Wyniki wyszukiwania - BazTech

1

Research on the design and simulation of frontal collision assessment of a truck with emergency vehicle suppression system

Vu Hai Quan, Tran Quang Tam, Nguyen Anh Ngoc, Le Hong Quan, Hoang Khai Hung

Zeszyty Naukowe. Transport / Politechnika Śląska

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2025

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z. 128

295--309

EN

In response to the growing threat of vehicle-ramming attacks targeting critical infrastructure such as airports, government facilities, and public gathering spaces, this study focuses on the design and simulation of a direct frontal collision between a heavy truck and an emergency vehicle barrier using the Finite Element Method (FEM). The simulation model is developed to replicate realistic impact conditions, allowing detailed analysis of the barrier’s structural behavior under extreme loads, including deformation patterns, stress distribution, and energy absorption capacity. Material properties, contact interactions, and boundary constraints are carefully defined to enhance simulation accuracy. The results reveal that an optimally designed barrier with reinforced structures and effective energy-dissipating features can significantly reduce damage and vehicle intrusion, thereby improving overall protective performance. This confirms the crucial role of FEM-based simulation in the early design phase of physical security systems, offering a cost-effective and predictive approach to evaluating and optimizing barrier effectiveness before real-world deployment.

2

Mechanical energy absorption capacity of the porous Ti-6AI-4V alloy under quasi-static and dynamic compression

Markovsky Pavlo E., Janiszewski Jacek, Stasiuk Oleksandr O., Savvakin Dymitro G., Oryshych Denys V., Dziewit Piotr

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2025

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Vol. 73, nr 1

art. no. e151959

EN

Porous materials are extremely efficient in absorbing mechanical energy in different applications. In the present study, porous materials based on the Ti-6(wt.%)Al-4V alloy were manufactured with the use of two different powder metallurgy methods: i) blended elemental powder approach using titanium hydride (TiH2) as well as V-Al master alloy powders and ii) using hydrogenated Ti-6-4 pre-alloyed powder. The powder compacts were sintered with additions of ammonium bicarbonate as a pore-holding removable agent. The emission of hydrogen from hydrogenated powders on vacuum sintering and the resulting shrinkage of powder particles permitted the control of the sintering process and the creation of anticipated porous structures. Mechanical characteristics were evaluated under quasi-static and dynamic compressive loading conditions. Dynamic compression tests were performed using the direct impact Hopkinson pressure bar technique. All investigations aimed at characterizing the mechanical energy-absorbing ability of the obtained porous structures. The anticipated strength, plasticity, and energyabsorbing characteristics of porous Ti-6-4 material were evaluated, and the possibilities of their application were also discussed. Based on the obtained results, it was found that porous Ti-6-4 material produced with a blended elemental powder approach showed more promising energy absorption properties in comparison with pre-alloyed powder.

3

Comparative analysis of the use of classic and light materials in the construction of energy-absorbing structures in vehicles

Dombrowski Patryk, Okruch Łukasz, Jasiński Paweł

Archiwum Motoryzacji

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2025

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Vol. 109, nr 3

23--40

EN

This study investigates the performance of steel and aluminum alloys in the construction of energy-absorbing elements used in front collision management systems, essential for enhancing vehicle safety during frontal impacts. These systems are designed to absorb and dissipate impact energy while minimizing the acceleration forces transmitted to vehicle occupants, which could lead to injury. The research evaluates the impact of material choice and geometric modifications on the performance of these absorbers, using FEM. Steel absorbers, known for their high strength, effectively absorb energy through plastic deformation while maintaining structural integrity. On the other hand, aluminum absorbers, with their lower density, offer notable advantages in reducing the overall mass of the vehicle, thus improving fuel efficiency and performance. However, a comprehensive analysis of the current state of knowledge on these materials in energy absorption applications is necessary. Previous studies, such as those by Bhardawaj et al.[201] and Hussain et al. [192], have explored similar aspects using simulation techniques, providing a foundation for further development in this field. Additionally, material properties and their impact on structural performance have been examined, offering insights into lightweight design optimization [3]. This study also explores two geometric modifications—perforations and indentations—designed to optimize the absorber's acceleration profile and enhance energy dissipation. While these modifications have been analyzed in prior research, their combined impact with material selection in crash absorbers remains insufficiently examined. Therefore, this work builds on existing findings to further investigate the effectiveness of these geometric features, integrating insights from recent studies. The results provide valuable insights into how material selection and geometric optimization can be combined to lightweight and high-performing energy-absorbing elements in collision management systems. Additionally, this study highlights gaps in the literature and suggests future directions for optimizing energy dissipation in crash absorbers, ensuring a well-grounded contribution to the state of knowledge.

4

Exploring the potential: auxetic metamaterials as core elements in buckling restrained braces

Basri Hamza, Ras Abdelouahab, Hamdaoui Karim, Wielgos Piotr

Archives of Civil Engineering

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2025

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Vol. 71, nr 3

325--338

EN

Buckling restrained braces (BRBs) are now widely used in different seismic zones as lateral resisting systems due to their quasi-symmetric and stable cyclic behavior. These systems are capable of dissipating the energy of severe lateral loads while protecting the integrity of other components of the structure. The material selection for these damper components as the inner core element requires high ductility, low strength increase, and high energy dissipation ability. Therefore, designing BRB steel cores using auxetic metamaterials has been recently investigated and suggested in the field of structure protection. The behavior of these metamaterials is characterized by a negative Poisson’s ratio (NPR) and unique mechanical characteristics, including their shear resistance and high ability for energy absorption. In this paper, we seek to investigate the effect of auxetic behavior on the dissipative performance of BRB under cyclic loading. Two different types of BRB were numerically designed and modeled using the finite element program Abaqus. The numerical analysis results show stable hysteresis behavior in both specimens and good stress distribution along the inner auxetic core. In addition, a parametric study was conducted to further investigate the effect of the gap size between the auxetic core and the concrete encasement. The cyclic performance of a buckling restrained brace with an auxetic perforated core was assessed, and the outcomes of this numerical analysis provide a reasonable basis for applying an auxetic core in the field of structure protection.

PL

Stężenia z ograniczonym wyboczeniem (Buckling Restrained Braces BRB) są obecnie szeroko stosowane w różnych strefach sejsmicznych jako boczne systemy nośne ze względu na ich quasisymetryczne i stabilne zachowanie cykliczne. Systemy te są w stanie rozproszyć energię dużych obciążeń poprzecznych, chroniąc jednocześnie integralność innych elementów konstrukcji. Wybór materiału na te elementy tłumika jako element rdzenia wewnętrznego wymaga wysokiej ciągliwości, niskiego wzrostu wytrzymałości i dużej zdolności rozpraszania energii. Dlatego też w ostatnim czasie badano i sugerowano projektowanie rdzeni stalowych BRB z wykorzystaniem metamateriałów auksetycznych w dziedzinie ochrony konstrukcji. Zachowanie tych metamateriałów charakteryzuje się ujemnym współczynnikiem Poissona (negative Poisson’s ratio NPR) i unikalnymi właściwościami mechanicznymi, w tym odpornością na ścinanie i dużą zdolnością do pochłaniania energii. W tym artykule staramy się zbadać wpływ zachowania rdzenia auksetycznego na wydajność rozpraszającą BRB pod obciążeniem cyklicznym. Zaprojektowano numerycznie i zamodelowano dwa różne typy BRB przy użyciu programu elementów skończonych Abaqus.Wyniki analizy numerycznej wskazują na stabilne zachowanie histerezy w obu próbkach i dobry rozkład naprężeń wzdłuż wewnętrznego rdzenia auksetycznego. Ponadto przeprowadzono badanie parametryczne w celu dalszego zbadania wpływu rozmiaru szczeliny pomiędzy rdzeniem auksetycznym a obudową betonową. Oceniono cykliczną wydajność stężenia z ograniczonym wyboczeniem z auksetycznym perforowanym rdzeniem, a wyniki tej analizy numerycznej stanowią uzasadnioną podstawę do zastosowania rdzenia auksetycznego w dziedzinie ochrony konstrukcji.

5

Numerical studies of the energy absorption capacities and deformation mechanisms of 2D cellular topologies

Majdak Mateusz, Baranowski Paweł, Małachowski Jerzy

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e111, 2024

EN

This paper investigates the energy absorption capacities of selected cellular topologies under quasi-static loading conditions. Twenty topologies with nearly identical relative densities belonging to 4 groups were examined: honeycomb, re-entrant, bioinspired and chiral. The topologies were modeled using an experimentally validated numerical ABSplus model and subsequently subjected to in-plane uniaxial compression tests. The findings revealed the topologies with the most favorable energy absorption parameters and the main deformation mechanisms. The topologies were classified by mechanism, and a parametric study of basic material properties, namely modulus of elasticity, yield stress, and ductility, was performed for a representative topology from each mechanism. The results indicated that the honeycomb group topologies were characterized by the largest average absorbed energy, and yield stress was found to have the greatest impact on energy absorption efficiency regardless of the main deformation mechanism.

6

Numerical simulation on progressive failure of yielding support material for squeezing tunnel

Ci Xiang, Liu Xinyu, Tan Xianjun, Yang Diansen, Tian Hongming, Chen Weizhong

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 1

art. no. e9, 2024

EN

Yielding support is effective in controlling excessive deformation of soft rock in squeezing tunnel engineering, and the developed polyethylene (PE) pipe filled with foamed concrete is a good choice serving as a yielding support. To deal with distortions brought on by significant mesh deformations and to enhance visualization, a numerical simulation method based on finite element method-smoothed particle hydrodynamics coupling (FEM-SPH) is adopted taking into account the progressive failure of PE pipes filled with foamed concrete (FC-PE) during deformation. By simulating the gradual failure of foamed concrete through smooth particle flow and the wrapped PE pipe using the finite element method, the damage process of the filled pipe has been examined. Comparison with experimental results demonstrates the superiority of the proposed model in terms of computational efficiency and accuracy, investigating the impact of several critical variables on the energy absorption capabilities of FC-PE, as well as setting pertinent evaluation indicators based on practical engineering application conditions. Additionally, numerical results demonstrate that the frictional characteristics between PE pipe and foamed concrete have little effects on the deformation energy absorption properties. The numerical results also demonstrate that the FC-PE’s diameter has a positive impact on both the energy absorption efficiency and the usage efficiency, while thicker FC-PE having a lower energy absorption efficiency.

7

Energy absorption analysis under in‑plane impact of hexachiral honeycomb with different arrangements

Cai Zhenzhen, Deng Xiaolin, Wang Guangxiang

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e77, 2024

EN

This study explores the design and performance of axisymmetric hexachiral honeycombs, utilizing the hexachiral honeycomb framework and axisymmetric design method. Four axisymmetric hexachiral honeycombs with distinct arrangements were developed: left-right symmetry hexachiral honeycomb (LSHH), up-down symmetry hexachiral honeycomb (USHH), central symmetry hexachiral honeycomb (CSHH), and subunits symmetry hexachiral honeycomb (SSHH). The deformation patterns and compression behaviors of these honeycombs were comprehensively examined through experimental and numerical simulations, and comparisons were made with a non-symmetric hexachiral honeycomb (NHH). The results indicate that symmetrically designed honeycombs exhibit a larger mean plateau stress than the asymmetrically designed the NHH during low-velocity impacts. The study further discusses deformation patterns, specific energy absorption, and the negative Poisson's ratio effect across the five honeycombs under different parameters. Notably, symmetrically designed honeycombs demonstrate superior specific energy absorption, and the negative Poisson's ratio effect becomes evident at an impact velocity of 10 m/s. However, the advantages of axisymmetric honeycombs diminish at higher impact velocities of 50 m/s and 100 m/s. The Poisson's ratio effects of symmetric honeycombs weaken with an increase in the circular ligament r of the honeycomb. Additionally, the study identifies that platform stress and SEA increase for honeycombs with horizontal cell numbers greater than 6.

8

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.

9

Energy absorption, free and forced vibrations of flexoelectric nanocomposite magnetostrictive sandwich nanoplates with single sinusoidal edge on the frictional torsional viscoelastic medium

Chu C., Shan L., Al‑Furjan M. S. H., Farrokhian A., Kolahchi R.

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 4

art. e223, 1--28

EN

Most studies on the nanoscale mainly focus on regular rectangular nanoplates, but according to the synthesis of nanostructures, the dynamic response of non-rectangular nanoplates is noticeable and there are not many works on these complex nanostructures. This work presents energy absorption, and forced and free vibrations of sandwich non-rectangular nanoplates with a single sinusoidal edge resting on a fractional torsional viscoelastic medium. The nanostructure is made from alumina reinforced by graphene platelets (GPLs) as a core covered by the flexoelectric and magnetostrictive materials as top and bottom layers, respectively. The consideration of size effects is derived from the innovative theory of local/nonlocal phenomena in a two-phase context. The Halpin-Tsai micromechanical and Kelvin–Voigt models are applied for the effective characteristics of the material in the nanocomposite layer and structural damping, respectively. Based on Hamilton’s principle and refined zigzag theory (RZT), the coupled electro-magneto-mechanical equations of motion are gained and analyzed by Galerkin’s and Newmark’s procedures. The effects of different components, including factors related to both the nonlocal and local phase fractions, the volume fraction of GPLs, various elastic mediums, electric field, structural damping, magnetic field, piezoelectric and flexoelectric effects on the absorption of energy, and forced and free vibrations of the sandwich nanostructure. Numerical simulations demonstrate that optimal energy absorption occurs when the flexoelectric factor is set to zero and the piezoelectric constant is non-zero but of opposite polarity. Additionally, it is concluded that when the coefficient of the local phase fraction is zero, increasing the nonlocal factor has more influence on the energy absorption and vibration of the nanostructure.

10

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.

11

Wpływ koloru pokrycia na funkcjonowanie dachu

Patoka Krzysztof

Materiały Budowlane

|

2022

|

nr 11

214--215

12

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

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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.

13

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

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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.

14

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.

15

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

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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.

16

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.

17

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

|

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.

18

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

|

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.

19

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

Rogala Michał

Advances in Science and Technology. Research Journal

|

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.

20

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.