the flow through a bileaflet mechanical heart valve Sorin Bicarbon LFA. A macro scale CFD simulation was performed to assess pressure and velocity fields within the device and to determine shear stress distribution. A transient two-phase simulation was performed to evaluate the time-dependent shear stress acting on platelets through a discrete phase modeling (DPM) approach.

In the design of equipment in pressure, in some cases, is necessary to verify the components resistence against equilibrium instability phenomena ("buckling"): this is necessary when components themselves are loaded by compression forces, due, for example, to external pressure (for vacuum components) and / or to mechanical loads (weight of the structural elements and of the product, wind pressure, seismic action). In many of the above circumstances the components resistance verification is carried out with the use of procedures "by formula", for which there are numerous technical and regulatory references. These procedures, however, are strictly applicable only to simple geometric configurations (cylindrical plating and curved funds), forced with elementary load distributions (uniform external pressure and / or compressive forces evenly distributed). In more complex cases, when the above two conditions are not complied with and, therefore, the adoption of the "by formula" procedures it is not feasible, the use of numerical finite element structural analysis is a useful and objective tool for the execution of the required design checks. For what concerns pressure vessels, the current regulations have implemented, for some years now, the need to use the potential of numerical software by defining specific and detailed criteria for the realization of finite element models and the quantitative interpretation of results.

Native arteriovenous fistula (AVF) is the best vascular access for hemodialysis, but has high early failure rates. Our study was aimed at investigating the effect of flow decrease on flow instability previously found in the juxta-anastomotic vein. We performed an image-based CFD study in a realistic AVF using full (patient-specific) and then halved and quartered flow rates in the proximal artery. The high instability of velocity and wall shear stress has shown a significant damping towards laminar flow. This finding may lead to further understanding of mechanisms responsible for AVF failure.

The aim of this study is to implement computational fluid-Dynamic (CFD) analyses of a prosthetic bileaflet heart valve in a test bench for mitral valve, in order to investigate three different valve conditions. Simulations were supported by experimental analyses. For each configuration a fluid-structure interaction (FSI) simulation was performed, with a physiological transmitral flow curve set as input. Fluid-dynamic fields were evaluated during the entire diastolic period, particulary during the opening phase and the peak instant.

HPDC is a manufacturing process to produce complex metal parts by forcing molten metal into a die. It allows products to be made with high degree of accuracy and repeatability, making it a suitable choice for mass produced product, such as automotive applications. This process usually includes post-casting operations which are actually very important as they determine the final part-quality. This work is focused in the simulation of the post-casting operations for the particular case of an AlSi10MnMg test-part, taking into account the results of the residual stress from the previous HPDC modelling. The developed model shows the methodology integrate solutions of simulations from different specialised software packages and establish communication among them, representing the whole process-chain.

Salento Racing Team is the Formula Student team of University of Salento and takes part to Formula SAE events since 2006. Formula SAE is a student design competition organized by SAE International. Each student team designs, builds and tests a protoype based on a series of rules, whose purpose is both ensuring on-track safety and promoting clever problem solving. CAE software is essential to design a competitive and reliable race car, even more if the time spent on design a new prototype race car is almost one year. The most imperative and largest magnitude of loads transmitted through the chassis frame is torsional load. Torsional stiffness is the resistance of the chassis to torsional loads. These loads are induced by undulating road surface or cornering forces. It is desired that torsional stiffness should be high for a race car design because it permits the handling to be precisely controlled by adjusting the suspension parameters. The chassis is required to be sufficiently stiff to withstand the static and dynamic loads which act during driving conditions. This generally requires a high stiffness to minimize deflection of the chassis and hence the movement of all the mounting points for power train and suspension components. The most common measure for chassis stiffness is torsional stiffness. This assumes that if the car is sufficiently stiff under torsional loading, then it will normally withstand bending and longitudinal/lateral bending.

This poster focuses the attention on the flexibility of CFD softwares, in particular it is underlined the use of simulation, both in the earlier stage of design and in the later stage of optimization,to better choose the geometry of the components of a Formula Sae car. In this work were analyzed, particularly, components relating to the aerodynamics and to the variable intake system.

The project focuses on the physical modelling for packaging systems, developing and assessing suitable mathematical and numerical models for the simulation of FSI problems. In order to assess the integration between physical models (e.g. the multiscale FSI models) and the control logic operating on the real packaging system, a first reduced model has been identified, still maintaining the hybrid nature of the control problem.We present the results obtained for two reduced systems (dampeners: flange and bucket) detailing the differences in terms of model definitions and numerical results.

The power required to fly a rotorcraft, and consequently the fuel burn and CO2 emissions are strongly dependent on the design of its airframe and of non-lifting rotating parts such as the main and tail rotor shaft, control system and hub. In line with the EU environmental objectives for 2020 the Clean Sky Green Rotorcraft Programme aims at reducing CO2 emission by 26-40% and NOx emission by 53-65% per mission. The University of Padova in collaboration with Hit09 S.r.l. has taken part in the Clean Sky activities in four different projects: HEAVYcOPTer, TILTOp, CODE-Tilt, DREAM-Tilt. All these projects have a common objective: redesign of rotorcraft components in order to minimize aerodynamic drag; up to 8% overall drag reduction is shown feasible.The methodology adopted to achieve this goal is CFD optimization employing an innovative multi-objective evolutionary algorithm; starting from a baseline configuration, the optimizer performs a perturbation of the original geometry and a CFD simulation is run in order to evaluate the performance of the new component shape. By this way, after a suitable number of iterations, the algorithm is able to propose different Pareto-optimal configurations which can be chosen by the designer. The first three projects all employ the same optimization methodology. HEAVYcOPTer deals with the optimization of the engine installation of the AW101 helicopter; TILTOp is focused on the redesign of the engine intake and exhaust of the ERICA tilt-rotor; CODE-Tilt is aimed at drag reduction of various aerodynamic surfaces (nose, empennages, wing-fuselage junctions, etc.). DREAM-Tilt, instead, is proposed with the objective to assess the aerodynamic performance of the new design solutions by means of wing tunnel tests.

Mitral regurgitation, mainly induced by degenerative mitral valve prolapse, has been increasingly treated through percutaneous MitraClip® implantation. The present study aims to evaluate quantitatively and qualitatively the hemodynamic before and after device placement. Two valve configurations were inserted in left heart domain. The comparison was performed by velocity, transvalvular pressure drop and orifice area indices. Results showed an overall worsening in open-valve hemodynamics after mitral valve repair.

Peridynamics is a new non-local continuum theory well suited to model crack propagation. The presence of cracks in a solid represents a discontinuity in the displacement field and the peridynamic formulation, which uses only integrals, overcomes the problems of the classical continuum theory of solid mechanics, based on spatial derivatives of the displacement field itself. The purpose of this research is the implementation of the peridynamic approach in a commercial FEM software. The validation is obtained conducting both dynamic and static simulations.

This paper deals with interleaving a nanofibrous mat between laminate plies to control the interlaminar delamination strength. In previous works, the authors tested delamination toughness and identified the cohesive zone properties of nanomats with varying fiber diameter, fiber arrangement (random, aligned), mat thickness. The results showed that, by varying those parameters, a toughening or an embrittlement of the interface can be obtained. The modification induced by the nanomat can be therefore exploited in order to tailor the interply delamination strength of the laminate. The aim of this work is to simulate the impact strength of a composite laminate with nanomodified interplies of different strength in order to maximize the impact energy absorbed by the composite, in the perspective of optimization for use in impact attenuation.

Finite element analysis was used to quantitatively compare, on a patient-specific basis, the biomechanical effects of a broad spectrum of different neochordal implantation techniques for the repair of mitral posterior leaflet prolapse. Systematic biomechanical differences between neochordal techniques were noticed with multiple neochordae configurations better redistributing mechanical stresses on the leaflet. The performed tests may potentially impact the clinical outcome of the procedure and promote a patient-specific optimization of neochordal techniques.

Hierarchical model reduction is a novel technique to effectively solve problems of incompressible fluid dynamics in pipes and networks. It consists of coupling finite elements along the axial direction with spectral methods for the transverse ones. This allows to assemble "psychologically 1D" network models still with the possibility of adaptively refine the local accuracy. This approach can be coupled with Proper Orthogonal Decomposition techniques to effectively perform parameter estimation (HiPOD). The reference application is cardiovascular mathematics.

There is an increasing number of wireless applications where the transmitting and receiving antennas are very close to each other (each antenna is in the near-field region of the other). Among them, it is worth mentioning the RFID systems for item level applications, intra-body and on-body communications, near-field focusing in RF hyperthermia and microwave imaging, short-range communications, wireless power transfer. In this context, conventional far-field parameters and simple link-budget formulas are inadequate, and accurate numerical models and effective simulation tools become essential.

This work aims to find the possible correlations between process parameters and castings quality, defined by means of visual inspection analysis and porosity content investigation. The link between input parameters – the process ones – and the outputs, which are the castings quality levels, are provided by temperature, pressure, plunger displacement and velocity sensors. The experimental procedure followed generates an amount of data that can be related to each other through graphic correlations in order to understand how the quality of the castings is influenced by the process parameters.

The stress variations induced by gas/oil production or injection may activate pre-existing regional faults. In order to predict the possible consequences on induced/triggered seismicity, it is of paramount importance to simulate the fault mechanics in an accurate and realistic way. Faults yield discontinuity in the displacement field. Classic finite elements (FE) can represent only continuous displacement fields. Interface finite elements (IE) are introduced to simulate faults. Two principal methods exist to enforce contact condition on interface elements: Penalty and Lagrangian. The present study proves that the Lagrangian approach is more robust than the Penalty one, thus offering more regular solutions. Furthermore, the use of a Newton-Raphson scheme to treat the non-linearity allows a quadratic convergence.

During the evaluation of stenting techniques for the treatment of coronary bifurcations, virtual modeling based on numerical methods is emerging as a valuable tool for the assessment of several biomechanical variables (e.g. stent strut stresses, shear stresses) that are hardly detectable with in vitro or in vivo experiments. In this study a numerical framework that includes structural, fluid dynamics and drug-eluting numerical models was implemented. In particular, the double-stenting culotte technique was investigated by comparing the behavior of conventional and dedicated stents.

We present a novel technique for assembling low mass drift chamber. It was developed to meet the stringent requirements imposed by the experiments that require momentum resolution of order 100-200 keV/c for cherged particles in the momentum range 50 to 100MeV/c. Examples of such experiments include MEG at PSI and Mu2e at Farmilab, both of which will have a momentum resolution that is limited by the multiple scattering contribution.

Three examples of response prediction of structural walls by means of static and dynamic analyses are reported. Non linear finite analyses have been carried out with Abaqus code by adopting multi-layered shell elements. The non linear behaviour of RC walls is evaluated with PARC_CL crack model implemented in the user subroutine UMAT.for for loading-unloading and reloading conditions. The presented procedure let to evaluate the resistance of slender or squat walls subjected to in-plane and out of plane actions, the interaction between actions for every transversal cross section shape.

The aim of this work was the design optimization, by means of 3D CFD simulations, of a novel receiving cavity for Concentrated Solar Power applications. The receiving cavity, made of a helically coiled steel tube, is highly effective in converting the radiative energy coming from the sun into thermal energy gathered by air which was selected as heat transfer fluid. The geometrical parameters considered for the optimization were: cavity height, varied by increasing or decreasing the number of coils, cavity external diameter, and the presence of a spiral coiled tube closing the cavity top.

Transplantation is the gold standard to treat cardiovascular pathologies; however, limited availability of fresh organs automatically requires the adoption of Ventricular Assist Devices (VADs). This work presents an innovative CAE approach for analyzing the fluid dynamics of a pediatric pneumatic device. In order to realistically mimic the membrane kinematics and quantitatively capture the hemodynamics inside the device, a dynamic mesh boundary technique was adopted. Computational results well compare with Particle Image Velocimetry (PIV) data.

Aseptic filling technology of Spouted Pouch packaging, increasingly used in the beverages sector, requires a very complex sterilization and rinsing of the packaging before filling. This work deals with the sterilization process of a pouch packaging used in aseptic technology. A mixture composed by vaporized hydrogen peroxide and hot sterile air is used as sterilizing agent and it is injected into the package through a sterilization nozzle. A CFD multicomponent model in ANSYS CFX (version 14.5) has been created and validated in order to simulate the real process. Given this model, this paper aims to minimize the H2O2 consumption and to maximise the sterilization treatment of the packaging. This issue has been approached using a multi-objective optimisation software aging on CFD multicomponent simulations. The best position of the nozzle inside the pouch and the optimal treatment time, concentration and flow rate of the sterilizing mixture have been obtained as the main results of this work.

In the present work we explore the idea of using a fully actuated design for an unmanned aerial vehicle developed for aerial manipulation. To this aim, a Trirotor equipped with a prismatic arm has been adopted. An accurate analysis of the mechanical design and modeling of the vehicle has been performed. Particular attention has been given to the analysis of the destabilization effects caused by the arm motion, during the vehicle flight. A system control, able to stabilize the vehicle in different flight conditions, has been developed and implemented in two different simulation platform, for verification and validation purposes. The results show that the fully actuated design is effectively able to improve the performance of aerial manipulation devices. The proposed approach provides useful insight into both aerial manipulation and UAV fields, suggesting that the number of potential applications of this vehicles will likely grow in the next future.

Experimental set-ups are adopted to obtain an overall quantification of the performances of artificial heart valves. This work presents an innovative computational tool that mimics realistic operative conditions of a testing benchmark adding localized and more precise information. A micro-scale analysis was accomplished, via a particle tracking methodology, to identify thrombogenic hot spots allowing for further possible design modifications to minimize the blood damages. Results showed a confident replica of the experimental conditions and an in depth prevision of high-risk design locations.

As a standard test-bar permanent mould, the "Stahl" Mould has been widely used in foundries to assess the properties of aluminium cast alloys. However, lower mechanical properties are often obtained with this mould due to filling turbulence and shrinkage-induced microporosity in the gauge section. In order to improve the mechanical properties, a new design of test-bar permanent mould was evaluated and studied in this work by computer aided simulation. Numerical simulations have been performed to study the filling and solidification behaviour of an A356 alloy, in order to predict the turbulence of the melt and the microshrinkage formation. Different process parameters, such as the temperature of the bath and the die, the use of a foam filter were systematically varied and analysed in the design of experimental matrix.

The fluidity of an alloy in the liquid state influences the foundry molds' dynamic filling. In this work a real fluidity test, that is based on Archimedean spiral's principle and it has been carried out on an A356 alloy, has been numerically simulated. The cavity reproducing spiral geometry is formed in sand mold. The liquid metal, which is poured into the cavity, goes across a stretch of the spiral before solidifying, and the length travelled gives an assessment of the metal fluidity. The real fluidity test helped to calibrate a numerical simulation software, with the aim to identify the correct boundary conditions necessary to simulate both the real behavior of the metal and the metal-mold interactions.

Permanent Magnet Heaters, PMH, have been recently proposed as a possible high efficiency solution for the heating of high conductive metals. The optimal design of a Permanent Magnet Heater is presented with reference to a real industrial case. The design has been carried out by means of transient magnetic and thermal 2D and 3D Finite Element Models coupled with multiobjective optimization algorithms.

A mixed functional representation, based on the Finite Element Method and the Meshless Local Petrov-Galerkin (MLPG) method, is presented in Structural Mechanics. MLPG nodes do not need any underlying topology, and they can be easily added and moved in the computational domain. Thus, there is no need to remesh in a refinement process, only the MLPG particles are added in the area of interest. Numerical experiments are presented in order to assess the quality of the enriched solution.

The poster shows the optimization of the aeropack of a formula SAE car performed with a CFD simulation software using geometries generated with an indipendent CAD software or the integrated geometry instruments. The study starts with the choice of the downforce to generate to have the best performance in handling, it continues with the choice of the airfoil the design of the rear wing, the simulation of the entire car to study the integration of the wings with the mainframe of the car. then the real downforce values are evaluated with a real test on track.

OBJECTIVE: development of an aerodynamic package for a Formula SAE car. STEP OF THE SIMULATION PROCESS: Import: the wing's geometry was designed by CAD and imported in Ansys Workbench CFD: a 3D solver for K-ε RNG model was used to create a pressure map around the wing at the top speed of the vehicle CFRP simulation: the ACP module was used to reproduce the carbon fibre behaviour, all elements were suitably oriented according to the orthotropic properties Structural analysis: the static structural analysis allowed to find out the stress distribution in the component with the actual boundary conditions. TARGET: reduced wing deformation, simple manufacturing process, low production costs

The Titanium high strength-to-mass ratio Ti-6Al-4V alloy is one of the key materials in advanced engineering applications, especially when high resistance is required for critical, low-weight components. Based on a linear, plane stress, elastic FE model of a cracked smooth flat dogbone specimen, propagation models have been implemented to predict the crack propagation rates for smooth specimens, by using Paris, Walker and Kato-Deng-Inoue-Takatsu propagation formulae.
The different outcomes from the forecasting numerical models were compared with experimental results, proposing modeling procedures for the numerical simulation of fatigue behavior of a Ti-6Al-4V alloy.