Antonio Javier Gil

Swansea University | SWAN · Zienkiewicz Centre for Computational Engineering "ZCCE"

This manuscript introduces a novel Neural Network-based computational framework for constitutive modelling of thermo-electro-mechanically coupled materials at finite strains, with four key innovations: (i) It supports calibration of neural network models with various input forms, such as Ψnn(F,E0, θ), enn(F,D0, η), Υnn(F,E0, η), or Γnn(F,D0, θ), wi...

This paper introduces a novel Smooth Particle Hydrodynamics (SPH) computational framework that incorporates an Arbitrary Lagrangian Eulerian (ALE) formalism, expressed through a system of first-order conservation laws. In addition to the standard material and spatial configurations, an additional (fixed) referential configuration is introduced. The...

The paper introduces a computational framework using a novel Arbitrary Lagrangian Eulerian (ALE) formalism in the form of a system of first‐order conservation laws. In addition to the usual material and spatial configurations, an additional referential (intrinsic) configuration is introduced in order to disassociate material particles from mesh pos...

This paper introduces a metamodelling technique that employs gradient-enhanced Gaussian process regression (GPR) to emulate diverse internal energy densities based on the deformation gradient tensor F\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mat...

This paper introduces a metamodelling technique that leverages gradient-enhanced Gaussian process regression (also known as gradient-enhanced Kriging), effectively emulating the response of diverse hyperelastic strain energy densities. The approach adopted incorporates principal invariants as inputs for the surrogate of the strain energy density. T...

This paper presents a set of novel refined schemes to enhance the accuracy and stability of the updated Lagrangian SPH (ULSPH) for structural modelling. The original ULSPH structure model was first proposed by Gray et al. (Comput Methods Appl Mech Eng 190:6641–6662, 2001) and has been utilised for a wide range of structural analyses including metal...

The design of magnets for magnetic resonance imaging (MRI) scanners requires the numerical simulation of a coupled magneto-mechanical system where the effects that different material parameters and in-service loading conditions have on both imaging and MRI performance are key to aid with the design and the manufacturing process. To correctly captur...

A new computational framework for large strain elasticity in principal stretches is presented. Distinct from existing literature, the proposed formulation makes direct use of principal stretches rather than their squares that is, eigenvalues of Cauchy‐Green strain tensor. The proposed framework has three key features. First, the eigen‐decomposition...

This paper introduces a novel upwind Updated Reference Lagrangian Smoothed Particle Hydrodynamics (SPH) algorithm for the numerical simulation of large strain thermo-elasticity and thermo-visco-plasticity. The deformation process is described via a system of first-order hyperbolic conservation laws expressed in referential description, chosen to be...

A novel mixed framework and energy‐momentum consistent integration scheme in the field of coupled nonlinear thermo‐electro‐elastodynamics is proposed. The mixed environment is primarily based on a framework for elastodynamics in the case of polyconvex strain energy functions. For this elastodynamic framework, the properties of the so‐called tensor...

Typical computational techniques for vascular biomechanics represent the blood vessel wall via either a membrane, a shell, or a 3D solid element. Each of these formulations has its trade offs concerning accuracy, ease of implementation, and computational costs. Despite the widespread use of these formulations, a systematic comparison on the perform...

This paper presents a novel engineering strategy for the design of Dielectric Elastomer (DE) based actuators, capable of attaining complex electrically induced shape morphing configurations. In this approach, a multilayered DE prototype, interleaved with compliant electrodes spreading across the entire faces of the DE, is considered. Careful combin...

The use of Electro-Active Polymers (EAPs) for the fabrication of evermore sophisticated miniaturised soft robotic actuators has seen an impressive development in recent years. The incorporation of crystallographic anisotropic micro-architectures, within an otherwise nearly uniform isotropic soft polymer matrix, has shown great potential in terms of...

This paper presents a novel in-silico framework for the design of flexoelectric energy harvesters at finite strains using topology optimisation. The main ingredients of this work can be summarised as follows: (i) a micromorphic continuum approach is exploited to account for size dependent effects in the context of finite strains, thus permitting th...

The use of Electro-Active Polymers (EAPs) for the fabrication of evermore sophisticated miniaturised soft robotic actuators has seen an impressive development in recent years. This paper unveils the latest computational developments of the group related to three significant challenges presented in the in-silico modelling of EAPs, that are being exp...

This paper presents a vertex‐centred finite volume algorithm for the explicit dynamic analysis of large strain contact problems. The methodology exploits the use of a system of first order conservation equations written in terms of the linear momentum and a triplet of geometric deformation measures (comprising the deformation gradient tensor, its c...

The present paper presents a novel in-silico framework for the design of flexoelectric energy harvesters at finite strains using topology optimization. The main ingredients of this work can be summarised as follows: (i) a micromorphic continuum approach is advocated for to account for size dependent effects in the context of finite strains, hence,...

This paper analyses the viscoelastic up-scaling effects in electro-active polymers endowed with a micro-structure architecture in the form of a rank-one laminate. The principles of rank-n homogenisation and thermodynamical consistency are combined in the context of extremely deformable dielectric elastomers actuated well beyond the onset of geometr...

This paper presents a new Updated Reference Lagrangian Smooth Particle Hydrodynamics (SPH) algorithm for the analysis of large deformation isothermal elasticity and elasto-plasticity. Taking as point of departure a Total Lagrangian setting and considering as referential configuration an intermediate configuration of the deformation process, the equ...

The fabrication of evermore sophisticated miniaturised soft robotic components made up of Electro-Active Polymers (EAPs) is constantly demanding parallel development from the in-silico simulation point of view. The incorporation of crystallographic anisotropic micro-architectures, within an otherwise nearly uniform isotropic soft polymer matrix, ha...

The aim of this paper is the design of a new one-step implicit and thermodynamically consistent Energy-Momentum (EM) preserving time integration scheme for the simulation of thermo-electro-elastic processes undergoing large deformations. The time integration scheme takes advantage of the notion of polyconvexity and of a new tensor cross product alg...

The aim of this paper is the design of a new one-step implicit and thermodynamically consistent Energy-Momentum (EM) preserving time integration scheme for the simulation of thermo-electro-elastic processes undergoing large deformations. The time integration scheme takes advantage of the notion of polyconvexity and of a new tensor cross product alg...

This paper analyses the viscoelastic up-scaling effects in electro-active polymers endowed with a micro-structure architecture in the form of a rank-one laminate. The principles of rank-n homogeneisation and thermodynamical consistency are combined in the context of extremely deformable dielectric elastomers actuated well beyond the onset of geomet...

This paper presents a novel in-silico tool for the design of complex multilayer Dielectric Elas-tomers (DEs) characterised by recently introduced layer-by-layer reconfigurable electrode meso-arquitectures. Inspired by cutting-edge experimental work at Clarke Lab (Harvard) [21], this contribution introduces a novel approach underpinned by a diffuse...

This paper presents mathematical models of supersonic and intersonic crack propagation exhibiting Mach type of shock wave patterns that closely resemble the growing body of experimental and computational evidence reported in recent years. The models are developed in the form of weak discontinuous solutions of the equations of motion for isotropic l...

This paper presents a novel Smooth Particle Hydrodynamics computational framework for the simulation of large strain fast solid dynamics in thermo-elasticity, with a tailor-made implementation into the modern CFD open source package "OpenFOAM". The formulation is based on the Total Lagrangian description of a system of first order conservation laws...

This paper introduces a new Incremental Updated Lagrangian Smooth Particle Hydrodynamics (SPH) computational framework in the form of a system of first order conservation laws. Specifically, the linear momentum conservation equation is solved in an incremental manner in conjunction with a set of incremental geometric conservation laws for the minor...

Designing engineering components that make optimal use of materials requires consideration of the nonlinear static and dynamic characteristics associated with both manufacturing and working environments. The modeling of these characteristics can only be done through numerical formulation and simulation, which requires an understanding of both the t...

This paper presents a novel in-silico tool for the design of complex multilayer Dielectric Elas- tomers (DEs) characterised by recently introduced layer-by-layer reconfigurable electrode meso-arquitectures. Inspired by cutting-edge experimental work at Clarke Lab (Harvard), this contribution introduces a novel approach underpinned by a diffuse inte...

This paper presents a novel Smooth Particle Hydrodynamics computational framework for the simulation of large strain fast solid dynamics in thermo-elasticity. The formulation is based on the Total Lagrangian description of a system of first order conservation laws written in terms of the linear momentum, the triplet of deformation measures (also kn...

This paper presents a novel computational framework for the in silico analysis of rank-one multilayered electro-active polymer composites exhibiting complex deformation patterns. The work applies the principles of rank-n homogenisation in the context of extremely deformable dielectric elastomers actuated beyond the onset of geometrical instabilitie...

This paper presents a new Smooth Particle Hydrodynamics computational framework for the solution of inviscid free surface flow problems. The formulation is based on the Total Lagrangian description of a system of first-order conservation laws written in terms of the linear momentum and the Jacobian of the deformation. One of the aims of this paper...

In Parts I (Bonet et al., 2015) and II (Gil et al., 2016) of this series, a novel computational framework was presented for the numerical analysis of large strain fast solid dynamics in compressible and nearly/truly incompressible isothermal hyperelasticity. The methodology exploited the use of a system of first order Total Lagrangian conservation...

The aim of this paper is the design a new one-step implicit and thermodynamically consistent Energy–Momentum (EM) preserving time integration scheme for the simulation of thermo-elastic processes undergoing large deformations and temperature fields. Following Bonet et al. (2020), we consider well-posed constitutive models for the entire range of de...

Manufacturing new Magnetic Resonance Imaging (MRI) scanners represents a computational challenge to industry, due to the large variability in material parameters and geometrical configurations that need to be tested during the early design phase. This process can be highly optimised through the employment of user-friendly computational metamodels c...

This paper presents a novel computational approach for SIMP-based Topology Optimisation (TO) of hyperelastic materials at large strains. During the TO process for structures subjected to very large deformations, and especially in the presence of intermediate density regions, the standard Newton-solver (or its arc length variant) have been reported...

The design of a new MRI scanner requires multiple numerical simulations of the same magneto‐mechanical problem for varying model parameters, such as frequency and electric conductivity, in order to ensure that the vibrations, noise and heat dissipation are minimized. The high computational cost required for these repeated simulations leads to a bot...

This paper presents a novel computational approach for SIMP-based Topology Optimisation (TO) of hyperelastic materials at large strains. The paper demonstrates that the stabilisation technique put forward in [1], initially devised to alleviate numerical instabilities inherent to level-set TO, can be effectively exploited in a very different context...

This project is part of the Marie Skłodowska-Curie ITN-EJD ProTechTion funded by the European Union Horizon 2020 research and innovation program with grant number 764636.

Latest developments in high-strength Magnetic Resonance Imaging (MRI) scanners with in-built high resolution, have dramatically enhanced the ability of clinicians to diagnose tumours and rare illnesses. However, their high-strength transient magnetic fields induce unwanted eddy currents in shielding components, which result in fast vibrations, nois...

The classical Smooth Particle Hydrodynamics (SPH) Lagrangian formalism is well-known to suffer from a number of severe drawbacks, namely: (1) hour-glassing and spurious pressure, (2) numerical issues associated with conservation, consistency, stability and convergence and (3) the reduced order of convergence for derived variables (e.g. stresses and...

This paper introduces a novel computational approach for level-set based topology optimisation of hyperelastic materials at large strains. This, to date, is considered an unresolved open problem in topology optimisation due to its extremely challenging nature. Two computational strategies have been proposed to address this problem. The first strate...

In the present contribution new approaches for the design of structure preserving time integrators for nonlinear coupled problems are proposed. Polyconvexity inspired energy functionals are obtained by using the rediscovered tensor cross product which greatly simplifies the algebra, see [1]. In this connection an extended kinematic set, consisting...

Building upon previous work developed by the authors [1, 2, 3], this paper will present an upwind Smooth Particle Hydrodynamics (SPH) algorithm for a first order conservation law framework in large strain thermo-elasticity. In this work, a system of conservation equations will be expressed in terms of the linear momentum and the minors of the defor...

The computational modelling of the heart motion within a cardiac cycle is an extremely challenging problem due to (a) the complex multi-scale interaction that takes place between the electrophysiology and electrochemistry at cellular level and the macro-scale response of the heart muscle, and (b) the large deformations and the strongly anisotropic...

Well-established computational techniques, such as the Finite Element, Finite Volume or Discontinuous Galerkin methods, rely on the tessellation of the domain of interest into a number of interconnected non-overlapping elements or control volumes (the so-called computational mesh). Despite their enormous success from the modelling standpoint, these...

Please find the abstract of this poster at this location: https://congress.cimne.com/admos2019/frontal/Doc/PosterSession/6-Di_Giusto.pdf Do not hesitate to contact me (Thomas B. J. Di Giusto) if you want to discuss about this work.

The audio recording of the talk can be found here: https://youtu.be/nKSlHcTnMIg

Transient magnetic fields are generated by the gradient coils in an MRI scanner and induce eddy currents in their conducting components, which lead to vibrations, imaging artefacts, noise and the dissipation of heat. Heat dissipation can boil off the helium used to cool the super conducting magnets and, if left unchecked, will lead to a magnet quen...

Within the group of immersed computational methodologies [1;2;3] which can be employed for the numerical simulation of fluid-structure interaction (FSI) problems, the multi-phase ‘one-fluid’ formulation was recently introduced [4;5] to enable the modelling of immersed rigid bodies as an additional physical phase of the coupled fluid-structure syste...

A family of numerical models for the phenomenological linear flexoelectric theory for continua and their particularisation to the case of three-dimensional beams based on a skew-symmetric couple stress theory is presented. In contrast to the standard strain gradient flexoelectric models which assume coupling between electric polarisation and strain...

In Ortigosa et al. (2018), the authors presented a new family of time integrators for large deformation electromechanics. In that paper, definition of appropriate algorithmic expressions for the discrete derivatives of the internal energy and consideration of multi-variable convexity of the internal energy was made. These two ingredients were essen...

This paper presents an explicit vertex centred finite volume method for the solution of fast transient isothermal large strain solid dynamics via a system of first order hyperbolic conservation laws. Building upon previous work developed by the authors, in the context of alternative numerical discretisations, this paper explores the use of a series...

This paper presents a novel computational framework for the numerical simulation of the electromechanical response of the myocardium during the cardiac cycle. The paper presents the following main novelties. (1) Two new mixed formulations, tailor-made for active stress and active strain coupling approaches, have been developed and used in conjuncti...

An industry-driven computational framework for the numerical simulation of large strain explicit solid dynamics is presented. This work focuses on the spatial discretisation of a system of first order hyperbolic conservation laws using the cell centred Finite Volume Method [1, 2, 3]. The proposed methodology has been implemented as a parallelised e...

In previous work (Lee et al., 2016, 2017), Lee et al. introduced a new Smooth Particle Hydrodynamics (SPH) computational framework for large strain explicit solid dynamics with special emphasis on the treatment of near incompressibility. A first order system of hyperbolic equations was presented expressed in terms of the linear momentum and the min...

This paper will extend the new conservation law formulation of solid dynamics presented by the authors in References [1, 2, 3] to the field of thermo-elasticity and thermo-plasticity. In order to account for thermal effects, the total energy conservation law (also known as first law of thermodynamics) will be incorporated to the set of physical law...

The paper presents a new computational framework for the numerical simulation of fast large strain solid dynamics, with particular emphasis on the treatment of near incompressibility. A complete set of first order hyperbolic conservation equations expressed in terms of the linear momentum and the minors of the deformation (namely the deformation gr...

My presentation at the European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS) 2018 in Glasgow, Scotland.