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22 pages, 7434 KiB

Open AccessArticle

Effect of Cu Content on the Alloy Tensile Properties of Al-Cu Based Alloys Tested at 25 °C and 250 °C: Application of the Concept of Quality Index

by Abram Girgis, Ehab Samuel, Agnes M. Samuel, Victor Songmene and Fawzy H. Samuel

Materials 2023, 16(4), 1400; https://doi.org/10.3390/ma16041400 - 7 Feb 2023

Cited by 1 | Viewed by 1222

Abstract

The present work was performed on three versions of a newly developed alloy coded T200 containing 6.5% Cu, 0.1% Fe, 0.45% Mg, and 0.18% Zr in addition to A319 and A356 alloys (grain refined and Sr-modified). Tensile bars were subjected to 13 different [...] Read more.

The present work was performed on three versions of a newly developed alloy coded T200 containing 6.5% Cu, 0.1% Fe, 0.45% Mg, and 0.18% Zr in addition to A319 and A356 alloys (grain refined and Sr-modified). Tensile bars were subjected to 13 different heat treatments prior to testing at either 25 °C or 250 °C. The tensile data were analyzed using the quality index method. The results obtained showed that, due to the high copper content in the T200 alloy coupled with proper grain refining, the alloy possesses the highest quality as well as improved resistance to softening when tested at 250 °C among the five alloys. The results also demonstrate the best heat treatment condition to maximize the use of the T200 alloy for automotive applications. Grain-refined alloy B, treated in the T6 temper and tested at 250 °C, exhibited the best combination of the four tensile parameters, i.e., UTS, YS, %El, and Q-values: 308 MPa, 304 MPa, 2.3%, and 352 MPa, respectively, which are comparable with those obtained from the 356 alloy: 309 MPa, 305 MPa, 2.8%, and 375 MPa in the same order. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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17 pages, 5994 KiB

Open AccessArticle

Dismantling of Reinforced Concrete Using Steam Pressure Cracking System: Drilling and Crack Propagation

by Osamu Kamiya, Mamoru Takahashi, Yasuyuki Miyano, Shinichi Ito, Kenji Murata, Makoto Kawano, Arata Maisawa, Jumpei Nanao, Takashi Kazumi, Masanobu Nakatsu, Hiroyuki Mizuma, Tatsuya Miyota, Kota Nagao and Yuichi Iwama

Materials 2023, 16(4), 1398; https://doi.org/10.3390/ma16041398 - 7 Feb 2023

Cited by 2 | Viewed by 1156

Abstract

This study investigated a new dismantling system for concrete structures using a steam pressure cracking agent. We improved the mechanical systems such that it can drill through reinforcing steel bars. Therefore, the control method of the system and shape of the drill tip [...] Read more.

This study investigated a new dismantling system for concrete structures using a steam pressure cracking agent. We improved the mechanical systems such that it can drill through reinforcing steel bars. Therefore, the control method of the system and shape of the drill tip were improved. When the drill tip is stuck with chips and stopped, it is automatically pulled out and reinserted to recover the rotation. By changing the tip angle of the drill bit from 75° to 90°, it became possible to cut reinforcing bars, which were difficult to cut previously. In addition, we designed a crawler-type mechanical system and improved it such that it can be moved to the appropriate position and operated at any angle. This study revealed that the energy required for the drilling process accounts for more than 90% of the total dismantling energy. Through experiments using an impact hammer drill and observations of fracture surfaces using a three-dimensional scanner, we analysed the characteristics of reinforced concrete. In addition, the feasibility of the design for dismantling reinforced concrete was confirmed based on the determined energy associated with crack propagation. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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23 pages, 20852 KiB

Open AccessArticle

Effect of Si, Mn, Be and Sr Addition on the Tensile Properties of 6061 Type Alloys: Role of Aging Treatment

by Agnes M. Samuel, Ehab A. Elsharkawi, Mohamed H. Abdelaziz, Ehab Samuel and Fawzy H. Samuel

Materials 2023, 16(3), 1110; https://doi.org/10.3390/ma16031110 - 27 Jan 2023

Cited by 1 | Viewed by 1647

Abstract

The present study was performed on a 6061-type alloy to examine the effects of minor additions (Si, Mn, Be, Sr) of the type of precipitated Fe-based intermetallics, in terms of Fe/Si ratios. All alloys were grain refined (0.15%Ti in the form of Al-5%Ti-1%B) [...] Read more.

The present study was performed on a 6061-type alloy to examine the effects of minor additions (Si, Mn, Be, Sr) of the type of precipitated Fe-based intermetallics, in terms of Fe/Si ratios. All alloys were grain refined (0.15%Ti in the form of Al-5%Ti-1%B) to minimize hot tearing during casting. The effect of these intermetallics on the alloy tensile properties was also investigated. Tensile test bars were solutionized at 520 °C followed by quenching in warm water at 60 °C to avoid cracking. The quenched bars were aged at 175 °C for periods up to 100 h. Characterization of the formed intermetallics as well as phase precipitation were carried out using field emission scanning electron microscopy. In Be-treated alloys, α-Al₈Fe₂SiBe phase may precipitate along with α-Al₁₅(Fe, Mn)₃Si₂ phase. In addition, Be results in fragmentation of the α-Fe phase when the alloy was Sr-modified, leading to better tensile properties, compared to those obtained from the base alloy under same conditions. It should be noted that this study does not promote the use of Be as it is a toxic element. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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17 pages, 6702 KiB

Open AccessArticle

Material Removal Capability and Profile Quality Assessment on Silicon Carbide Micropillar Fabrication with a Femtosecond Laser

by Xifang Zhang, Zhibao Hou, Jiacheng Song, Zhiyi Jin and Zhenqiang Yao

Materials 2023, 16(1), 244; https://doi.org/10.3390/ma16010244 - 27 Dec 2022

Viewed by 1513

Abstract

Silicon carbide (SiC) has a variety of applications because of its favorable chemical stability and outstanding physical characteristics, such as high hardness and high rigidity. In this study, a femtosecond laser with a spiral scanning radial offset of 5 μm and a spot [...] Read more.

Silicon carbide (SiC) has a variety of applications because of its favorable chemical stability and outstanding physical characteristics, such as high hardness and high rigidity. In this study, a femtosecond laser with a spiral scanning radial offset of 5 μm and a spot radius of 6 μm is utilized to process micropillars on a SiC plate. The influence of pulsed laser beam energies and laser translation velocities on the micropillar profiles, dimensions, surface roughness Ra, and material removal capability (MRC) of micropillars was investigated. The processing results indicate that the micropillar has the best perpendicularity, with a micropillar bottom angle of 75.59° under a pulsed beam energy of 50 μJ in the range of 10–70 μJ, with a pulsed repetition rate of 600 kHz and a translation velocity of 0.1 m/s. As the laser translation velocity increases between 0.2 m/s and 1.0 m/s under a fixed pulsed beam energy of 50 μJ and a constant pulsed repetition rate of 600 kHz, the micropillar height decreases from 119.88 μm to 81.79 μm, with the MRC value increasing from 1.998 μm³/μJ to 6.816 μm³/μJ, while the micropillar bottom angle increases from 68.87° to 75.59°, and the Ra value diminishes from 0.836 μm to 0.341 μm. It is suggested that a combination of a higher pulsed laser beam energy with a faster laser translation speed is recommended to achieve micropillars with the same height, as well as an improved processing efficiency and surface finish. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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28 pages, 12099 KiB

Open AccessArticle

Static and Fatigue Behaviour of Double-Lap Adhesive Joints and Notched Metal Samples Reinforced by Composite Overlays

by Paweł J. Romanowicz, Bogdan Szybiński and Mateusz Wygoda

Materials 2022, 15(9), 3233; https://doi.org/10.3390/ma15093233 - 29 Apr 2022

Cited by 3 | Viewed by 1811

Abstract

The use of composite overlays to increase the fatigue life of notched steel samples is discussed in this paper. For such purposes, in the first set of studies, static and fatigue tests as well as the detailed analytical and numerical analyses for samples [...] Read more.

The use of composite overlays to increase the fatigue life of notched steel samples is discussed in this paper. For such purposes, in the first set of studies, static and fatigue tests as well as the detailed analytical and numerical analyses for samples with double-lap joints were performed. Based on such studies, the shapes of the composite overlays were set. For a better understanding of the failure forms of the investigated adhesive joints, the experimental studies were monitored with the use of digital image correlation. In the second set of experimental studies, the static and fatigue tensile tests were performed for steel samples with a rectangular opening with rounded corners reinforced by composite overlays. The different shapes (square 45 × 45 mm and long stripes 180 × 15 mm) and composite materials (GFRP and CFRP) were used as overlays. The obtained improvement of fatigue life was in the range of 180–270% in the case of the rectangular overlays and 710% in the case of application of the overlays in the form of the long stripes. This was also confirmed by numerical analyses in which a reduction in the stress concentration factor from 2.508 (bare sample) through 2.014–2.183 (square 45 × 45 mm overlays) to 1.366 (overlays in the form of long stripes 180 × 15 mm) was observed. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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9 pages, 26589 KiB

Open AccessArticle

Machinability of Different Wood-Plastic Composites during Peripheral Milling

by Zhaolong Zhu, Dietrich Buck, Jinxin Wang, Zhanwen Wu, Wei Xu and Xiaolei Guo

Materials 2022, 15(4), 1303; https://doi.org/10.3390/ma15041303 - 10 Feb 2022

Cited by 24 | Viewed by 2385

Abstract

The aim of this study was to improve the machinability of wood-plastic composites by exploring the effects of different wood-plastic composites on machinability. In particular, the effects of milling with cemented carbide cutters were assessed by investigating cutting forces, cutting temperature, surface quality, [...] Read more.

The aim of this study was to improve the machinability of wood-plastic composites by exploring the effects of different wood-plastic composites on machinability. In particular, the effects of milling with cemented carbide cutters were assessed by investigating cutting forces, cutting temperature, surface quality, chip formation, and tool wear. The cutting parameters determined to yield an optimal surface quality were rake angle 2°, cutting speed 9.0 m/s, feed per tooth 0.3 mm, and cutting depth 1.5 mm. In these optimized milling conditions, the wood-plastic composite with polypropylene exhibited the highest cutting forces, cutting temperature, and tool wear, followed by polyethylene and polyvinyl chloride wood-plastic composites. Two wear patterns were determined during wood-plastic composite machining, namely chipping and flaking. Due to the different material composition, semi-discontinuous ribbon chips and continuous ribbon chips were generated from the machining process of wood-plastic composites with polypropylene and polyethylene, respectively. The wood-plastic composite with polyvinyl chloride, on the other hand, formed needle-like chips. These results contribute to a theoretical and practical basis for improved wood-plastic composite machining in industrial settings. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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12 pages, 3447 KiB

Open AccessArticle

Effects of Particle Size Distribution with Efficient Packing on Powder Flowability and Selective Laser Melting Process

by Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa and Lianyi Chen

Materials 2022, 15(3), 705; https://doi.org/10.3390/ma15030705 - 18 Jan 2022

Cited by 18 | Viewed by 5722

Abstract

The powder bed-based additive manufacturing (AM) process contains uncertainties in the powder spreading process and powder bed quality, leading to problems in repeatability and quality of the additively manufactured parts. This work focuses on identifying the uncertainty induced by particle size distribution (PSD) [...] Read more.

The powder bed-based additive manufacturing (AM) process contains uncertainties in the powder spreading process and powder bed quality, leading to problems in repeatability and quality of the additively manufactured parts. This work focuses on identifying the uncertainty induced by particle size distribution (PSD) on powder flowability and the laser melting process, using Ti6Al4V as a model material. The flowability test results show that the effect of PSDs on flowability is not linear, rather the PSDs near dense packing ratios cause significant reductions in flowability (indicated by the increase in the avalanche angle and break energy of the powders measured by a revolution powder analyzer). The effects of PSDs on the selective laser melting (SLM) process are identified by using in-situ high-speed X-ray imaging to observe the melt pool dynamics during the melting process. The results show that the powder beds made of powders with dense packing ratios exhibit larger build height during laser melting. The effects of PSD with efficient packing on powder flowability and selective laser melting process revealed in this work are important for understanding process uncertainties induced by feedstock powders and for designing mitigation approaches. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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22 pages, 6582 KiB

Open AccessArticle

Stability Loss Analysis for Thin-Walled Shells with Elliptical Cross-Sectional Area

by Ján Kostka, Jozef Bocko, Peter Frankovský, Ingrid Delyová, Tomáš Kula and Patrik Varga

Materials 2021, 14(19), 5636; https://doi.org/10.3390/ma14195636 - 28 Sep 2021

Cited by 2 | Viewed by 1571

Abstract

The aim of the scientific contribution is to point out the possibility of applicability of cylindrical shells with a constant elliptical cross-sectional shape for stability loss analysis. The solution to the problem consists of two approaches. The first approach is the experimental measurement [...] Read more.

The aim of the scientific contribution is to point out the possibility of applicability of cylindrical shells with a constant elliptical cross-sectional shape for stability loss analysis. The solution to the problem consists of two approaches. The first approach is the experimental measurement of critical force levels, where the work also describes the method of production of the sample and jigs that cause the desired elliptical shape. The second approach is solving the problem in the use of numerical methods—the finite strip method together with the finite element method. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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18 pages, 8376 KiB

Open AccessArticle

The Influence of CNC Turning with VBMT, RCMX, 3ER, and MGMN Type Indexable Inserts on West African Ebony/Diospyros crassiflora, San Domingo Boxwood/Phyllostylon brasiliense, Rio Rosewood/Dalbergia nigra, Beechwood/Fagus sylvatica, Oakwood/Quercus robur, and Pinewood/Pinus silvestris Surface Roughness

by Michał Bembenek, Rafał Kudelski, Jan Pawlik and Łukasz Kowalski

Materials 2021, 14(19), 5625; https://doi.org/10.3390/ma14195625 - 27 Sep 2021

Cited by 5 | Viewed by 1803

Abstract

The current scientific literature lacks an adequate description of hardware used to machine timber. Traditional woodworking and metals fabrication consists of tungsten carbide (TC) inserts. In this work, the authors investigate the influence of cutting tool geometry on the resulting surface roughness of [...] Read more.

The current scientific literature lacks an adequate description of hardware used to machine timber. Traditional woodworking and metals fabrication consists of tungsten carbide (TC) inserts. In this work, the authors investigate the influence of cutting tool geometry on the resulting surface roughness of timber samples. A variety of wood types were used in these studies to provide broad information on the correlation between the cutting tools used and resulting surface morphology. The cutting tools were prepared on a computer numerical control (CNC) lathe and roughness average (R_a) and average maximum peak to valley height of the profile (R_z) parameters were measured by contact stylus. The tip radius of the TC inserts used was determined to be the most significant factor that impacted R_a and R_z. In summary, we found that the tip radius of the TC insert was inversely proportional to the roughness level, indicating that a flatter TC insert cutting end results in a smoother wood surface. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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17 pages, 9043 KiB

Open AccessArticle

The Influence of Welding Heat Source Inclination on the Melted Zone Shape, Deformations and Stress State of Laser Welded T-Joints

by Zbigniew Saternus, Wiesława Piekarska, Marcin Kubiak and Tomasz Domański

Materials 2021, 14(18), 5303; https://doi.org/10.3390/ma14185303 - 14 Sep 2021

Cited by 4 | Viewed by 1965

Abstract

The paper concerns the numerical analysis of the influence for three different of welding heat source inclinations on the weld pool shape and mechanical properties of the resulting joint. Numerical analysis is based on the experimental tests of single-side welding of two sheets [...] Read more.

The paper concerns the numerical analysis of the influence for three different of welding heat source inclinations on the weld pool shape and mechanical properties of the resulting joint. Numerical analysis is based on the experimental tests of single-side welding of two sheets made of X5CrNi18-10 stainless steel. The joint is made using a laser welding heat source. Experimental test was performed for one heating source inclination. As a part of the work metallographic tests are performed on which the quality of obtained joints are determined. Numerical calculations are executed in Abaqus FEA. The same geometrical model is assumed as in the experiment. Material model takes into account changing with temperature thermophysical properties of austenitic steel. Modeling of the motion of heating source is performed in additional subroutine. The welding source parameters are assumed in accordance with the welding process parameters. Numerical calculations were performed for three different inclinations of the source. One inclination is consistent with experimental studies. The performed numerical calculations allowed to determine the temperature field, shape of welding pool as well as deformations and stress state in welded joint. The obtained results are compared to results of the experiment. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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19 pages, 4762 KiB

Open AccessArticle

The Impact of Long-Term Physical Salt Attack and Multicycle Temperature Gradient on the Mechanical Properties of Spun Concrete

by Romualdas Kliukas, Arūnas Jaras and Ona Lukoševičienė

Materials 2021, 14(17), 4811; https://doi.org/10.3390/ma14174811 - 25 Aug 2021

Cited by 5 | Viewed by 1683

Abstract

The article is focused on spun concrete made with different chemical admixtures under long-term exposure to aggressive salt-saturated ground water and a cyclic temperature gradient. Over a long-term experimental investigation, 64 prismatic spun concrete specimens were subjected to multicycle (75–120) processing under combined [...] Read more.

The article is focused on spun concrete made with different chemical admixtures under long-term exposure to aggressive salt-saturated ground water and a cyclic temperature gradient. Over a long-term experimental investigation, 64 prismatic spun concrete specimens were subjected to multicycle (75–120) processing under combined aggressive ambient conditions. Prismatic specimens were soaked in water or saline and dried at a temperature of 45–50 °C. The long-term multi-cycle effect of the temperature gradient and physical salt attack on the compressive strength, Young’s modulus and durability of concrete was found to be negative. Chemical admixtures, though, improved the structure of spun concrete, thus having a significant positive effect on its physical-mechanical properties and durability. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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16 pages, 11449 KiB

Open AccessArticle

Effect of Flue Gases’ Corrosive Components on the Degradation Process of Evaporator Tubes

by Mária Hagarová, Milan Vaško, Miroslav Pástor, Gabriela Baranová and Miloš Matvija

Materials 2021, 14(14), 3860; https://doi.org/10.3390/ma14143860 - 10 Jul 2021

Cited by 7 | Viewed by 3128

Abstract

Corrosion of boiler tubes remains an operational and economic limitation in municipal waste power plants. The understanding of the nature, mechanism, and related factors can help reduce the degradation process caused by corrosion. The chlorine content in the fuel has a significant effect [...] Read more.

Corrosion of boiler tubes remains an operational and economic limitation in municipal waste power plants. The understanding of the nature, mechanism, and related factors can help reduce the degradation process caused by corrosion. The chlorine content in the fuel has a significant effect on the production of gaseous components (e.g., HCl) and condensed phases on the chloride base. This study aimed to analyze the effects of flue gases on the outer surface and saturated steam on the inner surface of the evaporator tube. The influence of gaseous chlorides and sulfates or their deposits on the course and intensity of corrosion was observed. The salt melts reacted with the steel surface facing the flue gas flow and increased the thickness of the oxide layer up to a maximum of 30 mm. On the surface not facing the flue gas flow, they disrupted the corrosive layer, reduced its adhesion, and exposed the metal surface. Beneath the massive deposits, a local overheating of the inner surface of the evaporator tubes occurred, which resulted in the release of the protective magnetite layer from the surface. Ash deposits reduce the boiler’s thermal efficiency because they act as a thermal resistor for heat transfer between the flue gases and the working medium in the pipes. The effect of insufficient feedwater treatment was evinced in the presence of mineral salts in the corrosion layer on the inner surface of the tube. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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16 pages, 924 KiB

Open AccessEditor’s ChoiceArticle

Optimization of Extrusion-Based 3D Printing Process Using Neural Networks for Sustainable Development

by Izabela Rojek, Dariusz Mikołajewski, Marek Macko, Zbigniew Szczepański and Ewa Dostatni

Materials 2021, 14(11), 2737; https://doi.org/10.3390/ma14112737 - 22 May 2021

Cited by 26 | Viewed by 3734

Abstract

Technological and material issues in 3D printing technologies should take into account sustainable development, use of materials, energy, emitted particles, and waste. The aim of this paper is to investigate whether the sustainability of 3D printing processes can be supported by computational intelligence [...] Read more.

Technological and material issues in 3D printing technologies should take into account sustainable development, use of materials, energy, emitted particles, and waste. The aim of this paper is to investigate whether the sustainability of 3D printing processes can be supported by computational intelligence (CI) and artificial intelligence (AI) based solutions. We present a new AI-based software to evaluate the amount of pollution generated by 3D printing systems. We input the values: printing technology, material, print weight, etc., and the expected results (risk assessment) and determine if and what precautions should be taken. The study uses a self-learning program that will improve as more data are entered. This program does not replace but complements previously used 3D printing metrics and software. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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21 pages, 21067 KiB

Open AccessArticle

Investigation of Compression and Buckling Properties of a Novel Surface-Based Lattice Structure Manufactured Using Multi Jet Fusion Technology

by Aamer Nazir, Mubasher Ali and Jeng-Ywan Jeng

Materials 2021, 14(10), 2599; https://doi.org/10.3390/ma14102599 - 17 May 2021

Cited by 12 | Viewed by 3316

Abstract

Lattice structures possess many superior properties over solid materials and conventional structures. Application-oriented lattice structure designs have become a choice in many industries, such as aerospace, automotive applications, construction, biomedical applications, and footwear. However, numerical and empirical analyses are required to predict mechanical [...] Read more.

Lattice structures possess many superior properties over solid materials and conventional structures. Application-oriented lattice structure designs have become a choice in many industries, such as aerospace, automotive applications, construction, biomedical applications, and footwear. However, numerical and empirical analyses are required to predict mechanical behavior under different boundary conditions. In this article, a novel surface-based structure named O-surface structure is designed and inspired by existing Triply Periodic Minimal Surface morphologies in a particular sea urchin structure. For comparison, both structures were designed with two different height configurations and investigated for mechanical performance in terms of compression, local buckling, global buckling, and post-buckling behavior. Both simulation and experimental methods were carried out to reveal these aforementioned properties of samples fabricated by multi jet fusion technology. The sea urchin structure exhibited better mechanical strength than its counterpart, with the same relative density almost two-folds higher in the compressive response. However, the O-surface structure recorded more excellent energy absorption and flexible behavior under compression. Additionally, the compression behavior of the O-surface structure was progressive from top to bottom. In contrast, the sea urchin structure was collapsed randomly due to originated cracks from unit cells’ centers with local buckling effects. Moreover, the buckling direction of structures in long columns was also affected by keeping the relative density constant. Finally, based on specific strength, the O-surface structure exhibited 16-folds higher specific strength than the sea urchin structure. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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18 pages, 1551 KiB

Open AccessEditor’s ChoiceArticle

Study of Optimal Cam Design of Dual-Axle Spring-Loaded Camming Device

by David Rybansky, Martin Sotola, Pavel Marsalek, Zdenek Poruba and Martin Fusek

Materials 2021, 14(8), 1940; https://doi.org/10.3390/ma14081940 - 13 Apr 2021

Cited by 8 | Viewed by 3814

Abstract

The spring-loaded camming device (SLCD), also known as “friend”, is a simple mechanism used to ensure the safety of the climber through fall prevention. SLCD consists of two pairs of opposing cams rotating separately, with one (single-axle SLCD) or two (dual-axle SLCD) pins [...] Read more.

The spring-loaded camming device (SLCD), also known as “friend”, is a simple mechanism used to ensure the safety of the climber through fall prevention. SLCD consists of two pairs of opposing cams rotating separately, with one (single-axle SLCD) or two (dual-axle SLCD) pins connecting the opposing cams, a stem, connected to the pins, providing the attachment of the climbing rope, springs, which simultaneously push cams to a fully expanded position, and an operating element controlling the cam position. The expansion of cams is thus adaptable to allow insertion or removal of the device into/from a rock crack. While the pins, stem, operating element, and springs can be considered optimal, the (especially internal) shape of the cam allows space for improvement, especially where the weight is concerned. This paper focuses on optimizing the internal shape of the dual-axle SLCD cam from the perspective of the weight/stiffness trade-off. For this purpose, two computational models are designed and multi-step topology optimization (TOP) are performed. From the computational models’ point of view, SLCD is considered symmetric and only one cam is optimized and smoothened using parametric curves. Finally, the load-bearing capacity of the new cam design is analyzed. This work is based on practical industry requirements, and the obtained results will be reflected in a new commercial design of SLCD. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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18 pages, 10340 KiB

Open AccessArticle

The Analysis of the Morphology of the Saddle-Shaped Bronze Chips Briquettes Produced in the Roller Press

by Michał Bembenek, Janusz Krawczyk, Łukasz Frocisz and Tomasz Śleboda

Materials 2021, 14(6), 1455; https://doi.org/10.3390/ma14061455 - 16 Mar 2021

Cited by 8 | Viewed by 1926

Abstract

This paper presents the results of the investigations of the properties of saddle-shaped copper alloy chips briquettes produced in a roller press. The physical and mechanical properties of the investigated briquettes were examined on their external surfaces as well as on their cross-sections. [...] Read more.

This paper presents the results of the investigations of the properties of saddle-shaped copper alloy chips briquettes produced in a roller press. The physical and mechanical properties of the investigated briquettes were examined on their external surfaces as well as on their cross-sections. The density, chemical composition, microstructure analysis obtained with a 3D and scanning microscope, surface roughness and hardness of the obtained briquettes were investigated. The research proved the differentiation of the physical and mechanical properties of briquettes depending on the investigated area of their surface. The analysis of changes in the porosity of briquettes on their cross-section showed zones of various densification levels. This research expands the knowledge of the processes taking place during the compaction and consolidation of granular materials in roller presses as well as the knowledge concerning designing the geometry of forming tools. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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14 pages, 5626 KiB

Open AccessEditor’s ChoiceArticle

A Numerical Study of Geometry’s Impact on the Thermal and Mechanical Properties of Periodic Surface Structures

by Elzbieta Gawronska and Robert Dyja

Materials 2021, 14(2), 427; https://doi.org/10.3390/ma14020427 - 16 Jan 2021

Cited by 16 | Viewed by 2809

Abstract

The paper focuses on thermal and mechanical analysis of Periodic Surface Structure (PSS). PSS is a continuous surface with a specific topology that is mathematically formulated by geometric factors. Cubic P-surface (“primitive”), D-surface (“diamond”), and G-surface (“gyroid”) structures were simulated under load and [...] Read more.

The paper focuses on thermal and mechanical analysis of Periodic Surface Structure (PSS). PSS is a continuous surface with a specific topology that is mathematically formulated by geometric factors. Cubic P-surface (“primitive”), D-surface (“diamond”), and G-surface (“gyroid”) structures were simulated under load and heat transport using a numerical approach. We conducted our study by solving the stress and heat equations using the Finite Element Method (FEM). We achieved results using our software module, which generates PSS and simulates stress and temperature distribution. The stress model defined by dependence between stress and strain, gained from an experiment, and correlation of strain and displacement, gained from geometric conditions, was used in numerical experiments. The influence of geometric factors on the thermal and mechanical behavior of PSS was qualitatively determined. We showed decreasing effective stress values with an increased number of cells in the cubic domain for concerned PSS. It is important, because the increase in the number of cells does not increase the structure’s volume. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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16 pages, 6547 KiB

Open AccessArticle

Experimental Study on Influence of Curing Time on Strength Behavior of SLA-Printed Samples Loaded with Different Strain Rates

by Danuta Miedzińska, Roman Gieleta and Arkadiusz Popławski

Materials 2020, 13(24), 5825; https://doi.org/10.3390/ma13245825 - 21 Dec 2020

Cited by 32 | Viewed by 3541

Abstract

Stereolithography (SLA) is an additive manufacturing process based on the photocuring of resins with the use of UV light. The printed samples can be used not only for the visualization of structures, but also to develop elements of real constructions. In the study, [...] Read more.

Stereolithography (SLA) is an additive manufacturing process based on the photocuring of resins with the use of UV light. The printed samples can be used not only for the visualization of structures, but also to develop elements of real constructions. In the study, SLA-printed samples made of Formlabs’ Durable Resin were tested in static, dynamic, and Hopkinson’s bar tests. The recommended UV and heat curing time for this resin is 60 min for each process. For the tests, 5-minute and 30-min curing times were also considered. The obtained stress-strain curves were compared. The resin showed a difference in response to the strain rate effect and a curing time influence was noticed. For the static tests, the post-curing time had the greatest effect with a very small standard deviation. For the dynamic tests, similar dependencies were observed but with a greater standard deviation. The tests at very high strain rates were associated with a much greater level of difficulty in execution, recording, and signal analyzing, and the influence of the exposure time on the mechanical properties was not straightforward. The tested resin showed strengthening with increases in the strain rate as well as in the curing time. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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20 pages, 49498 KiB

Open AccessArticle

Influence of Different Strain Hardening Models on the Behavior of Materials in the Elastic–Plastic Regime under Cyclic Loading

by Peter Sivák, Peter Frankovský, Ingrid Delyová, Jozef Bocko, Ján Kostka and Barbara Schürger

Materials 2020, 13(23), 5323; https://doi.org/10.3390/ma13235323 - 24 Nov 2020

Cited by 5 | Viewed by 2322

Abstract

In exact analyses of bodies in the elastic–plastic regime, the behavior of the material above critical stress values plays a key role. In addition, under cyclic stress, important phenomena to be taken into account are the various types of hardening and the design [...] Read more.

In exact analyses of bodies in the elastic–plastic regime, the behavior of the material above critical stress values plays a key role. In addition, under cyclic stress, important phenomena to be taken into account are the various types of hardening and the design of the material or structure. In this process, it is important to define several groups of characteristics. These include, for instance, the initial area of plasticity or load which defines the interface between elastic and plastic deformation area. The characteristics also include the relevant law of plastic deformation which specifies the velocity direction of plastic deformation during plastic deformation. In the hardening condition, it is also important to determine the position, size and shape of the subsequent loading area. The elasto-plastic theory was used for the analysis of special compliant mechanisms that are applied for positioning of extremely precise members of the Compact Linear Collider (CLIC), e.g., cryomagnets, laser equipment, etc. Different types of deformation hardening were used to simulate the behavior of particular structural elements in the elastic–plastic regime. Obtained values of stresses and deformations may be used in further practical applications or as default values in other strain hardening model simulations. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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11 pages, 5382 KiB

Open AccessArticle

Magnetorheological Elastomer Stress Relaxation Behaviour during Compression: Experiment and Modelling

by Mateusz Kukla, Łukasz Warguła, Krzysztof Talaśka and Dominik Wojtkowiak

Materials 2020, 13(21), 4795; https://doi.org/10.3390/ma13214795 - 27 Oct 2020

Cited by 14 | Viewed by 2166

Abstract

Materials characterized by magnetorheological properties are non-classic engineering materials. A significant increase in the interest of the scientific community about this group of materials could be observed over the recent years. The results of research presented in this article are oriented on the [...] Read more.

Materials characterized by magnetorheological properties are non-classic engineering materials. A significant increase in the interest of the scientific community about this group of materials could be observed over the recent years. The results of research presented in this article are oriented on the examination of the said materials’ mechanical properties. Stress relaxation tests were carried out on cylindrical samples of magnetorheological elastomers loaded with compressive stress, for various values of magnetic induction (

B_{1}

= 0 mT,

B_{2}

= 32 mT,

B_{3}

= 48 mT, and

B_{4}

= 64 mT) and temperature (

T_{1}

= 25 °C,

T_{2}

= 30 °C, and

T_{3}

= 40 °C). The results of these tests indicate that the stiffness of the examined samples increased along with the increase of magnetic field induction, and decreased along with the increase of temperature. On this basis, it has been determined that: the biggest stress amplitude change, caused by the influence of magnetic field, was

σ_{0}^{Δ B}

= 12.7%, and the biggest stress amplitude change, caused by the influence of temperature, was

σ_{0}^{Δ T}

= 11.3%. As a result of applying a mathematical model, it was indicated that the stress relaxation in the examined magnetorheological elastomer, for the adopted time range (

t

= 3600 s), had a hyperbolic decline nature. The collected test results point to the examined materials being characterized by extensive rheological properties, which leads to the conclusion that it is necessary to conduct further tests in this area. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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11 pages, 4962 KiB

Open AccessArticle

Morphologies, Young’s Modulus and Resistivity of High Aspect Ratio Tungsten Nanowires

by Jianjun Gao, Jian Luo, Haibin Geng, Kai Cui, Zhilong Zhao and Lin Liu

Materials 2020, 13(17), 3749; https://doi.org/10.3390/ma13173749 - 25 Aug 2020

Cited by 5 | Viewed by 2598

Abstract

High aspect ratio tungsten nanowires have been prepared by selective dissolution of Nickel-aluminum-tungsten (NiAl−W) alloys which were directionally solidified at growth rates varying from 2 to 25 μm/s with a temperature gradient of 300 K·cm⁻¹. Young’s modulus and electrical resistivity of [...] Read more.

High aspect ratio tungsten nanowires have been prepared by selective dissolution of Nickel-aluminum-tungsten (NiAl−W) alloys which were directionally solidified at growth rates varying from 2 to 25 μm/s with a temperature gradient of 300 K·cm⁻¹. Young’s modulus and electrical resistivity of tungsten nanowires were measured by metallic mask template method. The results show that the tungsten nanowires with uniform diameter and high aspect ratio are well aligned. The length of tungsten nanowires increases with prolongation of etching time, and their length reaches 300 μm at 14 h. Young’s modulus of tungsten nanowires is estimated by Hertz and Sneddon models. The Sneddon model is proper for estimating the Young’s modulus, and the value of calculating Young’s modulus are 260–460 GPa which approach the value of bulk tungsten. The resistivity of tungsten nanowires is measured and fitted with Fuchs−Sondheimer (FS) + Mayadas−Shatzkes (MS) model. The fitting results show that the specific resistivity of W nanowires is a litter bigger than the bulk W, and its value decreases with decreasing diameter. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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Review

Jump to: Research

27 pages, 10182 KiB

Open AccessReview

Applications and Developments of Thermal Spray Coatings for the Iron and Steel Industry

by Surinder Singh, Christopher C. Berndt, R. K. Singh Raman, Harpreet Singh and Andrew S. M. Ang

Materials 2023, 16(2), 516; https://doi.org/10.3390/ma16020516 - 5 Jan 2023

Cited by 21 | Viewed by 6187

Abstract

The steel making processes involves extreme and harsh operating conditions; hence, the production hardware is exposed to degradation mechanisms under high temperature oxidation, erosion, wear, impact, and corrosive environments. These adverse factors affect the product quality and efficiency of the steel making industry, [...] Read more.

The steel making processes involves extreme and harsh operating conditions; hence, the production hardware is exposed to degradation mechanisms under high temperature oxidation, erosion, wear, impact, and corrosive environments. These adverse factors affect the product quality and efficiency of the steel making industry, which contributes to production downtime and maintenance costs. Thermal spray technologies that circumvent surface degradation mechanisms are also attractive for their environmental safety, effectiveness and ease of use. The need of thermal spray coatings and advancement in terms of materials and spray processes are reviewed in this article. Application and development of thermal spray coatings for steel making hardware from the molten metal processing stages such as electric arc and basic oxygen furnaces, through to continuous casting, annealing, and the galvanizing line; to the final shaping process such as cold and hot rolling of the steel strips are highlighted. Specifically, thermal spray feedstock materials and processes that have potential to replace hazardous hard chrome plating are discussed. It is projected that novel coating solutions will be incorporated as awareness and acceptance of thermal spray technology grows in the steel making sectors, which will improve the productivity of the industry. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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24 pages, 3155 KiB

Open AccessReview

The Joining of Copper to Stainless Steel by Solid-State Welding Processes: A Review

by Gaurang R. Joshi, Vishvesh J. Badheka, Raghavendra S. Darji, Ankit D. Oza, Vivek J. Pathak, Dumitru Doru Burduhos-Nergis, Diana Petronela Burduhos-Nergis, Gautam Narwade and Gopinath Thirunavukarasu

Materials 2022, 15(20), 7234; https://doi.org/10.3390/ma15207234 - 17 Oct 2022

Cited by 16 | Viewed by 4401

Abstract

Joining immiscible materials such as copper and stainless steel together is a significant concern due to distinct mechanical and metallurgical properties across the joint line, such as melting points, the coefficient of linear thermal expansion, and thermal conductivity. The joint properties of copper [...] Read more.

Joining immiscible materials such as copper and stainless steel together is a significant concern due to distinct mechanical and metallurgical properties across the joint line, such as melting points, the coefficient of linear thermal expansion, and thermal conductivity. The joint properties of copper to stainless steel welds are in great demand for various mechanical components of the international thermonuclear experimental reactor, ultra-high vacuum system, plan wave linear-accelerator or linac structure, and heat exchanger. These dissimilar-metals joints offer excellent flexibility in design and production, leading to a robust structure for many cutting-edge applications. Hence, the present article reviews the copper to stainless steel joining mechanism under different solid-state processing conditions. The present understanding says that defect-free strong joints between the dissimilar metals are systematically possible. Apart from this understanding, the authors have identified and highlighted the gaps in the research exploration to date. Moreover, a sustainable methodology to achieve a desirable weld of copper to stainless steel depends on favorable processing conditions. Full article

(This article belongs to the Special Issue Manufacturing and Mechanics of Materials)

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