Dr. Szabolcs Berezvai

Assistant professor

Department of Applied Mechanics
Budapest University of Technology and Economics

"Everything should be made as simple as possible, but not simpler."
(Albert Einstein)

Modelling and simulation of viscous-elastic-plastic polymers

foam My main field of research is the mechanical modelling and simulation of polymers and polymer foam materials. Polymer foams are special cellular materials, which are applied widely in the industry due to their favourable mechanical properties (e.g. packaging, mattresses, sport shoes, etc...). The my research on the mechanics of polymer foams began on BSc level when I investigated the pure elastic large strain hyperelastic material models. During my MSc studies I have studied the time-dependent large strain visco-hyperelastic modelling approach. Currently, on PhD level, my research topic is: Development of viscous-elastic-plastic constitutive models

The mechanical behaviour of polymers can show both elastic, plastic and viscous deformations in addition to large strains. The number of constitutive equations that describe such mechanical properties is limited. Using the available built-in material models in commercial finite element softwares, the modelling of this complex behaviour is highly inaccurate, albeit the industrial need is significant (e.g. thermoforming of polymers). The aims of current research approaches is to develop complex material models and their numerical implementation. During my research I've investigated the mechanical behaviour and the modelling approaches of open- and closed-cell polymer foams, memory foams, thermoplastic microcellular foams and the impact of airsoft pellets.

Keywords: Constitutive equations, viscous-elastic-plastic deformations, Finite Element Analysis (FEA), finite strains, continuum mechanics

Application of Finite Element Simulations and techniques

Our state-of-the-art computer infrastructure enables us to use high-precision complex computer simulations to solve engineering problems. At the same time, developing the proper finite element model (FEM) is an extremely complex, challenging task that is actively investigated field. During my research on FEM, I investigate the applicability of the so-called Coupled Eulerian-Lagrangian description (CEL) for the numerical modeling of chip formation and rolling. In addition to these special techniques, one of the most important parts of building an accurate FEM model is selecting the proper constitutive and contact model, that is investigated through the simulation of airsoft ball impacts, compression of aluminum and polymer foams, sports ball impacts (ping-pong, pressurized tennis balls) and human sitting on foams.

Keywords: Finite element simulation, CEL, contact models , chip formation, rolling, human sitting

High-speed camera measurements

High-speed camera measurements make it possible to investigate mechanical phenomena happening in a very short time. One possible field of application is the investigation of machine-tool vibrations and chip formation process, which have usual time scale of microseconds. It should be emphasized that high-speed camera measurements require a careful design, while the recordings should be analysed using image processing methods. My research the SIREN ERC Project focuses on the experimental investigation of chip formation using high-speed camera in order to evaluate the performace of the theoretical models.

Keywords: Image processing, machine-tool vibrations, chip formation

Research in pedagogy

In addition to mechanics, I also participate in researches in the field of math teaching at univesity level and talent management. The goal of this project is to handle the students’ varying level of knowledge and ensure coaching, practising and talent development by applying unconventional educational methods in the programs of regular subjects of mathematics. The kernel of the method is a multi-step complex education structure, which is based on continuous testing. The goal of our method is to motivate all students for continuous self-development and continuous learning. This form of education was supplemented in the last year with the introduction of the online-education.

Keywords: talent management, test-effect, methodology of math teaching, online education

Own research programmes
Date Programme Title of programme
2019-2020 Scolarship for the Young Talents of Hungary
Ministry of Human Capacities
Mechanical modeling and simulation of the adhesion mechanism of geckos
2018-2019 New National Excellence Program
Ministry of Human Capacities
Experimental and numerical investigation of the applicability of the viscoplastic constitutive models in case of modelling chip formation processes
2017-2018 New National Excellence Program
Ministry of Human Capacities
Experimental and numerical investigation of the applicability of constitutive models for thermoforming
2016-2017 New National Excellence Program
Ministry of Human Capacities
Mechanical modelling of thermoforming process in case of thermoplastic polymer foam materials
Participation in research programmes
Date Programme Title of programme Principal investigator
2019-2020 European Research Council (ERC) Proof of Concept ProExcer: Projectile Exciter for Noiseless Environment dr. Gábor STÉPÁN
2018-2021 National Research, Development and Innovation Office (NKFIH), Research projects initiated by young researchers (FK) Mechanics of gecko-inspired dry adhesives dr. Attila KOSSA
2014-2019 European Research Council (ERC) Advanced Grant Stability Islands: Performance Revolution in Machining dr. Gábor STÉPÁN
2013-2016 Hungarian Scientific Research Found (OTKA) Constitutive modelling of cellular solids dr. Attila KOSSA

Experiences abroad
Date Host Title Location
May 16-20, 2016 ECCOMAS & Scuola Universitaria Superiore Pavia: CeSNA, IMATI, Dipartimento di Matematica, DICAr Nonlinear computational solid and structural mechanics Pavia, Italy
July 03-07, 2017 International Centre for Mechanical Sciences (CISM) Mechanics of Liquid and Solid Foams Udine, Italy
Septembre 03-04, 2017 International Centre for Numerical Methods in Engineering (CIMNE) 14th Short Course on Computational Techniques for Plasticity Barcelona, Spanyolország
May 28 - June 1, 2018 International Centre for Mechanical Sciences (CISM) Modelling and Simulation of Tribological Problems in Technology Udine, Italy

Database Link
Hungarian Database of Publications (MTMT) MTMT-database
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