People
doc. Ing. Petr Zlámal, Ph.D.

doc. Ing. Petr Zlámal, Ph.D.

At present, there is a notable absence of research dedicated to the examination of the mechanical properties of additively manufactured materials that have been filled with non-Newtonian liquids (NNLs). This is despite the fact that this area of study holds considerable promise for a range of practical applications. It is for this reason that the proposed project is focused on the research and development of these materials, with an emphasis on investigating the mechanical behaviour of NFCs. NNLs are fluids whose viscosity is not constant and depends on the strain rate. Amongst the most important types of NNLs are shear-thickening fluids (STFs) and shear-thinning fluids. These fluids, in the form of fillers for various components, have promising prospects for future use, including in the transport industry for the manufacture of shock absorbers for cars, aircraft or protective equipment for motorcyclists and cyclists, and in the construction industry for the dampening of vibrations and the protection of buildings from damage. The project will concentrate on the preparation of NNLs that are suitable for use with 3D-printed materials and the design of these printed structures for experimental testing. The objective of the tests is to characterise the mechanical properties, particularly at medium and high strain rates, with an emphasis on investigating the interaction between the base material and the filler layers. The research will be conducted using the advanced experimental equipment of the DynLab laboratory of the Czech Technical University in Prague, Faculty of Transport (CTU FD), including equipment for the preparation of NNLs, gas-gun for dynamic impact simulation, split Hopkinson pressure bar (SHPB) for the analysis of the material response to rapid deformation conditions, and dynamic testing equipment based on linear motors. Furthermore, the interaction between the base material and the fluid will be analysed using X-ray imaging systems in addition to standa

2025 - 2026

Studentská grantová soutěž ČVUT - SGS25/102/OHK2/2T/16

doc. Ing. Petr Zlámal, Ph.D.

The present project deals with testing and investigation of multimaterial samples created by 3D printing. Such structures have a wide range of applications as a wide range of elements can be worked with and combined within the design to create the desired properties. The created component can be used as a frequency filter, a component with variable mechanical, thermal and electrical properties or the created structure, can seduce mechanical waves to a specific location where a piezoelectric member can be placed and used for Energy Harvesting. In these applications, the multimaterial is subjected to different types and rates of mechanical deformation. The material can be stressed non-destructively by wave propagation at different frequencies, or destructively at different strain rates and under cyclic loading. The behaviour of these structures is not well described for the above mentioned mechanical stresses. The proposed project will address the development of a methodology for non-destructive and destructive testing at high strain rates on a Hopkinson split pressure bar (SHPB) and at medium and low strain rates on an experimental setup using linear induction motors (LIMA). The objective of the experimental testing will be to determine the strain and wave characteristics of the multimaterial structures in question. Thanks to the possibility of using advanced experimental equipment (fast X-ray imaging, precision cyclic loading, electron microscopy), it will also be possible to investigate the influence of the quality of the interface between the sub-materials. The quality of the interface has a key influence on the behaviour of the overall multi-material structure, both in terms of deformation behaviour and stress wave propagation.

2025 - 2026

Studentská grantová soutěž ČVUT - SGS25/103/OHK2/2T/16

Ing. et Ing. Radim Dvořák; doc. Ing. Petr Zlámal, Ph.D.

Project is aimed at precise simulations for training of physics-informed machine learning schemes in optimization of materials with respect to deformation energy mitigation. Advanced finite element simulations methods with state-of-the-art techniques of dynamic testing are combined for investigation of intermediate and high strain rate impact response of materials with complex internal structure in relation to machine learning applications. The investigated materials are additively manufactured structures, including auxetic lattices, and inter-penetrating composites. Experimental methods involve flash and high-speed X-ray radiography togetherwith high speed visible-light and infrared cameras. The numerical methods using finite element methods with explicit time integration will enable physically accurate simulations of loading scenarios and in-house solver for unprecedented insight into wave propagation in materials during impact will be developed. Moreover, simulations of radiographical methods will allow tosimulate all aspects of experiments.

2025 - 2027

Standard projects

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. 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

Ing. Tomáš Doktor, Ph.D.; Ing. Jan Falta; Ing. Michaela Jurko

Konference 17th Youth Symposium on Experimental Solid Mechanics (YSESM2019) navazuje na předchozí pravidelné setkávání mladých vědeckých pracovníků, doktorandů a studentů z oblasti především experimentální mechaniky. Organizace konference po pěti letech opět připadla české straně. Vzhledem k dlouhé tradici konference (17. ročník) a poměrně velkému počtu zúčastněných institucí ze zemí střední Evropy se pro ČVUT jedná o akci prestižní a významnou především s ohledem na utváření mezinarodních vazeb mezi začínajícími výzkumníky. Konference je spolupořádána Ústavem teoretické a aplikované mechaniky AV ČR a časově i místem konáni navazuje na High-Resolution 3D X-ray Imaging Workshop, na který budou mít registrovaní účastníci YSESM volný přístup. Program konference je koncipován tak, aby nebylo nutné organizovat paralelní sekce. Účastníci přednesou své krátké (10 min) ústní referáty, které budou po skončení příslušné sekce následovány diskuzí u posterů. Tento koncept se v minulých ročnících osvědčil a dopomohl vzniku či dalšímu rozvoji spolupráce mezi jednotlivými účastníky a jejich domovskými institucemi. Publikačním výstupem konference bude sborník jednostránkových abstraktů, který bude k dispozici před zahájením konference a především pak samostatné číslo Acta Polytechnica CTU Proceedings (indexované WoS) kde budou publikovány plné texty příspěvků. Všechny příspěvky projdou před publikováním standardním peer-review procesem, pro nemalou část účastníků prvním v jejich publikační činnosti. Tematické zaměření konference zahrnuje zejména - Pokročilé experimentální metody mechaniky kontinua a mechaniky tekutin - Nedestruktivní zkoušení - Lomová mechanika, poruchy materiálu - Biomechanika - Hybridní numericko-experimentální metody - Problematika technologických procesů - Aditivní výroba

2019 - 2019

Studentská vědecká konference ČVUT - SVK 44/19/F6

doc. Ing. Michal Micka, CSc.

Understanding of the inner structure of materials and their main components is an essential requirement for a correct description of the mechanical behavior of structurally complex materials during the loading. Grant focuses on the application and development of experimental methods and computer algorithms in the detection, description and modeling of the behaviour of the samples, mostly porous material (trabecular bone, metal foam), both at the micro level (e.g. trabecula) and the whole sample level (e.g. tissue). Development of experimental techniques for exact determination of the deformation field on the sample's surface or in the sample's volume together with advanced algorithms for exact assessment of the deformation tensor from a single experiment. The project will use existing test devices, but simple modification or supplement of experimental setup will be necessary.

2011 - 2012

Studentská grantová soutěž ČVUT - SGS11/140/OHK2/2T/16