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1

Optimizing Fused Deposition Modelling Process Parameters for Medical Grade Polymethylmethacrylate Flexural Strength

Obaeed Nareen Hafidh, Hamdan Wisam K.

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

349--359

EN

The production of functional parts, including those employed by the biomedical industry has been achieved a promising candidate in Fused Deposition Modelling (FDM). The essential properties of these biomedical parts which manufactured by additive manufacturing as compared to some other conventional manufacturing processes depend on structural and process parameters rather than material properties alone. Regarding to the evaluation the flexural strength of medical-grade, Polymethylmethacrylate PMMA has been received relatively very little investigation to date. PMMA is a biocompatible filament that be used in manufacturing of patient-specific implants such as dental prosthesis and orthopaedic implants. The proposed work explores the effect of three process parameters that vary with respect of three levels on the flexural strength. These levels can be specified by layer height (120, 200, 280 µm), infill density (40, 65, 90 %) and skewing angle (0º, 45º, 90º) on the flexural strength of medical-grade PMMA. Maximum and minimum flexural strength that be obtained in this work about (93 and 57 MPa) respectively. The analysis of variance (ANOVA) results shows that the most effective factor is the layer height followed by infill density. The flexural strength rises significantly with decreases layer height and the skewing angle is in zero direction. The process parameters have been optimized through utilizing of genetic algorithms. The optimal results that emerged based on genetic algorithm technique are approximately (276 μm) as layer height, (46 %) infill density and skewing angle (89 º) which maximize the flexural strength to (97 MPa) at crossover for ten generation.

2

Three-point bending of a beam with non-homogeneous structure in the depth direction

Magnucki Krzysztof, Magnucka-Blandzi Ewa, Witkowski Dawid, Wittenbeck Leszek

Engineering Transactions

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2023

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Vol. 71, iss. 4

645--665

EN

This paper is devoted to the behavior of a non-homogeneous simply supported beam under three-point bending. The individual shear deformation function of a planar cross-section is adopted, and longitudinal displacements, strains, and stresses for two parts of the beam are explained. By applying the principle of stationary potential energy, a system of two differential equations of equilibrium is derived and solved analytically. The positions of the neutral axis, shear coefficients, and deflections are then calculated for three different beam families. Additionally, the bending problem of these beams is studied numerically using the finite element method (FEM). The results of both analytical and numerical calculations are presented in tables and figures. The main contribution of this paper lies in the development of an analytical model incorporating the individual shear deformation function and a numerical FEM model for this beam.

3

Evaluation of Surface Preparation Technology for Steel Components with Fluoropolymer-based Coatings in Terms of Anti-adhesive and Mechanical Properties

Miturska-Barańska Izabela, Doluk Elżbieta

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

140--154

EN

The subject of the research presented in this paper was the evaluation of the technology of surface preparation of steel samples in terms of anti-adhesion and mechanical properties through the use of PFA coatings. Such coatings are used in many industries, e.g. in the manufacture and operation of metal moulds used, for example, in the production of resinous components. The specimens used in the study, which represented the surface of the moulds, were made from DC01 sheet. Six variants of release coating technology were used, differing in the number of technological operations and parameters. In the final stage, appropriate test methods were used to assess the energy properties of the coatings produced, the mechanical properties in terms of deformation of the supporting structure and the mechanical properties in terms of the effects on the coating itself. The scope of the research made it possible to determine the main properties that the manufactured coatings have in terms of their future practical applications. The results obtained for the surface free energy determined from the measurement of the surface wetting angle, the mechanical properties obtained from the three-point bending test and the evaluation of the surface quality of the coatings subjected to compressive and tensile deformations in the bending test, as well as the functional properties of the coatings in terms of their durability and adhesion determined in scratch tests, showed that the best characteristics were obtained for variant 6. This variant consisted of sequentially, after the initial stage, applying a primer layer and drying it for 15 minutes at 250°C, applying a PFA layer to the component at 150°C and then drying it for 15 minutes at 200°C and curing it for 20 minutes at 380°C. An additional layer of PFA was then applied and dried for 15 minutes at 200°C and cured for 20 minutes at 340°C. In addition, a long annealing for 3 hours at 340°C was applied in a given variant.

4

Failure analysis of beam composite elements subjected to three-point bending using advanced numerical damage models

Różyło Patryk

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 1

133-144

EN

This paper deals with the experimental and numerical analysis of three-point bending phenomenon on beam composite profiles. Flat rectangular test specimens made of carbon–epoxy composite, characterised by symmetric [0/90/0/90]s laminate ply lay-up, were used in this study. Experimental testing was carried out with a COMETECH universal testing machine, using special three-point bending heads. In addition, macroscopic evaluation was performed experimentally using a KEYENCE Digital Microscope with a mobile head recording real-time images. Parallel to the experimental studies, numerical simulations were performed using the finite element method in ABAQUS software. The application of the above-mentioned interdisciplinary research techniques allowed for a thorough analysis of the phenomenon of failure of the composite material subjected to bending. The obtained research results provided a better understanding of the failure mechanism of the composite material.

5

Fillet effect on the bending crashworthiness of thin-walled square tubes

Xie Zhongyou, Zhao Zhixian, Zhou Xiuneng, Li Cheng

Journal of Theoretical and Applied Mechanics

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2022

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Vol. 60 nr 1

103--111

EN

Filleting four corners of square tubes is suggested to reduce the peak force and improve energy absorbing performance. Three-point bending tests are conducted to investigate fillet radius effects employing an ABAQUS explicit code. Three cases characterized by the ratio of width to thickness are considered. Fillet greatly reduces the maximum forces compared with square cross-sections, and the normalized maximum forces decrease with increasing wall thickness when the fillet radius is larger. Additionally, the fillet dramatically improves SEA (Specific Energy Absorption). The normalized CFE (Crash Load Efficiency) significantly exceeds that of the square ones, and the normalized CLEs are almost identical with the increasing fillet radius.

6

Comparison of the Bending Resistance Properties of Carbon Fiber/Foam Sandwich Structural Composites with Different Laying Angles

Zhu Lvtao, Cao Shengbin, Zhang Xiaofeng, Shen Wei, Zhu Chengyan

Fibres & Textiles in Eastern Europe

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2022

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Vol. 30, no. 2

75--81

EN

This research aimed to explore the influence of fiber laying angles on the bending resistance properties of carbon fiber/foam sandwich structural composites. Four kinds of composites with the following laying angles: [0°]8, [0°/45°/90°/-45°]s, [0°/90°]4 and [45°/-45°]4 were prepared and tested in three-point bending experiments. The results obtained showed that the bending resistance performance was the best when the laying angle was [0°]8, while it was the worst when the laying angle was [45°/-45°]4. Besides, it was found that the tensile performance was the best when the fibers were arranged in the 0° direction when the strength utilisation rate was the highest. In addition, by observing the failure morphologies of the composites, the delamination and foam cracking were found in the four groups of composites. In contrast, the phenomenon of significant fracture was found on composites with a laying angle of [45°/-45°]4 only, indicating it had a poor bending resistance performance.

7

Bending Failure Behavior of the Glass Fiber Reinforced Composite I-Beams Formed by a Novel Bending Pultrusion Processing Technique

Zhu Lvtao, Cao Shengbin, Zhang Xiaofeng, Li Lei

Autex Research Journal

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2022

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Vol. 22, no. 2

172--176

EN

The glass fiber reinforced resin matrix composite I-beams were designed and formed via a type of novel bending pultrusion processing technique, and the three-point bending tests were carried out to analyze the mechanical bending performances. The obtained results show that the main failure mode of the composite I-beam under the bending load is the upper structure (top flange) cracks along the length direction of the fibers, and the cracks simultaneously propagate downwards in the vertical direction. The bifurcated cracks can be found at the junction area between the top flange and web. In addition, the main bending failure mechanism of the composite I-beam includes the matrix cracking, propagation of cracks, and final fracture failure. In particular, noting that when the crack reaches the I-shaped neck position, the lateral bifurcation occurs, and the resulting secondary cracks further extend in two directions, which leads to the serious damage between the top flange and web, and the ultimate fracture failure occurs.

8

Wpływ cyklicznych obciążeń mechanicznych na odporność korozyjną aluminium

Strąk Adrian, Francke Barbara

Materiały Budowlane

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2021

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nr 6

2--6

PL

W artykule zaprezentowano wpływ zmęczeniowych obciążeń mechanicznych na odporność korozyjną profili okiennych i drzwiowych wykonanych ze stopu aluminium EN AW-6063 z powłoką poliestrową. W badaniach zastosowano własną metodę oceny, polegającą na cyklicznych obciążeniach skupionych działających na próbkę metodą trójpunktowego zginania. Efektem tych obciążeń było powstanie w obrębie struktury aluminium trwałego odkształcenia plastycznego, podczas gdy w przypadku powłoki pokrywającej profile aluminiowe nastąpiło niewielkie zmniejszenie odporności korozyjnej, niepowodujące jednak utraty właściwości barierowych. Stwierdzono również, że gdy obciążeniom mechanicznym towarzyszy działanie kwaśnej mgły solnej, pojawiają się mikrouszkodzenia w strukturze powłok, w istotny sposób zmniejszając ich właściwości barierowe, co potwierdzono wynikami badań spektroskopii impedancyjnej.

EN

The article presents the effect of mechanical load fatigue on corrosion resistance of profiles made of EN AW-6063 aluminium alloy with polyester coating. In test, own research methodology was used, consisting in cyclical application of concentrated load to the tested sample with the three-point bending method. The effect of these loads was the formation of a permanent plastic deformation within the aluminium structure, while in the case of the coating covering aluminium profiles, there is a slight reduction in corrosion resistance, without the loss of barrier properties, however. It was also found that when in addition to mechanical load, salt spray test was applied, microdamage in the coatings’ structure appeared, significantly reducing their barrier properties, which was confirmed by the results of impedance spectroscopy.

9

Study of mechanical behaviour in three-point bending of fatigue-stressed composite laminates

Khelifa Noureddine, Bey Kamel, Mzad Hocine

Composites Theory and Practice

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2021

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R. 21, nr 3

107--113

EN

The aim of this work was to conduct an experimental investigation of the mechanical behaviour in the three-point bending of fatigue-stressed cross-ply laminated composites. A 3-point static bending study was carried out on two types of laminated composite materials to determine their mechanical characteristics as well as to assess the influence of the test speed and the effect of the stacking sequence on their mechanical behaviour. Different damage modes leading to the rupture of these materials were highlighted to determine their types.

10

Gięcie na zimno dwuteownika HL1100

Marcinczak Krzysztof, Marcinczak Dorota

Builder

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2020

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R.24, nr 4

114--116

PL

W artykule opisano badanie w skali naturalnej trójpunktowego zginania na zimno dwuteownika HL1000. Przedstawiono przebieg badania oraz wybrane wyniki odkształceń uzyskane podczas nadawania podniesienia wykonawczego. Podczas badania wykorzystano innowacyjną metodę pomiarów światłowodowych.

EN

The paper presents point cold bending of I-beam HL1100 – full-scale test. The implementation and selected results of deformations during cambering were presented. During The innovative method of measuring by fiber optics were used in research.

11

Numerical and experimental verification of impact response of laminated aluminum composite structure

Wang Jifeng, Morris Tyler P., Bihamta Reza, Pan Ye-Chen

Archive of Mechanical Engineering

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2020

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LXVII, nr 2

127-147

EN

Laminated Aluminum Composite Structure (LACS) has shown great potential for replacing traditional bulk aluminum parts, due to its ability to maintain low manufacturing costs and create complex geometries. In this study, a LACS, that consists of 20 aluminum layers joined by a structural tape adhesive, was fabricated and tested to understand its impact performance. Three impact tests were conducted: axial drop, normal and transverse three-point bending drop tests. Numerical simulations were performed to predict the peak loads and failure modes during impacts. Material models with failure properties were used to simulate the cohesive failure, interfacial failure, and aluminum fracture. Various failure modes were observed experimentally (large plastic deformation, axial buckling, local wrinkling, aluminum fracture and delamination) and captured by simulations. Cross-section size of the axial drop model was varied to understand the LACS buckling direction and force response. For threepoint bending drop simulations, the mechanism causing the maximum plastic strain at various locations in the aluminum and adhesive layers was discussed. This study presents an insight to understand the axial and flexural responses under dynamic loading, and the failure modes in LACS. The developed simulation methodology can be used to predict the performance of LACS with more complex geometries.

12

Effect of the recyclate on a deflection of composites in bending

Panasiuk Katarzyna, Kyzioł Lesław, Hajdukiewicz Grzegorz

Journal of KONES

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2019

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Vol. 26, No. 4

197--203

EN

The aim of the research was to determine the effect of polyester-glass recyclate on the deflection of composite samples subjected to three-point bending. The polyester-glass recyclate was obtained from the part of the ship’s hull made of polyester-glass composite, constituting scrap metal. The pieces of scrap were pre-fragmented and then processed into a prepared stand for this purpose. Such a fragmented recycling will be used to make composites with different scrap / recycled content. For this purpose, research materials were made using the vacuum bag method with the percentage of 0%, 10% and 20% recyclate) as well as various granulation (i.e. 1.2 mm and 3.0 mm). The research material consisted of rectangular plates with a thickness corresponding to the thickness of the samples. The samples for testing were made by water cutting. The tests were carried out on a suitably prepared stand, which was made of a universal Zwick Roell testing machine and three-point bending handles and a dial indicator. The spacing of the supports has been determined in accordance with the binding standard for three-point bending. Obtained results from tests, i.e. strain, stress, deflection, deformation allowed analysing the impact of recyclate on bending strength and defining the deflection arrow. Based on the results obtained from three-point bending, it can be concluded that the polyester-glass recycling has an influence on the decrease of strength, stress and deflections of the tested composites.

13

Finite element analysis of three-point bending of a T-beam structural biaxial highly oriented polymer material

Wei C.-L., Chang Y., Lee Y.-C., Lee R., Luo T.-W., Chen J.-H.

Polimery

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2018

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T. 63, nr 3

219--223

EN

Polymers with biaxial aligned molecular chains are also orthotropic materials, which are characterized by high tensile strength and low shear strength in the length direction. When orthotropic materials are used as structural shapes with poor shear strength, they are likely to undergo premature failure under shear stress. Therefore, in three-point bending, the cross-section of the entire profile not only bears tensile stress and compressive stress in the length direction, but also simultaneously exhibits shear stress. This study analyzes the distribution of tensile stress, compressive stress and shear stress in the length direction of highly oriented polymers (HOP) by finite element analysis to find the most suitable length-to-height ratio for these materials when used as structural shapes. The finite element analysis software, Abaqus, is utilized to simulate HOP T-beam to analyze the load stress of a T-beam. With a fixed cross–section area, as the length of the material changes, its shear strength also changes. Accordingly, the order of occurrence of tensile failure and shear failure can be investigated. The simulation reveals that when the length-to-height ratio is between 4 : 1 and 20 : 1, a zone of stress in which tensile failure and shear failure occur can be found. This result can be exploited in the design and development of structural beam.

PL

Polimery o dwuosiowo zorientowanych łańcuchach makrocząsteczek są materiałami ortotropowymi, wykazującymi dużą wytrzymałość na rozciąganie oraz niewielką wytrzymałość na ścinanie w kierunku długości. Elementy konstrukcyjne wytworzone z materiału ortotropowego o małej wytrzymałości na ścinanie są podatne na przedwczesne uszkodzenie pod wpływem naprężeń ścinających. Przy zginaniu trójpunktowym w przekroju ich profilu występują zarówno naprężenia rozciągające i ściskające w kierunku podłużnym, jak i naprężenia ścinające. Metodą elementów skończonych analizowano rozkład naprężeń rozciągających, ściskających i ścinających w kierunku podłużnym wysoko zorientowanych polimerów (HOP) w celu określenia optymalnego stosunku długości do wysokości w kształtach konstrukcyjnych. Do symulacji naprężeń obciążeniowych w zginaniu trójpunktowym belki teowej wykorzystano program komputerowy Abaqus. Stwierdzono, że przy stałej powierzchni przekroju poprzecznego belki jej wytrzymałość na ścinanie zmienia się wraz ze zmianą długości. Badano również kolejność występowania uszkodzeń pod wpływem działania sił rozciągających i ścinających. Symulacja wykazała, że przy stosunku długości do wysokości w zakresie od 4 : 1 do 20 : 1 występuje strefa naprężeń, w której mogą się pojawiać uszkodzenia w wyniku rozciągania lub ścinania. Uzyskane wyniki można wykorzystać w projektowaniu i optymalizacji belek konstrukcyjnych.

14

Mechanical response of notched marble beams under bending versus acoustic emissions and electric activity

Kourkoulis S. K., Pasiou E. D., Dakanali I., Stavrakas I., Triantis D.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 2

523--547

EN

An experimental protocol, including the combined application of both innovative and traditional sensing techniques, is described aiming to explore the mechanical response of marble and also to check the possibilities of detecting precursor phenomena designating upcoming catastrophic fracture. The protocol consisted of three-point bending tests with notched prismatic beams made of Dionysos marble, the material extensively used for restoration of the Acropolis of Athens monuments. The sensing system improvised included techniques relying on completely different physical foundations, which permit simultaneous detection and recording of the Pressure Stimulated Currents, Acoustic Emissions, three dimensional displacement fields and Notch Mouth Opening Displacements. Analysis of the results revealed interesting features of the mechanical response of Dionysos marble and indicated, also, that classical Continuum Fracture Mechanics fails to describe accurately the response of marble, at least in the presence of notches. In addition, strong correlations between the Pressure Stimulated Currents, the rate of acoustic hits and the rate of change of the opening of the pre-existing notch have been enlightened. Moreover, the onset of catastrophic crack propagation appears following distinguishable changes of the Pressure Stimulated Currents recorded. Therefore (and taking into account the very small size of the respective sensors as well as the simple complementary equipment needed), it is concluded that the specific technique could be considered as a simple and reliable tool for an alternative approach to the in-situ Structural Health Monitoring of classical stone monuments.

15

Analytical modeling of I-beam as a sandwich structure

Magnucki K., Lewinski J.

Engineering Transactions

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2018

|

Vol. 66, iss. 4

357--373

EN

The paper is devoted to an analytical model of I-beam, with consideration of the shear effect. The model is based on the sandwich beam theory. The field displacements and strains are formulated with consideration of a nonlinear hypothesis of flat cross-section deformation of the beam. The governing differential equations for the I-beam are obtained based on the principle of stationary total potential energy. The shear effect of the beam is illustrated for the threepoint bending case. The analytical solution is compared to FEM numerical calculation. The results of the analysis are presented in Tables and Figures.

16

Three point bending of hand laminated fiber composites

Łagoda K., Osiecki T., Kurek A., Lewandowski T.

Composites Theory and Practice

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2018

|

R. 18, nr 2

82--87

EN

The article describes the course and results of research on a composite laminate. Specimens were made from glassreinforced epoxy resin using the hand lamination technique with the fibres arranged unidirectionally along the specimen. The dimensions were selected on the basis of DIN EN ISO 14125. Strain gauges were placed on the surface of every specimen, then testing was conducted - three point bending. The specimen was placed so that the strain gauge was at the stretched side during bending in order to measure the strain. The stress was also calculated analytically, based on the process parameters. As a result, the theoretical stresses were compared with the experimental ones.

PL

Opisano przebieg i wyniki badań laminatu kompozytowego. Materiałem, z którego wykonano próbki, była żywica epoksydowa wzmocniona włóknem szklanym. Próbki do badań zostały przygotowane w technologii laminowania ręcznego. Włókna ułożone były jednokierunkowo, wzdłuż próbki. Wymiary zostały dobrane na podstawie normy DIN EN ISO 14125. Na powierzchni próbki umieszczono tensometry. Następnie przeprowadzono badania - zginanie trójpunktowe. Próbkę umieszczono tak, aby tensometr był od strony rozciągania podczas zginania, dzięki czemu mierzone było odkształcenie. Naprężenia były obliczane również w sposób analityczny, na podstawie parametrów procesu. W wyniku uzyskano porównanie naprężeń teoretycznych z doświadczalnymi.

17

Wpływ właściwości mechanicznych okładzin i rdzenia na stateczność belek trójwarstwowych poddanych zginaniu trójpunktowemu

Wstawska I.

Technical Issues

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2017

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nr 2

42--47

EN

The objective of this work is the numerical analysis of the stability of three-layered beams with a metal foam core. The beams were subjected to three-point bending. The analysis of the local buckling and the influence of material properties of the faces and the core on critical loads and buckling shape was performed. The calculations were made in elastic range on a family of beams with different mechanical properties of the faces and the core. Calculations of critical loads and buckling shape were performed. The analysis of the finite element model (FEM) of three-layered beam has been performed with the use of ANSYS software. The upper and the lower face have been retreated from the core by half of the thickness. Tie constrains have been applied between the core and the faces. Due to symmetry of the model only a quarter of the beam has been modelled with proper boundary conditions on the symmetry planes.

18

Influence of additive manufacturing technology on mechanical properties of glass-filled fine polyamide PA3200GF

Bajerski P., Pęcherski R. B.

Engineering Transactions

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2017

|

Vol. 65, iss. 1

155--161

EN

Additive manufacturing is a very fast developing field of research and many parts with complicated geometry are now made using 3D printing. The injection molding, casting, milling and other processes have some limitations and low volume of production makes these processes quite expensive. 3D printing allows to fabricate parts with enough mechanical strength and without looking at the above mentioned limitations. Nowadays, designers are able to fabricate prototypes with not only optimized but also complex shape. Unfortunately, the parts made from thermoplastic materials by means of 3D technique have lower mechanical strength in comparison to the parts made by using injection molding process. The orientation of layers, thickness of a layer, porosity, and process parameters have a big influence on mechanical properties of the fabricated parts. In this paper, the experimental results from the static tensile tests, the compression tests and the dynamic three-point bending test are presented. The tests were performed for different orientations of printing specimens. It was shown that to assess the mechanical properties of printing parts (made by using selective laser sintering (SLS) technique)our own measurements need to be obtained. The available catalogue data are not sufficient for further investigations like in the finite element (FE) analyses.

19

Cienkościenne zamknięte profile aluminiowe łączone za pomocą warstwy adhezyjnej – charakterystyka przy trójpunktowym zginaniu

Sadowski T., Nowicki M.

Przegląd Budowlany

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2016

|

R. 87, nr 2

30--33

PL

Profile cienkościenne znajdują obecnie szerokie zastosowanie w budownictwie. Wykorzystywane są jako materiały konstrukcyjne, elementy stolarki czy elementy wykończeniowe. Jednak łączenie ich za pomocą kleju to jeszcze dość mało rozpowszechnione metody, chociaż w ostatnim czasie wzrasta zainteresowanie technikami klejenia konstrukcji metalowych w budownictwie. Opracowanie przedstawione w pracy dotyczy analizy klejonego cienkościennego profilu aluminiowego o przekroju poprzecznym omega, który poddano 3-punktowemu zginaniu. W artykule przedstawiono wyniki badań laboratoryjnych oraz modelowania numerycznego quasi-statycznego zginania tych elementów w dwóch ułożeniach profili.

EN

Nowadays, thin-walled profiles are widely used in building industry. They are used as construction materials, woodwork elements or finishing elements. However, joining them with the use of an adhesive material is not a widely recognized method yet, although recently growing interest in techniques of gluing the metal structures in building industry could have been observed. The study presented in this paper discusses the analysis of glued thin-walled aluminum profile with omega cross-section, which has been subject to 3-point bending. The article presents the results of laboratory testing and of numerical modeling of quasi-static bending of these elements in two profile positions.

20

Analysis of the composite material behaviour subjected to dynamic bending using the hopkinson bar

Massaq A., Rusinek A., Klósak M., Boulouz A., Koutti L.

Engineering Transactions

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2016

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Vol. 64, iss. 1

115--131

EN

The aim of this study is to propose an experimental approach supported by an analytical analysis for polymer materials under dynamic loading. The experimental technique of Hopkinson split pressure bar is used which allows for high impact velocities. The specimens are subjected to the three-point bending and the efficiency of the experimental technique is proved. During quasi-static and dynamic bending tests, the rupture mode is described and the evolution of the energy and the ultimate stresses as a function of the initial impact velocity is discussed. In addition, the critical impact velocity estimated above an important change in the rupture mode is observed. In order to better describe the physical phenomena encountered during the three-point bending impact, the analysis is supported by a rheological model based on a mass-spring system.