Research projects

When metallic components become very small, their mechanical behaviour may change dramatically. Thin wires, micro-devices and small-scale specimens can become stronger than expected from conventional theories. In other words, at very small scales, “smaller” does not simply mean “weaker”: the size of the component itself becomes part of the mechanical response.

This happens because plastic deformation in metals is governed by the motion and interaction of dislocations. When the dimensions of the specimen approach the micrometre scale, boundaries, grain structure and non-uniform deformation strongly affect how plasticity develops. Classical plasticity models, which work very well at the macroscopic scale, do not include an intrinsic material length and therefore cannot fully capture these size-dependent effects.

My research develops advanced computational models capable of describing this behaviour. These models enrich classical plasticity by introducing internal length scales and additional mechanical effects related to non-uniform plastic deformation. The aim is to predict how metallic materials respond when the microstructure and the size of the component play a decisive role.

This research has applications in the simulation and design of micro-scale metallic components, thin wires, miniaturized devices, sensors, connectors and small structural parts, where reliability depends on the ability to predict strength, hardening and cyclic response at small scales. More broadly, it contributes to the development of computational tools for engineering problems in which classical local plasticity is no longer sufficient.

Keywords: strain-gradient plasticity, distortion-gradient plasticity, size effects, dislocations, finite element modelling, cyclic loading.

When materials start to fail, deformation often concentrates in narrow zones. In soils, rocks, concrete, metals or damaged materials, these zones may become the place where cracks, shear bands or failure mechanisms develop.

This is a major challenge for numerical simulations. In standard finite element models, the predicted width and shape of these localized zones may depend too much on the mesh used in the calculation. In other words, the simulation may start to describe the numerical discretization rather than the actual material behaviour.

My research aims to overcome this limitation by developing enhanced continuum models. These models introduce additional mechanical information into the material description, allowing the simulation to account for internal length scales and for the energetic cost of highly localized deformation.

In particular, I work on micropolar and Cosserat-type continua, including models with deformable directors. These theories make it possible to describe localization in a more objective and physically meaningful way, so that the formation and evolution of localized zones are governed by material parameters rather than by the finite element mesh.

This research is relevant for the simulation of failure in geomaterials, foundations, quasi-brittle materials and structural components where softening, damage, shear bands or collapse mechanisms play a central role.

Keywords: generalized continua, Cosserat models, micropolar continua, deformable directors, localization, softening, damage, finite element modelling.

Predicting the behaviour of geomaterials is one of the most challenging tasks in computational mechanics. Soils, rocks, concrete and quasi-brittle materials may respond very differently under compression, shear and tension, and their behaviour is often governed by pressure dependence, nonlinear plasticity, softening and strain localization.

When these phenomena are not properly described, numerical simulations may become unstable or misleading. In particular, deformation may collapse into artificially narrow bands whose width is controlled by the finite element mesh rather than by the material itself. This is a major limitation when computational models are used to assess failure mechanisms in geotechnical and structural applications.

My research aims to overcome these limitations by developing advanced constitutive models and robust numerical algorithms for geomaterials. The work includes the formulation of smooth, convex and mechanically consistent yield and failure criteria, the treatment of non-associated plastic flow, pressure and Lode-angle dependence, and the development of efficient implicit integration procedures.

The research also explores generalized continuum approaches, including micropolar and Cosserat formulations, as a way to introduce internal length scales into the material model. This makes it possible to describe localization in a more objective and physically meaningful way, reducing mesh dependence and improving the predictive value of nonlinear simulations.

The broader objective is to build computational models that are not only mathematically consistent, but also useful for understanding and predicting real engineering problems involving geomaterials, failure and instability.

Keywords: geomaterials, elastoplasticity, yield and failure criteria, non-associated plasticity, softening, localization, Cosserat models, finite element modelling.

Ionic Polymer Metal Composites are soft electroactive materials that can bend when an electric voltage is applied. Conversely, they can generate an electrical signal when they are mechanically deformed. This two-way behaviour makes them attractive for flexible actuators, sensors and bio-inspired devices.

Their response is governed by a complex interaction between mechanics, electrostatics, ion transport and solvent diffusion. When a voltage is applied, ions and solvent redistribute inside the polymeric membrane, producing swelling, internal stresses and macroscopic bending. Capturing this behaviour requires a genuinely multiphysics model.

My research in this field focuses on the electro-chemo-poro-mechanical modelling of IPMCs. The aim is to develop finite element formulations capable of describing actuation and sensing within a unified framework, accounting for large deformations, electric fields, ionic transport, solvent migration and electrochemical boundary conditions.

A key part of this work is the identification of material parameters from experimental data. This is essential to transform the theoretical model into a predictive computational tool that can be used to simulate real devices under different operating conditions.

Applications include soft actuators, flexible sensors, bio-inspired robotics, biomedical micro-devices and smart systems where electrical signals and mechanical deformation are strongly coupled.

Keywords: Ionic Polymer Metal Composites, IPMCs, electroactive polymers, electro-chemo-poro-mechanics, actuation, sensing, ion transport, solvent diffusion, finite element modelling.

Syntactic foams are advanced lightweight composite materials made of hollow microspheres embedded in a polymeric matrix. Their main advantage is the combination of low density and good mechanical performance, which makes them attractive for marine, naval, aerospace and other weight-sensitive applications.

Predicting their strength, however, is not straightforward. Their mechanical response depends on the interaction between the polymeric matrix, the hollow microspheres, their spatial distribution and the progressive failure of the microspheres themselves. Small changes at the microstructural level may significantly affect the macroscopic behaviour of the material.

My research in this field focuses on the development of micromechanical finite element models capable of linking the internal structure of syntactic foams to their overall mechanical response. These models make it possible to study how microsphere volume fraction, wall thickness, material properties and failure mechanisms influence compressive strength and damage evolution.

The goal is to support the design of lightweight composites with improved strength-to-weight performance. This is particularly relevant for components that must operate under demanding mechanical conditions, including hydrostatic loading, compression and high strain-rate events.

Applications include lightweight structural components, marine and underwater systems, aerospace structures, impact-resistant materials and advanced polymer composites.

Keywords: syntactic foams, lightweight composites, micromechanics, finite element modelling, representative volume elements, compressive failure, hydrostatic loading.

Many engineering processes involve metals undergoing very large deformations. This happens, for example, in forming, drawing, extrusion, rolling and other manufacturing operations, but also in severe loading conditions where the material experiences large plastic strains before failure.

At these deformation levels, plasticity cannot be treated as a simple extension of small-strain theories. The way elastic and plastic deformations are measured, updated and integrated in time becomes a central part of the model. Different finite-strain plasticity formulations may lead to similar engineering predictions in some cases, but they can differ significantly in terms of theoretical structure, numerical efficiency and ease of implementation.

My research in this field focuses on the formulation, numerical integration and critical assessment of finite-deformation elastoplastic models for metals. Particular attention is devoted to Eulerian approaches, in which the relevant elastic and plastic variables are described directly in the current configuration. These formulations can preserve much of the algorithmic simplicity of classical plasticity while remaining suitable for large-deformation problems.

The work also includes comparisons with other widely used approaches, such as hyperelastoplastic models based on multiplicative decompositions and hypoelastoplastic models commonly implemented in commercial finite element codes. The aim is to understand which formulations are most reliable, efficient and convenient for robust nonlinear simulations.

Applications include the simulation of metal forming processes, necking, shear-dominated deformation, drawing of bars and components, and more generally engineering problems in which metals undergo large plastic strains under complex loading conditions.

Keywords: finite-deformation plasticity, large strains, Eulerian formulations, elastoplasticity, Lode-angle dependence, numerical integration, finite element modelling, metal forming.

Metal drawing is a manufacturing process in which wires, bars or plates are pulled through dies to reduce their cross-section and obtain the desired final shape. It is widely used in the production of metallic components, but its design requires careful control of die geometry, friction conditions, material hardening and process forces.

Finite element simulations can provide detailed information about stresses, strains and residual effects, but they may be computationally demanding when many process parameters have to be explored. Analytical models offer a complementary tool: they provide fast estimates of the drawing force and help identify promising process configurations before performing more detailed numerical analyses.

My research in this field focuses on the development of simplified analytical solutions for cold drawing processes, based on plasticity theory and limit analysis. These models aim to capture the main mechanical features of the process while remaining sufficiently simple to be used in preliminary design and optimization.

The goal is to combine the speed of analytical estimates with the accuracy of numerical simulations, supporting a more efficient design of metal forming processes and reducing the number of costly trial-and-error analyses.

Applications include wire drawing, bar drawing, plate drawing, die design, process optimization and preliminary estimation of forming forces.

Keywords: metal drawing, cold forming, analytical solutions, plasticity theory, limit analysis, drawing force, die design, process optimization.

Sound is not only a wave propagating through air: in many engineering problems it is strongly coupled with the vibration of structures. Panels, walls, acoustic devices and lightweight components may vibrate under acoustic excitation, while their motion in turn modifies the surrounding sound field.

This interaction is especially important when predicting sound insulation, acoustic comfort and the performance of noise-control devices. Simplified models are often useful, but they may become insufficient when the geometry, the structural response or the acoustic excitation are complex.

My research in this field focuses on numerical and analytical models for acoustic fluid-structure interaction. Finite element simulations are used to describe the coupled response of vibrating structures and acoustic fields, with particular attention to flat panels, sound transmission and low-frequency acoustic behaviour.

Part of this work has also addressed the design of acoustic correction devices for rooms intended for music listening. In this context, perforated panels and resonant systems can be used to reduce low-frequency resonances and improve the acoustic response of the room.

The goal is to develop computational tools that help predict and improve the acoustic performance of panels, devices and spaces, combining physical insight, numerical modelling and practical design criteria.

Applications include sound insulation of panels, acoustic correction of listening rooms, low-frequency resonance control, noise reduction devices and vibro-acoustic design.

Keywords: acoustic fluid-structure interaction, vibro-acoustics, finite element modelling, sound transmission, sound reduction index, perforated panels, acoustic correction, low-frequency resonances.