In this study, an innovative mesh generation approach for the structural analysis of historical monumental buildings is presented. The method consists in a peculiar breakdown of the geometry starting from laser scanner or photogrammetric surveys. A large reduction in the required time in comparison to CAD-based modeling procedures is achieved. A geometrical and structural validation of the method is carried out on a historical masonry castle application. The findings show good reliability and effectiveness of the FE model generation approach.
Looking at the evolving technology trends in CFD-based shape optimization, there is a strong request for Adjoint Optimization based solutions. In external aerodynamics the most convenient approach relies on the use of aerodynamics indices as targets. The desired effect is to improve aerodynamic efficiency using the outcomes of an Adjoint CFD RANS simulation to drive the CAD morphing. For these reasons an Adjoint Solver for turbulent external aerodynamics problems has been developed in the open-source CFD Toolbox (OpenFOAM) . The application presented shows how a more than 5% drag reduction can be obtained in a single shot adjoint-driven shape optimization for an automotive CAD definition.
The aim of the work is to study the influence of the saccadic movements and the physiological boundary conditions on the drug distribution inside the vitreous humour in patients affected by AMD and treated with an injection of anti-VEGF. This study shows that the saccadic movements cannot be neglected due to their great influence on both the fluid dynamic and the drug delivery mechanism. A complete characterization of the surrounding tissues is also mandatory in order to consider the changes in permeation across the RCS complex and the specific anti-VEGF consumption nearby the retinal surface.
In the framework of my PhD research activity, several novel design solutions for high performance cooling systems have been analyzed and developed, permitting to evaluate the challenging heat transfer conditions foreseen in the future fusion devices.
The project, called Multi-design Innovative Cooling Research & Optimization (MICRO), aims, on one hand, to verify the present solution applied inside the accelerating grids in MITICA experiment (the 1MV Neutral Beam Injector currently under construction in Padova) and, on the other, to perform further improvements in the heat transfer process with an acceptable pressure drop and reliable manufacturing process. The grids of the MITICA accelerator, whose function is to accelerate a beam of negative hydrogen ions by means of electrostatic potentials, are in fact subjected to extremely high heat loads, concentrated around the apertures for the ions. Some of these grids are particularly critical by the thermo-mechanical point of view, because they are exposed both to the beam halo and to a large amount of electrons generated by stripping reactions inside the accelerator. The consequent heat load has typically an annular distribution around the apertures with peaks of 10 MW/m2 and around 1.4 kW to be evacuated per aperture, causing a high cooling complexity. A comprehensive parametric investigation has been then carried out with the goal of defining a novel set of cooling proposals whose aim is to lower the temperature gradients inside the copper grid to the maximum reasonable extent, while respecting the set of constraints given by this particular application. The main advantages rely in the decrease of the associated strain and stress field inside the grids, obtaining the possibility to extend the fatigue life-cycle of these components characterized by high thermal stress and to investigate the possibility to employ alternative dielectric fluids instead of water. Such design solutions would in fact allow the exploitation of less performing fluids in terms of cooling capability. Despite the unavoidable deterioration of the cooling performances such approach would represent a significantly advantageous option with respect to the existing ultra-pure water technologies. This is particularly relevant in view of DEMO and future power plants characterized by higher efficiency and reliability. Due to the objective difficulties in reproducing the reference thermal load given by the Neutral Beam Injector optic, the innovative solutions will be tested in a domestic experimental tests facility (ICE - Insulation and Cooling Experiment) where the applied heat flux will be given by the exploitation of ceramic heaters. The poster gives an overview of the performed activities, starting from the introduction of the problem, to the CAE campaign, till the manufacturing of the prototypes.
The activity was originated in the framework of a collaboration between University of Pisa and Global Garden Products (GGP). The goal was to develop multilevel simulation and experimental tools aimed at characterizing the vibration behavior of a Lawn Tractor. These tools can be used to improve the comfort of the driver of the tractor and to avoid components resonance due to engine and blades excitations. A Semi-flexible MultiBody model and a Finite Element model were developed and successfully validated through comparison with experimental results.
In the present work, in order to evaluate the deformation behaviour of a titanium alloy under superplastic conditions, an experimental-numerical approach was used. In particular, starting from Free Inflation Tests with a constant pressure profile and a pressure profile based on jumps between two different values, the strain rate sensitivity index (m) value was obtained by means of the inverse analysis based on a genetic algorithm. The subsequent comparison between the results of the numerical simulations implementing the data obtained from the inverse analysis and the experimental results show a good agreement.
The presented approach focuses on optimization solutions for the design and management of production networks for the manufacturing and final delivery of innovative products and services. Decision support tools for long-term to short-term planning tasks in the production network are developed and applied in the aeronautics industry and the home appliances industry within the scope of the ProRegio project.
In this study, an innovative mesh generation approach for the structural analysis of historical monumental buildings is presented. The method consists in a peculiar breakdown of the geometry starting from laser scanner or photogrammetric surveys. A large reduction in the required time in comparison to CAD-based modeling procedures is achieved. A geometrical and structural validation of the method is carried out on a historical masonry castle application. The findings show good reliability and effectiveness of the FE model generation approach.
Sintering is a process for ironmaking operations; it represents one of the main sources of production emissions of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzo-furans, NOx and SOx. In the present study, the operating conditions through which a reduction of dangerous emissions can be achieved are defined through numerical analysis. By employing a multiobjective optimisation tool, a deep analysis capable of representing the process behaviour leading to the optimal operating conditions was developed. Through such analysis, a broad range of processing parameters affecting the development of PCDD/Fs in the sintering process has been evaluated. The first aim was the possible reduction of dangerous emissions through numerical and experimental analyses allowing the definition of the optimal conditions for the minimisation of pollutants. Although the resultant optimal combination of input parameters able to reduce the dangerous emissions from the plant was determined, it was largely examined on the impact of the chosen input parameters on the sinter productivity. In such a way, it was possible to reduce the emissions close to the legal limits and with a high level of productivity and efficiency of the plant. Using the optimisation software modeFRONTIER (ESTECO), a virtual surface that can reproduce the actual process of sintering was created.
In HPDC, defects can seriously damage the in-service performance of aluminum alloy products. The influence of defects on the mechanical properties of a high-pressure die cast component is reported. Its behavior was studied by means of a FE simulation model. The X-Rays were used to detect porosities and static tests were performed to determine mechanical behavior. SEM and image analysis techniques were used to quantitatively assess porosity and oxide distributions on the fracture surfaces of the components. A damage criterion was formulated to consider the influence of defect position and orientation on the component lifetime.
The PVD (Physical Vapor Deposition) coating is one of the surface processes used to improve mechanical properties in engineering applications. Based on a linear, plane strain, elastic FE model of high performance spur gears, residual stresses produced by WC/C coating and pressure between the flanks of teeth during the contact have been simulated. Therefore a propagation model has been implemented to predict the crack propagation for the coated elements, comparing stress the intensity factor range with the threshold stress intensity factor, defined by using the theoretical models of El-Haddad, Murakami-Endo and LEFM (Baragetti S., Int. J. Fatigue, 2007). The outcomes for the coated spur gears were compared with the uncoated ones to underline effective increments in fatigue resistance.
Recent high-end processor architectures offer advanced power-monitoring and power-saving features. In this work we exploit these features, in order to tune the computing energy consumption. We present simple techniques to tune processors clock frequencies (for both CPUs and GPUs) on a per-function and per-application basis, measuring the effects of these optimizations in terms of the consumed energy and execution time. As a test case we adopt a Lattice Boltzmann fluidodynamics simulation, showing a 7% energy saving, while running on a 16 GPUs computing node, without any performance degradation.
Mechanisms of side branch (SB) compromise after stenting of coronary bifurcations are poorly understood. The impact of bifurcation angle and plaque composition was investigated by means of numerical simulations of stent deployment. Main vessel stenting caused an ovalization of the SB ostium (i.e. SB entrance) that might appear as a significant stenosis in 2D angiography, although the SB ostium area is preserved in absence of calcifications. Plaque type affects the shape of SB ostium while bifurcation angle has minimal impact. SB compromise is severe only in cases with calcifications.
The purpose of the present work is to develop a 1D simulation method for a thermal Active Clearance Control (ACC) system. This device, employed into modern aircraft low pressure turbines, improves the engine efficiency.
This approach couples the fluid-dynamics and the thermal aspects, having lower requirements in terms of computational time and costs than a 3D CFD simulation. The first one simulates the ACC 1D fluid-dynamics, evaluating the overall mass flow and the pressure losses. The second one is an analytical tool performing the ACC heat pick-up analysis.
Looking at the evolving technology trends in CFD-based shape optimization, there is a strong request for Adjoint Optimization based solutions. In external aerodynamics the most convenient approach relies on the use of aerodynamics indices as targets. The desired effect is to improve aerodynamic efficiency using the outcomes of an Adjoint CFD RANS simulation to drive the CAD morphing. For these reasons an Adjoint Solver for turbulent external aerodynamics problems has been developed in the open-source CFD Toolbox (OpenFOAM) . The application presented shows how a more than 5% drag reduction can be obtained in a single shot adjoint-driven shape optimization for an automotive CAD definition.
The commercial software Ansys Fluent was used to conduct an incompressible and isothermal RANS study about a turbulent cavitating flow over a cylindrical body under supercritical conditions. A unique velocity field was computed through a homogeneous equilibrium modelling approach and the use of the k-w SST turbulence model. The turbulent viscosity was modified to take into account of the presence of two phases, the liquid water and the water vapour. The 3D results yielded a correlation between the Strouhal and the cavitation number showing a great correspondence with experimental observations.
Percutaneous intervention through stent deployment of the Left Main coronary bifurcation has difficult clinical aspects. Currently, new stenting techniques are under investigation. In this study, numerical simulations are performed to compare the biomechanical outcomes of a standard technique (i.e. simultaneous kissing stenting) with a new one. A sequential strategy is implemented. In particular, the deformed geometry of the artery, obtained from structural analysis of stent deployment, is used to extract the fluid domain for subsequent fluid dynamics simulations.
Coronary artery disease is one of the leading causes of death in the world. For high-risk patients, coronary artery bypass graft is the preferred treatment. However, despite excellent patency rates, bypasses may fail due to restenosis. In this context, we present a computational study of the fluid-dynamics in patient-specific geometries with the aim of investigating a possible relationship between coronary stenosis and graft failure. We also propose a strategy to prescribe realistic boundary conditions in the absence of measured data, based on an extension of the well-known Murray's law
The aim of the work is to study the influence of the saccadic movements and the physiological boundary conditions on the drug distribution inside the vitreous humour in patients affected by AMD and treated with an injection of anti-VEGF. This study shows that the saccadic movements cannot be neglected due to their great influence on both the fluid dynamic and the drug delivery mechanism. A complete characterization of the surrounding tissues is also mandatory in order to consider the changes in permeation across the RCS complex and the specific anti-VEGF consumption nearby the retinal surface.
The creation of meshes for 3D printed structures is a complex aspect in the design process which must be addressed if a FEM analysis is required. In the following method enabling an automated tool for the fast mesh generation of 3D printed structures is explained.
A solution that can integrate all aspects (social, economic, environmental) in a single operation. This means that there is a minor waste of resources, and therefore economical using Upcycle materials. The proposed solution aims to be food for thought and a model for future interventions, as the theme of building design needs solutions that respect the environment. One of the aspects in the modeling of a tall building requires to take into account the optimization in the choice of profiles. In the model is used an iterative method to assign the appropriate profile to each member.
Research activities are about a project aimed at analysing aeronautical composite-made structures, characterized by defects or damage. Two different approaches are exploited: an analytical method, providing stress-prediction at interface of a stiffened structure that may describe an incipient delamination/debonding, and a numerical method, providing residual strain and fracture strength of a stiffened structure with a de-bond defect.Analytical model has been implemented in Scilab software, numerical model developed in Ansys software.
The function of diseased native heart valves can be replicated by heart valve prostheses. The potential of Polymeric Heart Valves (PHVs) is to combine the hemodynamic propertied of biological valves with the durability of mechanical valves. The aim of this work is the verification of advantages of Fluid-Structure Interaction (FSI) simulations, compared to structural analysis, to capture real kinematics of a new PHV. Application of the FSI methodology to a patient-specific case is also outlined.
Selective catalytic reduction with urea is one of the most important industrial applications involved in NOx emissions reduction in power plants. The optimization of such systems is complex and can take advantage using automatic open-source tools and HPC platforms. An automatic optimization workflow has been developed for this applications using open-source tools. The workflow is meant to autonomously evolve from a baseline plant CAD design to an improved one modifying the angle of the turning vanes. The New Design obtained shows an improved value of the target RSD index of more than 7%.
In the poster the new PARC_CL 2.0 crack model (Physical Approach for Reinforced Concrete under Cyclic Loading condition) is presented. The PARC_CL 2.0 crack model, implemented in the user subroutine UMAT.for in ABAQUS code, is based on a fixed crack approach and allows to consider plastic deformations and hysteretic cycles. In the poster, the PARC_CL 2.0 crack model is firstly illustrated, highlighting the cyclic behaviour of concrete and reinforcement. Successively the model is validated by means of comparison with experimental tests on simple RC panels and finally the model is applied on the assessment of the cyclic behaviour of RC shear walls.
The poster presents a simulation-based study of a Flexible Manufacturing System (FMS). The evaluation, performed by means of a discret-event simulation model, considers Industry 4.0 concepts for supporting the integration of innovative technologies. The poster shows the necessary steps in order to build the printer, to define its settings and to develop the simulation model. The objective was to verify if simulation can faithfully reproduce the 3D-printing process and hence demonstrate the suitability of involved technologies for the application in industrial scale.
Flow-focusing is technique aimed to align particles suspended in fluids flowing in microfluidic devices, and is required in a variety of applications, e.g., counting, detection and separation. In this contribution, we show, by means of extensive 3D finite element simulations, that fluid viscoelasticity strongly enhances the flow-focusing mechanism allowing to align particles in few centimeters of a straight microchannel. The focusing mechanism is deeply investigated by varying the geometrical, flow and rheological parameters. A viscoelasticity-based micro-focuser is designed and optimized.
Terrorists have proven that they might be able to circumvent security scans both by carrying explosive devices onboard themselves and by sending parcel bombs via mail or hidden in luggage. Currently security scans are necessary, but cannot guarantee a 100% detection rate: complementary passive countermeasures are needed in order to protect aircrafts, crew and passengers in case an explosive device is smuggled onboard. The threat of attacks to passenger airplanes with explosives hidden in luggage loaded in the cargo holds or taken onboard is dramatically evident from terrorist events in the past years. FLY-BAG2 goal is to develop innovative solutions based on novel lightweight materials and structural concepts for the mitigation of the effects of an on-board blast improving aircraft survivability. Direct strengthening of the airplane structure is not a viable solution since it would clearly result in thicker skins and a weigh penalty; moreover, the related costs could not be justified in the majority of the commercial routes. Instead, the proposed blast mitigation and retrofitting solutions have been developed to be easily implemented on existing aircrafts
In this poster Computational Fluid Dynamics (CFD) and Finite Elements Analysis (FEA) are applied to the field of fire safety engineering. For ventilation analysis in large spaces, like tunnels, CFD is employed to simulate the flow field both with and without fire. FEA coupled with CFD are employed to simulate the response of concrete structures exposed to fire. CFD allows to calculate boundary conditions for the structural analysis which are directly related to the specific fire scenario, while FEA allows to evaluate the response of the structure.
The efficient analysis of CAE models requires well-optimised parallel computing codes that extract the best performance from hardware. The Performance Optimisation and Productivity Centre of Excellence in Computing Applications (POP) is funded by the European Union to boost the productivity of European academia and industry by discovering inefficiencies in existing applications and suggesting improvements. Its services are delivered free of charge to organisations based within the EU. This poster will highlight the benefits that POP's users have realised through a number of case studies.
The research presented in this poster was carried out under the activity 5.2 of SPIA project – Strutture Portanti Innovative Aeronautiche , or, in English, Aeronautical Innovative Bearing Structures- (funded by the Italian government grant : Pon 2007-2013 “Ricerca e competitività” PON03PE_000067_3). This activity pursued an improvement of manufacturing data distribution and the analysis of related issues by introducing engine parts tracking via RFID tags. The project has been developed in collaboration with Avio Aero Brindisi Plant where MRO activities are performed on aircraft engines and with Enginesoft. The main issue of this environment is the massive presence of metallic components which may interfere with electromagnetic fields of real time positioning technologies. The poster illustrates the main milestones of the project and the needed electromagnetic simulation of a sample environment.
The performance of the composite materials are strongly influenced by the production processes. In particular, for thermosetting resins, there are many factors causing residual stresses and distortions. These lead to higher cost and lower component performance. The poster presents two studies, which try to address the problems. The former study deals with the development of a numerical procedure for thermal analysis and its calibration using experimental data; the latter illustrates a thermo-structural procedure used to compare stringer’s performance with and without the cure effect.
The impressive chain of disastrous earthquakes occurred worldwide during last years revealed an increasing need of a resilient and safe society and of a reliable seismic risk evaluation, with trustable assessment of earthquake-induced damage and loss. Nowadays, 3D models allow us to reproduce the most significant features of strong ground motion, as: (i) different seismic source scenarios; (ii) propagation path in heterogeneous media; (iii) complex tectonic and geological structures; (iv) variability of strong ground motion.
In this work we study the multi-scale wave propagation problem occurerd during the 22 February 2011 Mw 6.2 Christchurch earthquake. The problem is fully assessed from the regional scale of the Canterbury Plains to the urban scale of the Christchurch Central Business District (CBD). This application, made possible by the performance features of the numerica code SPEED (https://speed.mox.polimi.it), represents a step further in promoting a novel “from-the-seismic-source-to-the-structure” multi-scale computing approach for seismic risk assessment.
Optimization process plays a central role in industrial design, even more in automotive. In the present study we applied ANSA® morphing and optimization tools to improve HVAC system efficiency, aiming to set up a methodology to reduce the duct total-pressure drop. The starting geometry is modified in a random optimization process. Many new configurations, meeting space requirements with improved performances, are identified. The procedure developed is suitable for aerodynamics optimization, not only for automotive, but also for other range of applications.
Gas-liquid bubble columns are widely used multiphase reactors where extremely complex fluid dynamics interactions between the phases exist. We have studied, experimentally and numerically, a large-scale bubble column. In particular, we have coupled different experimental techniques to provide a comprehensive view of the bubble column fluid dynamics, considering both the bubble and the reactor scales. In the numerical part, a CFD model is proposed, validated against the experimental data and compared with the performance of the state-of-the-art baseline model developed at the HZDR.
The performance of the Large Hadron Collider (LHC) strongly depends on the correct functionality of the collimation system. The robustness of collimators in beam accident scenarios is very relevant for the LHC operation and its risk optimisation. A numerical Finite Element (FE) model is developed and applied to investigate the thermo-mechanical response of a tertiary collimator in novel jaw error cases. The developed FE model is complemented by material characterisation tests as well as by a dedicated beam experiment that has successfully validated the reliability of the developed FE model
Rheologic created a novel solver implementing phase transitions in the gas-phase and on surfaces including condensation, evaporation and (re)sublimation for arbitrary pure substances for use within OpenFOAM® called mollierSolver. Conjugate heat transfer, radiation and compressible, turbulent flow are included in the solver. The solver's performance was successfully validated against an experiment. Future work will include modeling of morphological surface-effects and simulations and assessments of urban microclimate.
Polymeric Heart Valve (PHV) prostheses aim at combining the hemodynamic advantages of biological valves with the durability of mechanical valves. Styrene Block Polymers (SBPs) appear as the best materials to this purpose, due to their good biocompatibility, chemical stability and fatigue resistance. Moreover, these materials can be processed by injection moulding allowing the alignment of the polystyrene micro chains. The aim of this work is the investigation of the micro chains orientation within the PHV leaflets produced by injection moulding in order to optimise the PHVs manufacturing.
The presented work deals with the shape optimization of a high speed flywheel. An evolutive system algorithm is presented, in order to allow a multi-parameter description of the flywheel's 2D profile. A parallelization strategy is proposed to deal with the high number of simulations to perform. Using the algorithm, a family of flywheels is generated in order to assess the influence of the design parameters on the optimal shape. The method is used to obtain an optimized solution for an asymmetrical shape, where a mechanical interface is attached on one side only.
In this work we employed a Collocation Meshless Method based on Radial Basis Functions (RBF) to numerically solve a 2D Poisson equation (steady state heat conduction problem). We focus our attention on an automatic point generation procedure based on quadtree technique coupled to a refinement procedure to generate point distributions on practical geometries with enough point spacing quality to produce results as good as those obtained with specific high quality point distributions, available only for simple geometries.
A novel approach to modelling and simulation of the industrial compaction process of ceramic powders is proposed, based on a combination of: continuum mechanics modelling of the constitutive response of the material; finite element discretization and computer implementation of the mechanical model; parametric identification by a multi-objective optimization of simulated experimental tests. The capabilities of the proposed approach are highlighted through computer simulations of realistic industrial compaction processes, namely, the forming of axisymmetric tablets and of three-dimensional ceramic tiles.
In the galvanizing process, the jet cooler is a device that provides a rapid cooling of a moving metal strip. The aim of this work was to develop a CFD model to check the performance of a galvanizing cooling line based on jet impingement. Validations have been done for the CFD model studying the single-jet and the multi-jet cases. Detailed experimental data from open literature have been used to set up and to validate the CFD approach. The work was developed in cooperation with Danieli Centro Combustion and the DIME Department in the University of Genova.
Nitinol (NiTi) peripheral stents are used for the treatment of superficial femoral artery (SFA) diseases. SFA is subjected to cyclic loads and an implanted stent can incur on long-term fatigue failure. Computational FE models are a useful tool in taking into account in-vivo conditions and analyze stent behavior. Accurate descriptions of the device geometry and material properties are mandatory. In this study, an effective and validated experimental-numerical approach is developed and applied to possible applications in the research field and in clinical in-vivo patient-specific case.
A fire engineering strategy defines the fire safety objectives and performance requirements and all methods by which provide to ensure safety and protection. In recent years, there has been an increase in use of Fire Dynamics Simulator (FDS) for performance-based analysis in the area of structural fire research. The aim of this research activity is to contribute to make stable and reliable coupling system between FDS and FEM codes through validation tests of increasingly complex geometries with the objective to apply this technique to all connected application fields.
This poster proposes an experimental software to review CAD models and CAE simulations results allowing collaboration within geographically distributed teams. Engineers of such teams can create a review session where each participant can have a synchronous or asynchronous view of the CAE simulation, thus consenting him to focus on a particular feature of the results. The experiment uses an active replication approach in order to reduce the required network bandwidth. In addition it supports stereoscopic visualization and provides tools for interacting with the loaded results and for improving communication among participants. Users evaluations show that the use of a collaborative virtual environment with special tools may enhance the cooperation among CAE engineers during the review process.
In the framework of my PhD research activity, several novel design solutions for high performance cooling systems have been analyzed and developed, permitting to evaluate the challenging heat transfer conditions foreseen in the future fusion devices.
The project, called Multi-design Innovative Cooling Research & Optimization (MICRO), aims, on one hand, to verify the present solution applied inside the accelerating grids in MITICA experiment (the 1MV Neutral Beam Injector currently under construction in Padova) and, on the other, to perform further improvements in the heat transfer process with an acceptable pressure drop and reliable manufacturing process. The grids of the MITICA accelerator, whose function is to accelerate a beam of negative hydrogen ions by means of electrostatic potentials, are in fact subjected to extremely high heat loads, concentrated around the apertures for the ions. Some of these grids are particularly critical by the thermo-mechanical point of view, because they are exposed both to the beam halo and to a large amount of electrons generated by stripping reactions inside the accelerator. The consequent heat load has typically an annular distribution around the apertures with peaks of 10 MW/m2 and around 1.4 kW to be evacuated per aperture, causing a high cooling complexity. A comprehensive parametric investigation has been then carried out with the goal of defining a novel set of cooling proposals whose aim is to lower the temperature gradients inside the copper grid to the maximum reasonable extent, while respecting the set of constraints given by this particular application. The main advantages rely in the decrease of the associated strain and stress field inside the grids, obtaining the possibility to extend the fatigue life-cycle of these components characterized by high thermal stress and to investigate the possibility to employ alternative dielectric fluids instead of water. Such design solutions would in fact allow the exploitation of less performing fluids in terms of cooling capability. Despite the unavoidable deterioration of the cooling performances such approach would represent a significantly advantageous option with respect to the existing ultra-pure water technologies. This is particularly relevant in view of DEMO and future power plants characterized by higher efficiency and reliability. Due to the objective difficulties in reproducing the reference thermal load given by the Neutral Beam Injector optic, the innovative solutions will be tested in a domestic experimental tests facility (ICE - Insulation and Cooling Experiment) where the applied heat flux will be given by the exploitation of ceramic heaters. The poster gives an overview of the performed activities, starting from the introduction of the problem, to the CAE campaign, till the manufacturing of the prototypes.
This poster present a system-level configuration optimization integrated with performance evaluation modules in the context of modeFRONTIER. The main goal is to propose a faster manufacturing system design procedure to study more potential configurations in less time, considering system’s different regional requirements. The methodology has been successfully used in the configuration of an automotive assembly line for cylinder head of Comau. With this platform it is possible to reduce design time under region dependent conditions, with first-time-right design (from 2-3 months to 1 week).
Spinal surgery consists in instrumentation through rods and pedicle screws.Before being implanted rods have to be contoured in order to fit the curvature of the spine.Two contouring processes are studied: one obtained by means of French bender (clinical,localized) and an homogeneous one(like preformed rods).FEM help to investigate the effects of contouring in terms of residual stresses and notches;furher fatigue tests are set,both experimentally and numerically,to recognise the most dangerous clinical configurations.Residual stresses play a role in fatigue resistance more than surface notches.
Augmented reality provides a real-time interactive and immersive 3D experience where real world objects are combined with computer-generated contextually relevant information and virtual objects. It is exploited in minimally invasive surgery, education, military aircraft and cultural heritage.
In the industrial field, thanks to augmented reality, the visualization of data, obtained by solving a set of partial differential equations with a Finite Element Method (FEM), over a particular object could allow the assessment of the multi-physical performance of a specific structure or component.
In the present work, in order to evaluate the deformation behaviour of a titanium alloy under superplastic conditions, an experimental-numerical approach was used. In particular, starting from Free Inflation Tests with a constant pressure profile and a pressure profile based on jumps between two different values, the strain rate sensitivity index (m) value was obtained by means of the inverse analysis based on a genetic algorithm. The subsequent comparison between the results of the numerical simulations implementing the data obtained from the inverse analysis and the experimental results show a good agreement.
The activity was originated in the framework of a collaboration between University of Pisa and Global Garden Products (GGP). The goal was to develop multilevel simulation and experimental tools aimed at characterizing the vibration behavior of a Lawn Tractor. These tools can be used to improve the comfort of the driver of the tractor and to avoid components resonance due to engine and blades excitations. A Semi-flexible MultiBody model and a Finite Element model were developed and successfully validated through comparison with experimental results.
Malignant melanoma is a highly aggressive tumor that causes more than 75% of skin cancer-related deaths. An early diagnosis of melanoma could significantly reduce the associated mortality.. A biomechanical analysis could help the early diagnosis of melanoma. According to literature studies, in fact, a modification on the mechanical properties of biological tissues occurs under pathological
This poster proposes an effective methodology for the fluid-dynamic optimization of the sliding spool of hydraulic proportional directional valves: the goal is the minimization of the flow forces, while keeping the operation features unchanged. The optimization was tested on an existing valve, and its experimental validation was successfully performed. The aim of this work is to extend the application range of these valves to higher values of pressure and flow rate, thus avoiding the employment of more expensive two stage configurations in the case of high-pressure conditions and/or flow rate.
Cardiac torsion was proved to be sensitive to pathological conditions. In this work, a multiscale computational model coupling a 3D biventricular structural model with lumped parameter models of the systemic and pulmonary circulation was developed to provide deep understanding of the torsional behaviour of the ventricles. Both physiological and pathological conditions have been investigated. The model outcomes highlight how the torsional pattern of the ventricles is affected by pathological conditions even in an early stage, thus encouraging the use of torsion in the clinical practice.
Left ventricular assist devices (LVADs) are affected by thrombus formation, in particular in the left ventricle (LV) – inflow cannula interface (LV apex). The study developed a CFD approach to simulate the cardiac cycle for healthy and pathological LV models (different contractilities, presence of cannula). Since wall shear stresses (WSSs) - mediated endothelial cells (ECs) activation can lead to platelets aggregation, the aim was to extract WSSs in the apical region to evaluate the ECs activation potential, which resulted higher for pathological LVs. WSS trends will be exploited in vitro.
Wall curvature is a widely used technique to passively enhance convective heat transfer and it is particularly effective in the thermal processing of highly viscous fluids. These geometries produce a highly uneven convective heat flux distribution along the circumferential coordinate, impacting on the performance of the fluid thermal treatment.
The high variation in the wall temperature causes an overheating of the fluid nearby the inner bend while at the outer bend it’s not heated as well. This
observation is very important if the fluid evolving inside the het exchanger is food, such as milk; in this case the sterilizing effect is not uniform in the cross-sectional
area. For this reason, to guarantee a lower level of the total bacteria charge, the fluid have to be overheated reducing the organoleptic property of the food and
increasing the energy consumption.
This work is aimed at numerically investigate the laminar fully developed flow in coiled tubes, considering a Newtonian, incompressible and with constant thermophysical properties fluid.
The numerical model has been experimentally validated by applying the Inverse Heat Conduction Problem approach; the comparison between numerical results and experimental data shows a good agreement, thus validating the CFD model.
The growing request of interactivity in real-time simulation for mechanical and civil engineering requires new methods for analysis. The first 3D virtual reality CAD software, offering design editing and review capabilities is presented in this work. The interaction is provided by a cost-effective tracking device (HTC Vive). The aim of this work is proving how virtual reality can reduce the development time while offering a better level of detail. This is demonstrated through a comparison between the traditional workflow and the proposed one on the same drawing task.
Polimi Motorcycle Factory designed and developed a motorcycle prototype to participate to the MotoStudent Competition.
This work focuses on the optimization of the chassis stiffness. The combination of the classical tubular structure with a carbon fiber cover, supported by an exagonal and diamond honeycomb core, turns into a single resisting sandwich structure. This technology increases the mechanical stiffness without altering the global structural behavior of the frame. The result is a thinner and lighter swing arm with added mechanical strength. The innovative design permits to get both an improvement of the performances of the vehicle, guaranteeing the necessary torsional, flexional and lateral stiffness, and the simplification of manufacturing process.
Iterative procedures of structural analysis and optimization, that exploited a set of commercial CAD and FE software, such as Creo, Abaqus and Ansys, lead to a versatile structure, whose performances stand out the other solutions available on the market, that is now ready for further developments.
The advantages of the research activity are appreciable also from the financial point of view.