Wyniki wyszukiwania - BazTech

1

Simulation method for measuring the impact energy of rail vehicles equipped with a soft absorber

Lisowska Aleksandra, Sanecki Henryk, Szkoda Maciej

Transport Problems

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2023

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T. 18, z. 3

15--28

EN

This paper presents a simulation method for testing the energy absorbed by the absorption systems of rail vehicles equipped with a soft absorber. The method makes it possible to verify the actual behavior of the absorption system during the impact of two vehicles. The first part of this paper describes the structural elements of a railway vehicle performing the function of an energy absorber during an impact according to the EN 15227 standard. A soft absorber, the so-called honeycomb, is analyzed in detail. It is a multicellular structure often used in rail vehicles due to its properties of controlled deformation. The literature review describes the research conducted on this element. The analytical part of this paper describes a general mathematical model of a rail vehicle collision according to Scenario 1, in which the collided vehicles are of the same type, and Scenario 2 for vehicles of different types. A computational impact simulation for the two scenarios has been carried out using the specialist software Mathcad, and the results are presented in graphs. The paper ends with conclusions presenting the application possibilities of the developed tool.

2

Numerical Study of the Energy Absorption Performance of 3D Printed Sandwich Structures

Estrada Quirino, Zubrzycki Jarosław, Reynoso-Jardón Elva, Szwedowicz Dariusz, Rodriguez-Mendez Alejandro, Marchewka Magdalena, Vergara-Vazquez Julio, Bastarrachea Aztlán, Silva Jesús M.

Advances in Science and Technology. Research Journal

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2023

|

Vol. 17, no 5

153--162

EN

Nowadays, Fused Deposition Modeling (FDM) is a powerful tool for manufacturing complex components, due to its customizability, low cost, accessibility, and fast prototyping time. It is an alternative for creating thin-walled structures, as it allows for novel designs. This article focuses on the design and numerical evaluation of 3D printed sandwich structures for energy absorption applications. For this purpose, five structures of Acrylonitrile Butadiene Styrene (ABS) were designed. To ensure optimal performance, the 3D printing parameters were optimized based on the corresponding literature. The structures had cores based on polygonal and cell arrangements. The effects of cross-section and mass on energy absorption were analyzed, and parameters such as energy absorption, peak load, mean force, and crush force efficiency (CFE) were determined during the study. The structures were assessed by out-of-plane compression tests. The numerical analysis was executed using Abaqus finite element software. Results showed that the energy absorption performance is primarily determined by the geometry and density of the structures. The best performance was found for a circular cellular structure, with a CFE of 0.884.

3

Wpływ koloru pokrycia na funkcjonowanie dachu

Patoka Krzysztof

Materiały Budowlane

|

2022

|

nr 11

214--215

4

Crashworthiness and comparative analysis of polygonal single and bi-tubular structures under axial loading – experiments and FE modelling

Kannan I. Vimal, Rajkumar R.

Journal of Theoretical and Applied Mechanics

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2021

|

Vol. 59 nr 1

81--94

EN

This article aims to present a report of experimental and numerical investigations on crashworthiness characteristics of single and multi-cell/bi-tubular structures. Novel multi--cell/bi-tubular structures are proposed in order to improve the crashworthiness performance, LS-DYNA FE software is applied for the modelling of axial crashing behaviour to validate with experimental results and a good agreement is observed. The KPIs are used to compare various structures and to determine the best performing ones. The investigations reveal that the HMC4 has significantly obvious effects on the structural crashworthiness and improved 515% energy absorption efficiency. Afterward, a parametric study has been carried out for the best energy absorber.

5

Structural Damage Characteristics of a Layer-to-Layer 3-D Angle-Interlock Woven Composite Subjected to Drop-Weight Impact

Qian Ma, Ke Wang, Shudong Wang, Yiwei Ouyang, Zhiqiang Lin, Wenfeng Shi, Limin Jin, Xianyan Wu

Autex Research Journal

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2021

|

Vol. 21, no. 3

293--298

EN

The most attractive structural feature of the three-dimensional (3D) angle-interlock woven structure is that the straight weft yarns are bundled by the undulated warp yarns, which induces the overall good structural stability and a stable fabric structure. Thus the 3-D angle-interlock woven composite (3DAWC) prepared by the vacuum-assisted resin transfer molding (VARTM) curing process has excellent mechanical properties by using the fabric and epoxy resin as the reinforcement and matrix, respectively. The low-velocity impact damage properties of the composites under different drop-weight energies (70, 80, and 100 J) were tested experimentally. The load–displacement curves, energy–time curves, and the ultimate failure modes were obtained to analyze the performance of resistance to low-velocity impact, as well as the impact energy absorption effect and failure mechanism, especially the structural damage characteristics of the 3DAWC subjected to the low-velocity impact of drop weight. By analyzing the obtained experimental results, it is found that the fabric reinforcement is the primary energy absorption component and the impact energy mainly propagates along the longitudinal direction of the yarns, especially the weft yarn system, which is arranged in a straight way. In addition, as the impact energy increases, the energy absorbed and dissipated by the composite increases simultaneously. This phenomenon is manifested in the severity of deformation and damage of the material, i.e., the amount of deformation and size of the damaged area.

6

Energy absorption of the strengthened viscoelastic multi-curved composite panel under friction force

Shao Yunhong, Zhao Yang, Gao Jun, Habibi Mostafa

Archives of Civil and Mechanical Engineering

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2021

|

Vol. 21, no. 4

71--99

EN

This study investigated FG carbon nanotubes filled composites, which are promising metamaterials that can be useful in the energy absorption field. This structure can absorb energy through elastic deformation. For this issue, absorbed energy and dynamic stability analysis of the FG-CNTRC curved panel surrounded by a non-polynomial viscoelastic substrate using three-dimensional poroelasticity theory is investigated. For stability of the structure after vibrating, the viscoelastic substrate as the non-polynomial viscoelastic model is presented. The curved panel comprises multilayer carbon nanotubes (CNT) which are uniformly distributed in all layers of facing sheets; however, the system’s weight fraction alters for each layer through the thickness orientation. The influences of several parameters, such as Winkler–Pasternak parameters, span angle CNTs’ volume fraction, length to radius ratio, compressibility coefficient, friction coefficient, torsional parameter, initial axial stress, and damping factor on the dynamic responses of the FG-CNTRC curved panel surrounded by a non-polynomial viscoelastic substrate are investigated. The golden result of this paper is that the effect of radial stress on the energy absorption is hardly dependent on the value of the foundation parameters. As an applicable outcome in pertained applications, by increasing the compressibility, and friction coefficients, the composite shell's energy absorption decreases.

7

Dynamic crushing behavior of closed-cell aluminum foams based on different space-filling unit cells

Talebi S., Hedayati R., Sadighi M.

Archives of Civil and Mechanical Engineering

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2021

|

Vol. 21, no. 3

231--245

EN

Closed-cell metal foams are cellular solids that show unique properties such as high strength to weight ratio, high energy absorption capacity, and low thermal conductivity. Due to being computation and cost effective, modeling the behavior of closed-cell foams using regular unit cells has attracted a lot of attention in this regard. Recent developments in additive manufacturing techniques which have made the production of rationally designed porous structures feasible has also contributed to recent increasing interest in studying the mechanical behavior of regular lattice structures. In this study, five different topologies namely Kelvin, Weaire–Phelan, rhombicuboctahedron, octahedral, and truncated cube are considered for constructing lattice structures. The effects of foam density and impact velocity on the stress–strain curves, first peak stress, and energy absorption capacity are investigated. The results showed that unit cell topology has a very significant effect on the stiffness, first peak stress, failure mode, and energy absorption capacity. Among all the unit cell types, the Kelvin unit cell demonstrated the most similar behavior to experimental test results. The Weaire–Phelan unit cell, while showing promising results in low and medium densities, demonstrated unstable behavior at high impact velocity. The lattice structures with high fractions of vertical walls (truncated cube and rhombicuboctahedron) showed higher stiffness and first peak stress values as compared to lattice structures with high ratio of oblique walls (Weaire–Phelan and Kelvin). However, as for the energy absorption capacity, other factors were important. The lattice structures with high cell wall surface area had higher energy absorption capacities as compared to lattice structures with low surface area. The results of this study are not only beneficial in determining the proper unit cell type in numerical modeling of dynamic behavior of closed-cell foams, but they are also advantageous in studying the dynamic behavior of additively manufactured lattice structures with different topologies.

8

Compressive Property of an Auxetic-Knitted Composite Tube Under Quasi-Static Loading

Boakye Andrews, Raji Rafui King, Ma Pibo, Cong Honglian

Autex Research Journal

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2020

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Vol. 20, no. 2

101--109

EN

This research investigates the compressive property of a novel composite based on a weft-knitted auxetic tube subjected to a quasi-static compression test. In order to maximize the influence of the fiber content on the compression test, a Kevlar yarn was used in knitting the tubular samples using three different auxetic arrow-head structures (i.e. 4 × 4, 6 × 6 and 8 × 8 structure). A quasi-static compression test was conducted under two different impact loading speeds (i.e. 5 mm/min and 15 mm/min loading speed). The results indicate that the energy absorption (EA) property of the auxetic composite is highly influenced by the auxeticity of the knitted tubular fabric.

9

Experimental and Numerical Studies of the Behavior and Energy Absorption of Foam-Filled Circular Tubes

Kaczyński P., Karliński J., Hawryluk M.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

521--527

EN

Following paper is focused on experimental and numerical studies of the behavior and energy absorption for both: quasi-static and dynamic axial crushing of thin-walled cylindrical tubes filled with foam. The experiments were conducted on single walled and double walled tubes. Unfilled profiles were compared with tubes filled with various density polyurethane foam. All experiments were done in order to possibility of the safety of the elements absorbing collision energy which can applied in car body. The dynamic nonlinear simulations were carried out by means of PAM-CRASH™ explicit code, which is dedicated calculation package to modelling of crush. Computational crushing force, plastic hinges locations and specimens post-crushed geometry found tobe convergent with the real experiments results. Conducted experiments allowed to draw conclusion, that crashworthiness ability is directly proportional to foam density. The investigation of the experimental data revealed, that double walled tubes have greater energy absorbing ability. A proposed investigation enable to analyze and chosen of optimal parameters of these elements, which can use in automotive industry as an absorption energy components.

10

Mechanical performances of metal-polymer sandwich structures with 3D-printed lattice cores subjected to bending load

Liu Zhaobing, Chen Hantang, Xing Shuaiqi

Archives of Civil and Mechanical Engineering

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2020

|

Vol. 20, no. 3

368--384

EN

In this article, we propose a new class of metal-polymer architected sandwich structures that exhibit different mechanical behaviors. These lightweight sandwich structures have been made of aluminum face sheets and 3D-printed lattice cores with 2D (Bi-grid, Tri-grid, Quadri-grid and Kagome-grid) and 3D (face-centered cubic-like and body-centered cubic-like) topologies. Finite element simulation and experimental tests were carried out to evaluate mechanical performances of the proposed sandwich structures under quasi-static three-point bending load. Specifically, the damage-tolerant capability, energy absorption and failure mechanisms of these sandwich structures were investigated and evaluated through a combination of analytical, numerical and experimental methods. It is found that sandwich structures with 3D face and body-centered cubic-like cores can provide more excellent flexural stiffness, strength and energy absorption performance. These enhanced mechanical features could be further explained by a so-called ‘Stress Propagation’ mechanism through finite element analysis (FEA) that can facilitate sandwich structures with 3D cores, especially body-centered cubic-like one, to transfer bending loads from central lattice units across neighboring ones more efficiently than 2D cores. Furthermore, core cracking is the main failure mode for the proposed sandwich structures, which is primarily caused and dominated by bending-induced tensile stress followed by shear stress. It is worth mentioning that our findings provide new insights into the design of novel lightweight sandwich composites with tailored mechanical properties, which can benefit a wide variety of high-performance applications.

11

Neural Networks in Crashworthiness Analysis of Thin-Walled Profile with Foam Filling

Rogala Michał

Advances in Science and Technology. Research Journal

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2020

|

Vol. 14, no 3

93--99

EN

This article presents the numerical tests of thin-walled compressed columns with a square cross-section. The crush efficiency indicators were determined using the finite element method (Abaqus) and neural networks of MLP. The models had a constant circular trigger, with a diameter of 32 mm. During dynamic analysis, the samples were loaded with 1700 J. The numerical models were filled with aluminum foam from 40 mm to 180 mm every 20 mm. The study presents the conclusions for the thin-walled models with crushable foam.

12

Effect of Test Velocity on the Specific Energy Absorption under Progressive Crushing of Composite Tubes

Ryzińska Grażyna, Gieleta Roman

Advances in Science and Technology. Research Journal

|

2020

|

Vol. 14, no 2

94--102

EN

The paper presents the results of the compression tests for carbon-epoxy composites in order to assess the amount of energy absorbed depending on the process velocity and content of axial fibres. Two types of prepreg (UD 200 g/m2 and woven 160 g/m2) were used to prepare the specimens with a diameter of 20 mm and a height of 34 mm. The specimens were subjected to compression under various speed conditions (static, dynamic and SHPB tests). The calculated specific energy absorption values showed a 50–60% decrease with increasing process velocity and depending on the type of specimens architecture. The highest energy values were absorbed by the specimens with the highest share of axial fibres in the sample.

13

Głowica do nanoszenia mieszanki elastomerowej na taśmę w linii technologicznej

Kozioł Stanisław, Matecki Krzysztof, Samborski Tomasz, Zbrowski Andrzej, Bąba Grzegorz

Technologia i Automatyzacja Montażu

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2019

|

nr 2

18--24

PL

W Instytucie Technologii Eksploatacji została zaprojektowana i wykonana prototypowa głowica dozująca elastomery termoplastyczne w specjalnie zaprojektowanej linii technologicznej, wytwarzającej kompozyty tkaninowo-elastomerowe. Głowica umożliwia dozowanie elastomeru na przemieszczający się materiał, wyrównywanie naniesionej warstwy lub tworzenie warstw nieciągłych - przepuszczalnych dla pary wodnej lub powietrza. W urządzeniu zastosowano ogrzewanie dozowanego medium za pomocą olejowego przewodu grzewczego lub elektrycznych elementów grzejnych z regulacją temperatury. Opracowana konstrukcja zapewnia możliwość zmiany kierunku przepływu podłoża w linii technologicznej, precyzyjną regulację grubości warstwy, automatyczną realizację ruchów ustawczych i serwisowych oraz bezpieczną obsługę. Firma BOCHEMIA, wykorzystując głowicę w zbudowanej w ramach realizowanego projektu linii technologicznej, opracowała innowacyjne rozwiązania w zakresie technologii wytwarzania wielofunkcyjnych kompozytów zawierających innowacyjne materiały wykazujące właściwości absorbujące energię, umożliwiające tłumienie uderzeń oraz właściwości wodoszczelne, grzybobójcze i bakteriobójcze.

EN

The prototype of a dispensing head of thermoplastic elastomers was designed and construct-ed at the Institute for Sustainable Technologies for a purpose-built manufacturing line for producing textile-elastomer composite glues. The elastomer dispensing head enables the transfer of the elastomer onto the moving material; it evens out the applied layer or creates discontinuous layers which are permeable for water vapour or air. The device heats the medium being dispensed using an oil heated conduit or electric heating elements with temperature control. This design is capable of changing the flow direction of the substrate in the manufacturing line, regulating a precise layer thickness, automatically executing setup and maintenance, and safe handling. Using the dispensing head constructed as part of project developing the manufacturing, the BOCHEMIA company has developed innovative solutions for manufacturing technologies of multifunctional composites of innovative materials which exhibit the following properties: energy absorbing (which provided impact absorption properties), fungicidal, and bactericidal.

14

Badania materiałów spodowych obuwia dla osób powyżej 60 lat

Czaplicki Zdzisław, Olejniczak Zbigniew, Serweta Wioleta

Przegląd Włókienniczy - Włókno, Odzież, Skóra

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2019

|

nr 5

30--32

PL

W artykule przedstawiono analizę porównawczą materiałów spodowych, z jakich wykonywane są spody obuwia dla osób 60+. Przy wyborze tych materiałów uwzględniono ich dostępność na rynku oraz wykorzystywanie przez producentów obuwia. Badano pięć różnych materiałów podeszwowych wykonanych na bazie polichlorku winylu, kauczuku termoplastycznego i poliuretanu. W badanych próbkach określono m. in. takie parametry jak odporność na ścieranie, twardość, elastyczność, absorpcję energii i współczynnik tarcia (odporność na poślizg). Stwierdzono, że najlepsze wyniki uzyskały próbki wykonane na bazie polichlorku winylu.

EN

This paper presents the comparative analysis of the sole materials for the shoes sole used by the persons over 60th+. The choice of materials was considered their accesability on the market and application by the shoes manufactures. Five different sole materials manufactured on the basis of polyvinyl chloride (PVC), thermoplastic rubber and polyurethane were investigated. During the investigations the following parameters were determined: resistance to abrasion, hardness, elasticity, energy absorption and friction coefficient (resistance for slide). It was stated that the best results were obtained the specimens produced on the basis of polyurethane.

15

Research on energy absorption properties of open-cell copper foam for current collector of Li-ions

Chen Jian, Li Xiongfei, Li Wei, Li Cong, Xie Baoshan, Dai Shuowei, He Jian-Jun, Ren Yanjie

Materials Science Poland

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2019

|

Vol. 37, No. 1

8--15

EN

Quasi-static uniaxial compressive tests of open-cell copper (Cu) foams (OCCF) were carried out on an in-situ bi-direction tension/compress testing machine (IBTC 2000). The effects of strain rate, porosity and pore size on the energy absorption of open-cell copper foams were investigated to reveal the energy absorption mechanism. The results show that three performance parameters of open-cell copper foams (OCCF), involving compressive strength, Young modulus and yield stress, increase simultaneously with an increase of strain rate and reduce with increasing porosity and pore size. Furthermore, the energy absorption capacity of OCCF increases with an increase of porosity and pore size. However, energy absorption efficiency increases with increasing porosity and decreasing pore size. The finite element simulation results show that the two-dimensional stochastic model can predict the energy absorption performance of the foam during the compressive process. The large permanent plastic deformation at the weak edge hole is the main factor that affects the energy absorption.

16

Sposoby redukcji efektu miejskiej wyspy ciepła

Kleszczewska Katarzyna

Inżynieria i Budownictwo

|

2019

|

R. 75, nr 3

116--118

PL

Omówiono przyczyny powstawania i wpływ miejskich wysp ciepła oraz strategie zmierzające do redukcji temperatury w skupiskach ludności. Skupiono się przede wszystkim na technologiach związanych z nawierzchnią, zmierzających do zmniejszenia magazynowania przez nie ciepła i obniżenia temperatury powierzchni.

EN

The paper describes the causes and impact of urban heat islands and promotes strategies for lowering temperatures in population concentration. Main focus is concentrated on pavement technologies tend to store less heat and may have lower surface temperatures.

17

A parametric study of the mechanical behavior of nested multi tube structures under quasi-static loading

Chahardoli S., Alavi Nia A., Asadi Mehrdad

Archives of Civil and Mechanical Engineering

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2019

|

Vol. 19, no. 4

943--957

EN

Mechanical behavior of nested aluminum structures under lateral and quasi-static loadings has been investigated in current paper. These structures consist of two nested tubes in which the inner tube is located vertically in the horizontal outer tube. The research has been done numerically and experimentally. In the numerical section, the LS-DYNA software has been used while experimental results are implemented to validate the FE outcome. The well correlated numerical results show that increasing the diameter of the inner tube leads to a decrease in the maximum force and the specific energy absorption. Later, employing the optimization by response surface method in Minitab software, the energy absorber's characteristics has been optimized and introduced as new set of specifications. High crush force efficiency is the main criterion in current research.

18

Numerical Crush Analysis of Thin-Walled Aluminium Columns with Square Cross-Section and a Partial Foam Filling

Ferdynus Mirosław, Rogala Michał

Advances in Science and Technology. Research Journal

|

2019

|

Vol. 13, no 3

144--151

EN

The article presents the results of numerical crush simulations of thin-walled structures with a square cross-section and partial filling with foamed material. The influence of the length of the filling on the values of the energy efficiency index was analysed. Four types of foamed material were subjected to numerical analysis. The research was conducted using FEM in Abaqus 6.14 program. The obtained results were presented in the following forms: load-shortening characteristics, tables and diagrams. The best energy absorbing properties are shown by models filled with aluminium and polyethylene terephthalate foam.

19

Rdzenie konstrukcji kompozytowych z pianek półsztywnych do zastosowań w tarczach ochronnych dla strażaków

Ryszkowska J., Leszczyńska M., Auguścik M., Bryśkiewicz A., Półka M., Kukfisz B., Wierzbicki Ł., Aleksandrowicz J., Szczepkowski L., Oliwa R.

Polimery

|

2018

|

T. 63, nr 2

125—133

PL

Przedmiotem badań były półsztywne pianki poliuretanowe zaliczane do grupy materiałów absorbujących energię, zastosowane do wytwarzania elementów konstrukcji tarcz ochronnych dla strażaków. W celu zwiększenia odporności pianek na działanie ognia modyfikowano je dodatkiem grafitu ekspandującego i Fyrol PNX. Otrzymano pianki trudnopalne, o zmniejszonej zapalności i ograniczonej ilości wydzielanego dymu, wykazujące zdolność do pochłaniania 12–19 % energii uderzenia. Wprowadzenie do wytwarzanej kompozycji piankowej odpadu gumowego pozwoliło na obniżenie ceny pianek o ok. 25 %.

EN

The subject of the paper are semi-rigid polyurethane foams. They belong to a group of energy-absorbing materials, which have been used for manufacture of structural components of protecting shields for firefighters. In order to increase the fire resistance of the foams they were modified by addition of expandable graphite and Fyrol PNX. As a result, flame retardant foams have been obtained, with reduced flammability and limited amount of smoke emission, having an ability to absorb impact energy in the amount of 12–19 %. By introducing a rubber waste during the manufacture of foam composition, the price of foams was reduced by about 25 %.

20

Ocena jakościowa procesu deformacji regularnych struktur komórkowych wykonanych techniką druku 3D

Dziewit P., Janiszewski J.

Mechanik

|

2018

|

R. 91, nr 3

250--252

PL

Przedstawiono wybrane wyniki badań eksperymentalnych, umożliwiające przeanalizowanie procesu deformacji regularnych struktur komórkowych wykonanych techniką druku 3D w warunkach obciążenia quasi-statycznego. Zaprojektowane w środowisku CAD warianty topologii struktur wykonano metodą FDM (fused deposition modeling), a następnie poddano je badaniom w warunkach jednoosiowego testu na ściskanie. Punktem wyjścia do opracowania poszczególnych wariantów struktur była topologia plastra miodu. Aby przeanalizować wpływ materiału struktury na przebieg procesu deformacji, próbki wykonano z trzech komercyjnie dostępnych materiałów: PC-10, ABSplus i Nylon12. Na podstawie wyników badań oceniono wpływ kształtu komórki elementarnej oraz rodzaju zastosowanego materiału na przebieg deformacji struktury i wartość energii odkształcenia plastycznego.

EN

Presented are selected experimental results concerning the analysis of the deformation process of regular cellular structures manufactured using 3D printing under quasi-static loading conditions. The various structural topologies were designed and manufactured using the FDM (fused deposition modelling) and then tested in a uniaxial compression test. The starting point for the development of individual variants of structures was the honeycomb topology. In order to analyse the influence of the structure material on the deformation process, the samples were made from three commercially available materials: PC-10, ABSplus and Nylon12. Based on the results, the influence of the shape of the single cell and the type of material used on the deformation of the structure as well as the value of the plastic deformation energy were assessed.