People
Ing. Tomáš Fíla, Ph.D.

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

Ing. Jan Falta; Ing. Nela Krčmářová; Ing. Jan Šleichrt, Ph.D.

Flash X-ray system and high speed X-ray imaging methods will be used to investigate the internal processes in the materials during dynamic loading. The developed experimental equipment will be employed for investigation in field of modern materials for ballistic and impact protection, personal protective equipment or aerospace/space applications, e.g., sandwiches, composite panels and metamaterials, and to characterize their fundamental mechanical processes like failure and fracture behavior, wave propagation and constituent materials interaction. Significant part of research will be aimed on experimental investigation of materials filled with dilatant fluid. In this field, the combination of X-ray flash system with instrumented dynamic experiments can reveal crucial aspects of their deformation behavior. The outputs of the project will provide an important insight into deformation behavior and will serve as an important basis for reliable numerical modeling of the related problems and for relevant optimization schemes during design process of state-of-the-art materials. The goal of the project is experimental investigation of state-of-the-art materials during impacts

2022 - 2026

JUNIOR STAR

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 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.; Ing. Tomáš Fíla, Ph.D.; Ing. Petr Koudelka, Ph.D.; Ing. Jan Šleichrt, Ph.D.

The project is focused on investigation of time-dependent processes influencing mechanical properties and internal structure of advanced engineering materials. Combination of analytical, numerical and experimental methods will be used for determination of relations between mechanical properties and microstructure of studied materials. In the theoretical part analytical and numerical methods will be implemented and techniques for evaluation of effective quasi-static and dynamic response of the studied materials will be developed. Experimental methods will involve enhancement of applications for processing and evaluation of experiments and also design of specialized measurement devices. These methods will be suitable for optimisation of the usage of advanced materials with microstructure in transportation applications and their safe operation.

2015 - 2017

Studentská grantová soutěž ČVUT - SGS15/225/OHK2/3T/16

Ing. Tomáš Doktor, Ph.D.; Ing. Tomáš Fíla, Ph.D.; Ing. Petr Koudelka, Ph.D.; doc. Ing. Bc. Zdeněk Padovec, Ph.D.; prof. Ing. Milan Růžička, CSc.

Konference 13th Youth Symposium on Experimental Solid Mechanics je setkáním mladých vědeckých pracovníků, doktorandů a studentů z evropských i mimoevropských univerzit a výzkumných center. Z ČVUT jsou registrováni účastníci z fakulty dopravní, strojní, stavební a jaderné a fyzikálně inženýrské. Jedná se o tradiční prezentaci prací především v oblasti experimentální mechaniky. Konkrétně se jedná o následující témata: - Pokročilé experimentální metody mechaniky kontinua a mechaniky tekutin - Nedestruktivní zkoušení - Lomová mechanika, poruchy materiálu - Biomechanika - Hybridní numericko-experimentální metody - Problematika technologických procesů - Mikro- a nano- aplikace Cílem konference je prezentace výsledků výzkumu, výměna zkušeností a navazování kontaktů. Výsledky jsou prezentovány formou komentovaných posterů doplněných vyzvanými přednáškami předních odborníků (letos K.H. Laermann, J. Lukeš). Na základě diskuze nad řešenými tématy vznikají návrhy na mezinárodní výzkumné projekty nebo stáže jednotlivých účastníků. Všechny příspěvky projdou před publikováním standardním peer-review procesem, pro nemalou část účastníků prvním v jejich publikační činnosti. Sborník plných textů bude zaslán k zařazení do databáze WoS. Autoři nejlepších příspěvků budou vyzváni k podání rozšířených verzí svých příspěvků do časopisu Measurement (IF 1.13).

2014 - 2014

Studentská vědecká konference ČVUT - SVK 49/14/F6

Ing. Tomáš Doktor, Ph.D.; Ing. Tomáš Fíla, Ph.D.; Ing. Petr Koudelka, Ph.D.; Ing. Jaroslav Valach, Ph.D.; Bc. Marek Žďárský

The aim of the project is focused on development of the methods for quantification of heterogeneous materials behaviour. This method will be used for determination of relations between mechanical and structural properties. The first goal is description of basic constitutive relations of advanced materials, the second goal is application on assessment of reactions to external loading. Preferably, nondestructive experimental methods and methods of image processing will be investigated. Investigation will be concentrated on observation of external environment influences on material microstructure. These methods will be useful for diagnostics and lifecycle predictions that are the key factor for transport systems safety.

2012 - 2014

Studentská grantová soutěž ČVUT - SGS12/205/OHK2/3T/16