Andrea Chiappa

University of Rome Tor Vergata | UNIROMA2 · Department of Industrial Engineering

The DEMO tokamak exhibits extraordinary complexity due to the constraints and requirements pertaining to different fields of physics and engineering. The multidisciplinary nature of the DEMO system makes its design phase extremely challenging since different and often opposite requirements need to be accounted for. Toroidal field (TF) coils generat...

Digital image correlation methods allow the determination of the displacement (and thus the strain) field of a target by picture comparisons, without the application of strain gauges or other invasive devices. Homologous sites are mapped from the undeformed to the deformed configuration, and displacements retrieved at a cloud of points in a scatter...

Thin plates are very often employed in a context of large displacements and rotations, for example, whenever the extreme flexibility of a body can replace the use of complicated kinematic pairs. This is the case of the flexible Printed Circuit Boards (PCBs) used, for example, within last-generation foldable laptops and consumer electronics products...

The Modified Blalock Taussig Shunt (MBTS) is one of the most common palliative operations in case of cyanotic heart diseases. Thus far, the decision on the position, size, and geometry of the implant relies on clinicians’ experience. In this paper, a Medical Digital Twin pipeline based on reduced order modeling is presented for fast and interactive...

Fluid-Structure Interaction (FSI) can be investigated by means of non-linear Finite Element Models (FEM), suitable to capture large deflections of structural parts interacting with fluids, and Computational Fluid Dynamics (CFD). High fidelity simulations are obtained using the fine spatial resolution of both the structural and fluid computational g...

Sommario In questo studio si mostra come la modellazione FEM possa essere utilizzata per simulare l'emissione di onde acustiche, causata da un'estensione locale o dalla nascita di un difetto nella struttura. Il metodo di controllo non distruttivo basato sulle emissioni acustiche è alla base di sistemi di monitoraggio accurati e affidabili. L'elabor...

A two-dimensional problem of elastic wave propagation in a rectangular solid is considered. It is first approached using the classical apparatus of mathematical physics, with a fully analytical model produced as the result. The same system is then analysed numerically using two commercial finite element software packages, COMSOL and ANSYS APDL, wit...

Fluid-Structure Interaction (FSI) can be investigated by means of non-linear Finite Element Models (FEM), suitable to capture large deflections of structural parts interacting with fluids, and Computational Fluid Dynamics (CFD). High fidelity simulations are obtained using the fine spatial resolution of both the structural and fluid computational g...

CAD and CAE model update on manufactured shapes is a key process in the industry 4.0, where design, manufacturing and maintenance are integrated elements. Digital Twin models, together with Reverse Engineering (RE) techniques, allow tracking components performances during production and verifying the compliance with design requirements during the c...

Several experimental databases of aeroelastic measurements performed on aircraft wing models are available for the validation of fluid–structure interaction (FSI) numerical methodologies. Most of these databases are used to model scaled systems focusing primarily on aerodynamic aspects, rather than on structural similitude with a full-scale model....

Radial basis functions (RBFs) based mesh morphing allows to adapt the shape of a computational grid onto a new one by updating the position of all its nodes. Usually nodes on surfaces are used as sources to define the interpolation field that is propagated into the volume mesh by the RBF. The method comes with two distinctive advantages that makes...

High fidelity Fluid-Structure Interaction (FSI) can be tackled by means of non-linear Finite Element Models (FEM) suitable to capture large deflections of structural parts interacting with fluids and by means of detailed Computational Fluid Dynamics (CFD). High fidelity is gained thanks to the spatial resolution of the computational grids and a key...

Often the employment of the full potentialities of laminated composite materials is restrained by the scarceness of cost-effective simulation strategies in the design stage. Albeit cheap modelling techniques exist, they typically prove ineffective in retrieving interlaminar stresses, the first responsible for the damage of laminates. In this paper,...

The European DEMO, i.e. the demonstration fusion power plant designed in the framework of the Roadmap to Fusion Electricity by the EUROfusion Consortium, is approaching the end of the pre-conceptual design phase, to be accomplished with a Gate Review in 2020, in which all DEMO subsystems will be reviewed by panels of independent experts. The latest...

Fractal analysis appears to be a relevant tool toward the interpretation of acoustic emissions signals related to the stress and damage of the material and this paper shows how it can be adopted for health monitoring of various structures. The fractal dimension quantifies the order/disorder of the signals and is correlated to the applied stress/pre...

The acoustic emission (AE) method is well studied for its capability to detect and locate discontinuity that evolve in time, when a pressure tank is charged with a greater load than the usual one. When the discontinuity is a crack the AE is able to follow the nucleation and the propagation of the defect in the material. For this paper, experiment o...

The study and design of cyclically loaded structures cannot neglect the evaluation of their fatigue behavior. Today numerical prediction tools allow adopting, in various industrial fields, refined and consolidated procedures for the assessment of cracked parts through analyses based on fracture mechanics. An high level of detail can be obtained thr...

The capability to reduce the structural weight of aircrafts, and consequently the fuel consumption, is related to the accuracy of numerical tools and to the efficiency of design methodologies available. In particular, the capability to model the interaction of the several mechanisms involved in physics phenomena represents a key point in the develo...

This paper presents a method of interpolation and regularisation of finite element (FE) results based on radial basis functions (RBF) capable to upscale at a finer resolution the displacement fields and, accordingly, the strains and the stresses obtained with a coarse mesh. RBF interpolation of nodal displacements supplies an analytical approximati...

The paper presents the multi-physics study of the Toroidal Field (TF) coils of the DTT device, as defined according to the design of the “Divertor Tokamak Test facility Interim Design Report” also known as the “green book”. TF coils winding packs are constituted by 5 Double-Pancakes (DP), enclosed into a SS316LN casing for structural reinforcement....

In the analysis and design of racing competition cars, numerical tools allow to investigate a wide range of solutions in short time and with high confidence in results. The great available computational power permits to combine simulation software so that different physics involved can be tackled at the same time. An important class of multi-physic...

This paper presents a method able to upscale finite element (FE) results obtained for coarse meshes of 2D models at a higher resolution, using both radial basis functions (RBF) and balance equations. RBF supply a smooth function from nodal displacements. In addition to FE nodes, RBF interpolation embeds a certain number of additional points, for wh...

In this paper a method to improve the stress state on a 2D finite element (FE) Q1 coarse mesh for fracture mechanics applications is shown. Radial Basis Functions (RBF) are employed synergically with balance equations to reduce the interpolation error and improve results extracted from the coarse FEM models. In addition to FE nodes, RBF interpolati...

A common issue in Multiphysics analysis regards a reliable way for loose couplings, because the same object is modelled using different mesh refinements, each one suited for a proper field of physics. Output data originating in a simulation environment are transferred as input data to a different model to run a new analysis. It is strongly desirabl...

The design of the superconducting magnet system of the European DEMO fusion reactor is currently being pursued in the framework of the EUROfusion Magnets Work Package. Three alternative winding pack (WP) options for the toroidal field coils (TFCs) are being proposed by different research units, each featuring a different conductor manufacturing tec...

Adjoint solvers are acquiring nowadays a growing importance in shape optimization especially when dealing with fluid dynamic applications; their use for structural optimization is however still limited. In this work an optimization workflow based on the synergic use of a structural continuum-discrete adjoint variable solver and the commercial morph...

Damage tolerant design requires the implementation of effective tools for fracture mechanics analysis suitable for complex shaped components. FEM methods are very well consolidated in this field and reliable procedures for the strength assessment of cracked parts are daily used in many industrial fields. Nevertheless the generation of the computati...

In this paper a novel approach to handle the structural design and automate the shape optimization of an automotive wheel rim in the ANSYS Workbench environment is proposed. The aim of the study is to optimize an aluminium wheel rim taking into account the testing conditions dictated by a protocol conceived to get the approval for the certification...

Shape functions provide the deformation field inside a finite element from the nodal displacements: however it is known that this procedure entails a continuity issue. In this paper we propose a postprocessing tool based on radial basis functions (RBFs) taking as input the results of FEM analyses. This strategy uses RBFs to interpolate the nodal di...