People
prof. Ing. Ondřej Jiroušek, Ph.D.

Ing. et Ing. Radim Dvořák; Ing. Jan Falta; prof. Ing. Ondřej Jiroušek, Ph.D.; Ing. Ján Kopačka, Ph.D.; Ing. Petr Koudelka, Ph.D.

The project is aiming to control the stress wave propagation in additively produced metal components composed of at least two different metals with spatially shaped and multiple interfaces produced by laser powder bed fusion. This enables to control of internal arrangement and shaping of the interface between the two materials. Dynamic loading with different strain rates using Hopkinson pressure bars will be used to describe the stress wave propagation and kinetic energy absorption. At the same time, theoretical and numerical modelling of wave reflection/transmission will be performed on various geometrically arranged interfaces. Innovative numerical tools for advanced multi-material optimization of nested spatial structures will be developed for wave process control. The results will answer the questions of whether it is possible to control the propagation of stress waves by means of multi-material 3D metal printing, and what geometrical and mechanical parameters have a fundamental influence on the attenuation and concentration of stress waves.

2024 - 2026

Standard projects

Ing. Tomáš Doktor, Ph.D.; Ing. Jan Falta; Ing. Tomáš Fíla, Ph.D.

The unique feature of shear thickening fluid (STF), which shifts its phases from liquid state to solid state under dynamic loading, recently peaked attention in literature for shock absorbing systems or dashpots. Owing to phase shifting capability, employing STF as a vibration-damping system (VDS) can upgrade the performance of the structures under low probable dynamic actions (or accidental load). Therefore, a novel approach [i.e., STF-damped structural system] can tune the deficient structural system to a resilient one. Namely, an efficient, viable, and feasible rehabilitation solution for deficient structures can enhance the seismic performance of these structures by converting the kinetic energy of the shock into another energy form in the damper. To this end, the project proposes a novel approach, using STF to damp structural vibrations. Within the content of the project, STF working under a low strain rate and frequency is first synthesized. Then, the mechanical properties of the STF are obtained under dynamic load, which will be followed by a development of a damper filled with synthesized STF. Finally, real-time applications such as lab scale tests of STF dampers and computer simulations are targeted.

2024 - 2027

Program na podporu aplikovaného výzkumu a inovací SIGMA

prof. Ing. Ondřej Jiroušek, Ph.D.

The proposed projects deals with testing of the ultra high performance concrete (UHPC) under dynamic loading. This modern cementitous composite material has potential in wide range of applications such as civil engineering (buildings, bridges, tower blocks), parts of the transport infrastructure, or urban furniture. UHPC has excellent mechanical properties such as damage tolerance, fracture toughness and durability, which leads to possible use of this material in special application such as marine structures, underground spaces, nuclear waste containers, protection of critical infrastructure, mobile anti-vehicle barrier and national defence and military facilities. In this special applications is the material subjected to different modes of loading and different loading rates from creep, quasi-static to intermediate and high strain rates. Behaviour of the material in dynamics isn't properly described. Therefore is the proposed project subjected especially in testing of this material under elevated strain rate using a high speed motorized linear stage and Split Hopkinson Pressure/ Tensile Bar (SHPB/SHTB). Digital image correlation will be used to analyse the displacement and strain fields for support of the standard instrumentation of the device. Advanced methods of the instrumentation of these experimental devices include state-of-the-art lab-based in-situ X-ray imaging which allow insight into the deformation behaviour of the material. These results can be used for description of the internal effects and processes.

2023 - 2024

Studentská grantová soutěž ČVUT - SGS23/134/OHK2/2T/16

prof. Ing. Ondřej Jiroušek, Ph.D.

The proposed project deals with the development of innovative and robust numerical dynamics methods specialized for solving high-speed impact problems. In the first phases of the project, the objective will be to complete a finite element method (FEM) solver considering nonlinear material models and large deformations with an implemented method for domain (spatial) decomposition via Localized Lagrange Multiplier Method (LLM), which will allow robust parallelization of the computations. The benefits of parallelization lie in the potential to solve complex nonlinear problems of millions of degrees of freedom in acceptable time period. The LLM method will be applied for coupling domains of different dimensions (typically 1D and 3D), allowing the structure of modern materials to be directly modelled, rather than using homogenised constitutive models. In the area of time discretization, advanced methods for direct time integration will be developed. Namely, an asynchronous integration algorithm will be generalized to allow computations to be performed on individual domains with their own time step, and a procedure considering Helmholtz decomposition of the displacement field will be developed to separately compute longitudinal and shear waves that differ in phase velocity and hence in the critical time step that enters the computation. These procedures have a critical impact on the quality of the solution of dynamic impact problems using FEM and direct time integration, which is prone to dispersion. The synergy of parallel computation, mastered domain decomposition using LLM, and the use of innovative methods for direct time integration will enable direct and precise computation of materials of complex structures by large-scale numerical models, e.g., even with time-varying material parameters (piezoelectricity). In the advanced phases of the project, the primary focus will be on smooth particle hydrodynamics (SPH) method, material point method (MPM), particle finite e

2022 - 2024

Studentská grantová soutěž ČVUT - SGS22/196/OHK2/3T/16

Ing. Ticiano Costa Jordao, Ph.D.; Ing. Tomáš Javořík, Ph.D.; Ing. Vít Malinovský, Ph.D.; Ing. Luboš Nouzovský, Ph.D.; Ing. Simona Přikrylová, Ph.D.; doc. Ing. Lukáš Týfa, Ph.D.; Ing. David Vodák, Ph.D.

The project proposal sets a framework for strategic cooperation among key stakeholders of the rail sector. Under the umbrella of a rail Skills Alliance, businesses, education and training institutions, professional associations, and other partners together will develop and implement strategies to address skills gaps and shortage, by developing occupational profiles, vocational programmes and qualifications, as well as designing a long term action plan to be rolled out at the European, national and regional levels. After that, STAFFERS will also support the design and delivery of joint vocational training curricula, programmes and teaching and training methodologies, drawing on evidence of trends and skills needed in the rail sector. In addition, STAFFERS will explore, develop and implement approaches of education, training and skills development for cross-border railway traffic. In order to foster transnational mobility and exchange of various groups of learners and staff, the project will also develop and test cross-border student mobility schemes and work-based internships.

2021 - 2024

Projekty podpořené ze zahraničí (pracovní kód k dodatečnému upřesnění) - 621684-EPP-1-2020-1-IT-EPPKA2-SSA-B

Ing. Marcel Adorna; Ing. Tomáš Doktor, Ph.D.; Ing. Jan Falta; Ing. Tomáš Fíla, Ph.D.; Ing. Michaela Jurko; doc. Ing. Petr Zlámal, Ph.D.; Ing. Jan Šleichrt, Ph.D.

The goal of the project is to develop and experimentally validate a new structural panel for energy absorption applications with unique properties based on polymeric cellular core and nanocrystalline metal coating. The strain-rate sensitivity of the strut material (polymeric foam and auxetic) will be achieved by micro inertia of the coated framework showing a stretching- induced additional amount of energy dissipation. Design optimization of such a structure requires in-deep investigation of the deformation behavior for the given specific impact conditions. Advanced numerical modelling will be performed at all structural levels, from cell wall mechanics up to whole panel behaviour. For this, a combination of several experimental methods (micro-CT, static compression, drop tests, SHPB and gas gun experiments) will be used. The experimental results will be used to validate our FE models describing the deformation behaviour at small to high velocity impacts. The project is building upon our previous experiences with numerical/experimental optimization of metal foams and auxetics.

2019 - 2021

Standard projects

prof. Ing. Ondřej Jiroušek, Ph.D.

The proposed project is aimed at measurement and description of the mechanical behaviour of advanced materials (cell materials, auxetic structures, composite materials, etc.) at medium and high deformation rates using the experimental SHPB setup and its modifications. The dependence of material characteristics on deformation velocity is a key parameter in the assessment of material properties, whether for use in transport applications - absorption of impact deformation energy (deformation zones) or for protection of critical infrastructure. The project focuses on the methodology of measuring complex structures that will be able to absorb large amounts of kinetic energy and designing penetration experiments of these structures. Analysis of material behaviour at the impact site of the impactor is very challenging, as the sample of the material makes optical recording of the deformation difficult for application of digital image correlation (DIC). The project proposal deals with a concept of measurement and methodology using radiographic methods for examination and description of deformation at the site of impact in co-operation with currently running OP VVV project (Excellent research, call 19). The project is focused on the application of a new OHPB method for determining the behaviour of materials at impact loads. Furthermore, the project focuses on investigation of the deformation behaviour of materials under impact loads using X-rays. The project will study the use of two OHPB variants and utilization of the X-rays for recording the penetration of a projectile through the studied material. The results of the experiments will be used to describe the behaviour of materials under extreme loads and to develop numerical methods for simulating these processes using the Finite Element Method. The project thematically follows the national GAČR (GA15-15480S) project focused on modifying the SHPB setup and ties upon the achieved results.

2018 - 2019

Studentská grantová soutěž ČVUT - SGS18/155/OHK2/2T/16

prof. Ing. Ondřej Jiroušek, Ph.D.

The project is focused on implementation and development of advanced experimental methods for the assessment of mechanical properties of materials subjected to high strain-rate loading using Split Hopkinson pressure bar (SHPB). Key design features and instrumentation equipment of the existing SHPB (located at the Laboratory of the Department of Mechanics and Materials) will be upgraded and optimized for measurements of materials for energy absorption applications used in transportation industry. The upgrade of the key design features will allow for precise measurements with extensive deformation of low impedance materials and materials with complex inner structure with strain-rate sensitivity. The upgrade of the instrumentation equipment will allow for synchronized observation of the experiments using high-speed camera and recording of key parameters for an advanced corrections of the measured data. Moreover, software tools for estimation of the experiment input variables, automatized data recording and data export, calculation of the parameters for the correction of geometry imperfections, functions for correction of wave dispersion and attenuation, and for the analysis of stress dynamic equilibrium will be developed. Synergistic approach combining upgrade of the design, upgrade of the instrumentation equipment and application of the developed software tools will be used for the development of an advanced experimental device optimized for the measurement of dynamic properties of low impedance materials. The device will overcome the limitations of conventional SHPB setups that can not be used for reliable measurements of low impedance materials. In final part of the project a concept based on actual method called "Open Hopkinson Pressure Bar" (OHPB) will be introduced. OHPB working principle is similar to SHPB, however in OHPB striker bar is not employed and instrumented incident bar is used instead of striker for direct high speed impact on the specimen. OHPB is r

2017 - 2018

Studentská grantová soutěž ČVUT - SGS17/148/OHK2/2T/16

Ing. Tomáš Doktor, Ph.D.; prof. Ing. Ondřej Jiroušek, Ph.D.

Projekt je zaměřen na rozvoj laboratorního zázemí pro výzkumně zaměřené studijní programy na ČVUT FD.

2017 - 2023

Operational Programme – Research, Development and Education – Structural Funds EU - CZ.02.1.01/0.0/0.0/16_017/0002589

Ing. Tomáš Doktor, Ph.D.; prof. Ing. Ondřej Jiroušek, Ph.D.

Projekt je zaměřen na úpravu současných doktorských studijních programů a oborů a tvorbu programu zcela nového se zaměřením na Smart Cities. Nově vytvořený program reflektuje, stejně jako programy upravené, výzvy současnosti a především budoucnosti nejen v souladu se strategickými dokumenty ČR (RIS3 apod.) a požadavky průmyslových partnerů, ale také s přeměnou techniky a technologií a růstem měst, která budou plně využívat synergických efektů kombinace ICT prostředků a technických infrastruktur.

2017 - 2023

Operational Programme – Research, Development and Education – Structural Funds EU - CZ.02.2.69/0.0/0.0/16_018/0002565

Proposed project aims at developing new highly optimized structures taking advantage of negative Poisson''s ratio of its metal skeleton and strain rate sensitivity of the filling material which would make it a compound material with exceptional ability to absorb energy at almost constant pressure. The project will take advantage of the present-day optimization algorithms and modern experimental methods for the best structural design. The optimality will be sought using parametric FE modelling, quasi-static testing utilizing time-lapse micro-CT and dynamic testing for both moderate and high strain-rates using either drop-tests and Split Hopkinson Pressure Bar. The resulting auxetic structure filled with strain-rate sensitive material is expected to possess excellent stiffness-to-weight ratio and damping capacity and will be used in the design of lightweight, high velocity impact resistant sandwich panel with effective control of its anti-impact performance.

2015 - 2017

Standard projects

prof. Ing. Ondřej Jiroušek, Ph.D.; doc. Ing. Jitka Jírová, CSc.; Ing. Jiří Kunecký, Ph.D.; doc. Ing. Daniel Kytýř, Ph.D.; Ing. Jan Vyčichl, Ph.D.

Vědecké setkání účastníků z vysokých škol a vědeckých ústavů z České republiky a ze SRN ve dnech 28.5. a 30.5.2008 v konferenčním centru AV ČR - zámek Liblice u Mělníka. Symposium je zařazeno do kalendáře konferencí ČVUT a je zaměřeno na rozvoj experimentálních metod a výpočtového modelování v mechanice. Tato bilaterální symposia mají dlouholetou tradici a jsou pořádána od roku 1985 ve spolupráci s Bergische Universitat ve Wuppertalu v SRN pravidelně každé 2 roky a střídavě v SRN a České republice. Na odborné náplni symposia se podílí ÚTAM AV ČR, Česká společnost pro mechaniku a VDI/VDE-GESA. Jednacím jazykem je angličtina a každý účastník se musí zúčastnit aktivně s referátem, který je vydán ve sborníku sympozia. Cílem symposia je zajistit setkání a výměnu zkušeností zejména mezi mladými vědci z obou zemí a podpořit bilaterální vědeckou spolupráci. www.bilateral2008.fd.cvut.cz

2008 - 2008

IGS ČVUT - CTU0815216

prof. Ing. Ondřej Jiroušek, Ph.D.

Totální náhrada kyčelního kloubu je v dnešní době běžným ortopedickým výkonem. Při této operaci se využívá dvou různých typů acetabulárních komponent. Prvním typem je cementovaná acetabulární komponenta, která je do pánevní kosti připevněna kostním cementem a druhým typem je necementovaná acetabulární komponenta, která je do pánevní kosti zaražena, zašroubována nebo připevněna vruty. Cílem tohoto projektu je vytvoření vysoce detailních 3D MKP modelů pánevní kosti s cementovanou acetabulární komponentou. Modely se budou lišit v typu imperfekce cementové vrstvy a budou podrobeny kontaktní napěťové analýze. Výsledkem této analýzy bude zjištění pole napětí v pánevní kosti, které popisuje působení implantátu na kostní tkáň.

2007 - 2007

IGS ČVUT - CTU0709216

prof. Ing. Ondřej Jiroušek, Ph.D.

Poranění hlavy je nejčastější příčinou úmrtí v důsledku dopravní nehody. Pro aplikaci v průmyslu je nutné znát mechanismus poranění a podmínky, za kterých poranění nastane (kritérium poranění hlavy). Pro stanovení těchto podmínek se nabízí řešení pomocí modelování hlavy metodou konečných prvků. V průběhu řešení projektu budou vytvořeny MKP modely hlavy použitelné k simulaci dopravní nehody (nárazu hlavy) pro různé typy dopravních nehod. Výsledkem analýzy by měl být hlavně popis chování na rozhraní lebka-mozek. Důraz bude též kladen na testování vlastností motocyklistických a cyklistických přileb během nehody a jejich vliv na změnu podmínek, za kterých nastane poranění. MKP modely helem budou ověřeny pomocí experimentálních metod. Cílem projektu je na základě obdržených výsledků objasnit chování mozku během dopravní nehody a pokusit se o aplikaci zjištěných poznatků na zkoumání změny podmínek porušení při použití přilby v modelu.

2007 - 2007

IGS ČVUT - CTU0709016

Blanka Budská; prof. Ing. Ondřej Jiroušek, Ph.D.; doc. Ing. Jitka Jírová, CSc.

Vědecké setkání účastníků z vysokých škol a vědeckých ústavů z České republiky a ze SRN ve dnech 16. až 19.6.2004 v Táboře, které je zaměřeno na rozvoj experimentálních metod a výpočtového modelování v mechanice. Tato bilaterální symposia mají dlouholetou tradici a jsou pořádána od roku 1985 ve spolupráci s Bergische Universitat ve Wuppertalu, SRN pravidelně každé 2 roky a střídavě v SRN a České republice. Jednacím jazykem je angličtina a každý účastník se musí zúčastnit aktivně s referátem, který je vydán v anglickém sborníku sympozia. Cílem symposia je také zajistit setkání a výměnu zkušeností mezi mladými vědci z obou zemí a tak podpořit bilaterální vědeckou spolupráci. V referátech budou zastoupeny příspěvky z oblasti záznamu a vyhodnocování experimentálních dat, rozvoje a využití experimentálních metod a měřících zařízení v mechanice tuhých a poddajných těles a v biomechanice a vztahu experimentu a výpočtového modelování (hybridní metoda).

2004 - 2004

IGS ČVUT - CTU0416516