Materials

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15 pages, 6012 KiB

Open AccessArticle

Numerical and Experimental Modal Analysis of a Gyroid Inconel 718 Structure for Stiffness Specification in the Design of Load-Bearing Components

by Katarina Monkova, Sanjin Braut, Peter Pavol Monka, Ante Skoblar and Martin Pollák

Materials 2024, 17(14), 3595; https://doi.org/10.3390/ma17143595 - 21 Jul 2024

Viewed by 767

Abstract

The study aims to investigate the modal properties of a 60 × 70 × 80 mm gyroid structure made of Inconel 718 with 67.5% porosity. The geometry model for sample production was created using the software PTC Creo, whereas the geometry model for [...] Read more.

The study aims to investigate the modal properties of a 60 × 70 × 80 mm gyroid structure made of Inconel 718 with 67.5% porosity. The geometry model for sample production was created using the software PTC Creo, whereas the geometry model for numerical analysis was created using the Python application ScaffoldStructures. FE analysis was performed using ANSYS 2024 R1 software. Free boundary conditions were used in experimental modal analysis to ensure feasibility. The analysis identified the first four natural frequencies ranging from 10 to 16 kHz. The results revealed that the first natural frequency corresponds to the first torsional frequency about the Z axis, the second to the first flexural mode in the XZ plane, the third to the first bending mode in the YZ plane, and the fourth to the first torsional mode about the X axis. Small differences between the results of numerical and experimental modal analysis can be attributed to geometric errors in the manufactured sample, careless removal from the platform, and due to reduction in the complexity of the numerical FE model. Employing modal analysis of a component, the stiffness of a lightweight component can be revealed. In the case of the sample with the cellular structure of gyroid type, relatively high stiffness regarding the material savings was identified, which can be advantageously used in many applications. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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20 pages, 7417 KiB

Open AccessArticle

Facile-Solution-Processed Silicon Nanofibers Formed on Recycled Cotton Nonwovens as Multifunctional Porous Sustainable Materials

by Muhammad Shoaib, Hafsa Jamshaid, Rajesh Kumar Mishra, Mumtaz Ali, Vijay Chandan, Viktor Kolar, Shabnam Nazari, Akshat TM, Petr Jirku, Miroslav Muller and Tatiana Alexiou Ivanova

Materials 2024, 17(2), 412; https://doi.org/10.3390/ma17020412 - 14 Jan 2024

Viewed by 1694

Abstract

Limited efficiency, lower durability, moisture absorbance, and pest/fungal/bacterial interaction/growth are the major issues relating to porous nonwovens used for acoustic and thermal insulation in buildings. This research investigated porous nonwoven textiles composed of recycled cotton waste (CW) fibers, with a specific emphasis on [...] Read more.

Limited efficiency, lower durability, moisture absorbance, and pest/fungal/bacterial interaction/growth are the major issues relating to porous nonwovens used for acoustic and thermal insulation in buildings. This research investigated porous nonwoven textiles composed of recycled cotton waste (CW) fibers, with a specific emphasis on the above-mentioned problems using the treatment of silicon coating and formation of nanofibers via facile-solution processing. The findings revealed that the use of an economic and eco-friendly superhydrophobic (contact angle higher than 150°) modification of porous nonwovens with silicon nanofibers significantly enhanced their intrinsic characteristics. Notable improvements in their compactness/density and a substantial change in micro porosity were observed after a nanofiber network was formed on the nonwoven material. This optimized sample exhibited a superior performance in terms of stiffness, surpassing the untreated samples by 25–60%. Additionally, an significant enhancement in tear strength was observed, surpassing the untreated samples with an impressive margin of 70–90%. Moreover, the nanofibrous network of silicon fibers on cotton waste (CW) showed significant augmentation in heat resistance ranging from 7% to 24% and remarkable sound absorption capabilities. In terms of sound absorption, the samples exhibited a performance comparable to the commercial standard material and outperformed the untreated samples by 20% to 35%. Enhancing the micro-roughness of fabric via silicon nanofibers induced an efficient resistance to water absorption and led to the development of inherent self-cleaning characteristics. The antibacterial capabilities observed in the optimized sample were due to its superhydrophobic nature. These characteristics suggest that the proposed nano fiber-treated nonwoven fabric is ideal for multifunctional applications, having features like enhanced moisture resistance, pest resistance, thermal insulation, and sound absorption which are essential for wall covers in housing. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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16 pages, 6909 KiB

Open AccessArticle

Effect of Crosshead Speed and Volume Ratio on Compressive Mechanical Properties of Mono- and Double-Gyroid Structures Made of Inconel 718

by Katarina Monkova, Peter Pavol Monka, George A. Pantazopoulos, Anagnostis I. Toulfatzis, Anna Šmeringaiová, Jozef Török and Sofia Papadopoulou

Materials 2023, 16(14), 4973; https://doi.org/10.3390/ma16144973 - 12 Jul 2023

Cited by 2 | Viewed by 1552

Abstract

The current development of additive technologies brings not only new possibilities but also new challenges. One of them is the use of regular cellular materials in various components and constructions so that they fully utilize the potential of porous structures and their advantages [...] Read more.

The current development of additive technologies brings not only new possibilities but also new challenges. One of them is the use of regular cellular materials in various components and constructions so that they fully utilize the potential of porous structures and their advantages related to weight reduction and material-saving while maintaining the required safety and operational reliability of devices containing such components. It is therefore very important to know the properties of such materials and their behavior under different types of loads. The article deals with the investigation of the mechanical properties of porous structures made by the Direct Metal Laser Sintering (DMLS) of Inconel 718. Two types of basic cell topology, mono-structure Gyroid (G) and double-structure Gyroid + Gyroid (GG), with material volume ratios of 10, 15 and 20 %, were studied within our research to compare their properties under quasi-static compressive loading. The testing procedure was performed at ambient temperature with a servo-hydraulic testing machine at three different crosshead testing speeds. The recorded data were processed, while the stress–strain curves were plotted, and Young’s modulus, the yield strength Re_0.2, and the stress at the first peak of the local maximum σ_LocMax were identified. The results showed the best behavior under compression load among the studied structures displayed by mono-structure Gyroid at 10 %. At the same time, it can be concluded that the wall thickness of the structure plays an important role in the compressive properties but on the other hand, crosshead speed doesn´t influence results significantly. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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21 pages, 24809 KiB

Open AccessArticle

Evaluation of Mechanical Properties and Filler Interaction in the Field of SLA Polymeric Additive Manufacturing

by Petr Jirků, Jiří Urban, Miroslav Müller, Viktor Kolář, Vijay Chandan, Jaroslava Svobodová, Rajesh Kumar Mishra and Hafsa Jamshaid

Materials 2023, 16(14), 4955; https://doi.org/10.3390/ma16144955 - 12 Jul 2023

Cited by 2 | Viewed by 1670

Abstract

The paper deals with research focused on the use of fillers in the field of polymeric materials produced by additive technology SLA (stereolithography). The aim of the research is to evaluate 3D printing parameters, the mechanical properties (tensile strength, hardness), and the interaction [...] Read more.

The paper deals with research focused on the use of fillers in the field of polymeric materials produced by additive technology SLA (stereolithography). The aim of the research is to evaluate 3D printing parameters, the mechanical properties (tensile strength, hardness), and the interaction of individual phases (polymer matrix and filler) in composite materials using SEM analysis. The tested fillers were cotton flakes and ground carbon fibres in different proportions. For the photosensitive resins, the use of cotton flakes as filler was found to have a positive effect on the mechanical properties not only under static but also under cyclic loading, which is a common cause of material failure in practice. The cyclic stress reference value was set at an amplitude of 5–50% of the maximum force required to break the pure resin in a static tensile test. A positive effect of fillers on the cyclic stress life of materials was demonstrated. The service life of pure resin was only 168 ± 29 cycles. The service life of materials with fillers increased to approximately 400 to 540 cycles for carbon fibre-based fillers and nearly 1000 cycles for cotton flake-based fillers, respectively. In this paper, new composite materials suitable for the use of SLA additive manufacturing techniques are presented. Research demonstrated the possibilities of adding cotton-based fillers in low-cost, commercially available resins. Furthermore, the importance of material research under cyclic loading was demonstrated. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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23 pages, 6892 KiB

Open AccessArticle

Numerical and Experimental Analysis of Mechanical Properties in Hybrid Epoxy–Basalt Composites Partially Reinforced with Cellulosic Fillers

by Vijay Chandan, Rajesh Kumar Mishra, Viktor Kolář, Petr Jirků, Miroslav Müller and Hafsa Jamshaid

Materials 2023, 16(14), 4898; https://doi.org/10.3390/ma16144898 - 8 Jul 2023

Cited by 2 | Viewed by 1340

Abstract

The current work is focused on numerical and experimental studies of woven fabric composites modified by hybridisation with biological (cellulosic) filler materials. The mechanical performance of the composites is characterized under tensile, bending and impact loads and the effect of hybridisation is observed [...] Read more.

The current work is focused on numerical and experimental studies of woven fabric composites modified by hybridisation with biological (cellulosic) filler materials. The mechanical performance of the composites is characterized under tensile, bending and impact loads and the effect of hybridisation is observed with respect to pure and nonhybrid composites. Numerical models are developed using computational tools to predict mechanical performance under tensile loading. The computational prediction results are compared and validated with relevant experimental results. This research is aimed at understanding the mechanical performance of basalt–epoxy composites partially reinforced with micro-/nano-sized bio-fillers from cellulose and intended for various application areas. Different weave structures, e.g., plain, twill, matt, etc., were investigated with respect to the mechanical properties of the hybrid composites. The effects of hybridizing with cellulose particles and different weave patterns of the basalt fabric are studied. In general, the use of high-strength fibres such as basalt along with cellulosic fillers representing up to 3% of the total weight improves the mechanical performance of the hybrid structures. The thermomechanical performance of the hybrid composites improved significantly by using basalt fabric as well as by addition of 3% weight of cellulosic fillers. Results reveal the advantages of hybridisation and the inclusion of natural cellulosic fillers in the hybrid composite structures. The material developed is suitable for high-end applications in components for construction that demand advanced mechanical and thermomechanical performance. Furthermore, the inclusion of biodegradable fillers fulfills the objectives of sustainable and ecological construction materials. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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15 pages, 4327 KiB

Open AccessArticle

Finite Element Analysis of Different Osseocartilaginous Reconstruction Techniques in Animal Model Knees

by Cosmin Cosma, Dragos Apostu, Cristian Vilau, Alexandru Popan, Daniel Oltean-Dan, Nicolae Balc, Gheorghe Tomoaie and Horea Benea

Materials 2023, 16(7), 2546; https://doi.org/10.3390/ma16072546 - 23 Mar 2023

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Abstract

Lesions of the articular cartilage are frequent in all age populations and lead to functional impairment. Multiple surgical techniques have failed to provide an effective method for cartilage repair. The aim of our research was to evaluate the effect of two different compression [...] Read more.

Lesions of the articular cartilage are frequent in all age populations and lead to functional impairment. Multiple surgical techniques have failed to provide an effective method for cartilage repair. The aim of our research was to evaluate the effect of two different compression forces on three types of cartilage repair using finite element analysis (FEA). Initially, an in vivo study was performed on sheep. The in vivo study was prepared as following: Case 0—control group, without cartilage lesion; Case 1—cartilage lesion treated with macro-porous collagen implants; Case 2—cartilage lesion treated with collagen implants impregnated with bone marrow concentrate (BMC); Case 3—cartilage lesion treated with collagen implants impregnated with adipose-derived stem cells (ASC). Using the computed tomography (CT) data, virtual femur-cartilage-tibia joints were created for each Case. The study showed better results in bone changes when using porous collagen implants impregnated with BMC or ASC stem cells for the treatment of osseocartilaginous defects compared with untreated macro-porous implant. After 7 months postoperative, the presence of un-resorbed collagen influences the von Mises stress distribution, total deformation, and displacement on the Z axis. The BMC treatment was superior to ASC cells in bone tissue morphology, resembling the biomechanics of the control group in all FEA simulations. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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19 pages, 3959 KiB

Open AccessArticle

SiOC Screens with Aligned and Adjustable Pore Structure for Screen Channel Liquid Acquisition Device

by Pedro Henrique da Rosa Braun, Prithvi Shukla, Kurosch Rezwan, Michael Dreyer and Michaela Wilhelm

Materials 2023, 16(3), 1063; https://doi.org/10.3390/ma16031063 - 25 Jan 2023

Viewed by 1564

Abstract

The development of porous ceramic screens with high chemical stability, low density, and thermal conductivity can lead to promising screen channel liquid acquisition devices (SC-LADs) for propellant management under microgravity conditions in the future. Therefore, SiOC screens with aligned pores were fabricated via [...] Read more.

The development of porous ceramic screens with high chemical stability, low density, and thermal conductivity can lead to promising screen channel liquid acquisition devices (SC-LADs) for propellant management under microgravity conditions in the future. Therefore, SiOC screens with aligned pores were fabricated via freeze-casting and applied as a SC-LAD. The pore window sizes and open porosity varied from 6 µm to 43 µm and 65% or 79%, depending on the freezing temperature or the solid loading, respectively. The pore window size distributions and bubble point tests indicate crack-free screens. On the one hand, SC-LADs with an open porosity of 79% removed gas-free liquid up to a volumetric flow rate of 4 mL s⁻¹. On the other hand, SC-LADs with an open porosity of 65% were limited to 2 mL s⁻¹ as the pressure drop across these screens was relatively higher. SC-LADs with the same open porosity but smaller pore window sizes showed a higher pressure drop across the screen and bubble ingestion at higher values of effective screen area when increasing the applied removal volumetric flow rate. The removed liquid from the SC-LADs was particle-free, thus representing a potential for applications in a harsh chemical environment or broad-range temperatures. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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13 pages, 14032 KiB

Open AccessArticle

Microstructure and Properties of Hollow Octet Nickel Lattice Materials

by Peng Zhao, Deqing Huang, Yongfu Zhang, Hongmei Zhang and Weiwei Chen

Materials 2022, 15(23), 8417; https://doi.org/10.3390/ma15238417 - 25 Nov 2022

Cited by 4 | Viewed by 1521

Abstract

In this study, electroless nickel plating and electrodeposition were used to deposit thin films on the polymer lattice template prepared by 3D printing, then seven Octet hollow nickel lattice materials with different structural parameters were synthesized by etching process at the expense of [...] Read more.

In this study, electroless nickel plating and electrodeposition were used to deposit thin films on the polymer lattice template prepared by 3D printing, then seven Octet hollow nickel lattice materials with different structural parameters were synthesized by etching process at the expense of the polymer backbone. The microstructure and properties of the Octet structure nickel lattice were characterized by X-ray diffraction, Electron backscattering diffraction and transmission electron microscopy. According to the results, the average grain size of the electrodeposition Ni lattice material was 429 nm, and (001) weak texture was found along the direction of the film deposition. The lattice deformation mode changed with the increase of the lattice length-to-diameter ratio, and it shifted from the lattice deformation layer-by-layer and the overall deformation to the shear deformation in the 45° direction. The strength, modulus and energy absorption properties of the Octet lattice increased with the density, and they were exponentially related to density. In the relative density range of 0.7~5%, Octet hollow Ni lattices with the same density conditions but different structural parameters showed similar compressive strength and elasticity modulus; the energy absorption capacity, however, was weakened as the length-to-diameter ratio increased. Full article

(This article belongs to the Special Issue Preparation and Application of Regularly Structured Porous Materials)

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