Research

14 pages, 6991 KiB

Open AccessArticle

A Vibration Analysis of the Rubber Inertial Dampers Used in Electrical Vehicles

by Calin Itu, Sorin Vlase and Marin Marin

Polymers 2022, 14(5), 953; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14050953 - 27 Feb 2022

Cited by 2 | Viewed by 2200

The development of electric vehicle manufacturing, which is considered a useful new popular propulsion system, has major design differences compared to conventional vehicles. This requires a reconsideration of the main components of vehicles and an analysis of them to determine the optimal design [...] Read more.

The development of electric vehicle manufacturing, which is considered a useful new popular propulsion system, has major design differences compared to conventional vehicles. This requires a reconsideration of the main components of vehicles and an analysis of them to determine the optimal design and solutions for the new models of cars. Among the many systems that need to be reconsidered is the suspension. A cheaper solution for reducing the car’s vibrations is suspension where the damping is ensured by elastic rubber elements, which are very simple, as they have significant structural damping and a much lower price than the classic solution. The main advantage of this solution is the simplicity. The paper presents and analyzes such an element, analyzing the vibrations of this element and the way in which inertial masses (metal spheres) inserted into the volume of the rubber influence the behavior of this element. The transmissibility of such an element, and how the number of balls and the level of structural damping influences this property, is also analyzed. The results suggest possible applications in the automotive industry. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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11 pages, 2456 KiB

Open AccessArticle

Fire Retardancy, Water Absorption, and Viscoelasticity of Borated Wood—Polycarbonate Biocomposites

by Jingfa Zhang, Ahmed Koubaa, Dan Xing, François Godard, Peng Li, Yubo Tao, Xiang-Ming Wang and Haigang Wang

Polymers 2021, 13(14), 2234; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13142234 - 07 Jul 2021

Cited by 1 | Viewed by 2146

Abstract

Demand for high-performance biocomposites is increasing due to their ease of processing, low environmental impact, and in-service performance. This study investigated the effect of boric acid modification of wood flour on polycarbonate (PC) wood composites’ thermal stability, fire retardancy, water absorption, and creep [...] Read more.

Demand for high-performance biocomposites is increasing due to their ease of processing, low environmental impact, and in-service performance. This study investigated the effect of boric acid modification of wood flour on polycarbonate (PC) wood composites’ thermal stability, fire retardancy, water absorption, and creep behavior. The composites’ fire retardancy increased with increasing wood flour content, and their char residue increased by 102.3% compared to that of pure PC. However, the water absorption of the resulting composites increased due to the hydroxyl groups of the wood flour. Wood flour also improved the composites’ anti-creep properties. The excellent fire retardancy and anti-creep properties of wood–PC composites expand their use in the construction sector. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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12 pages, 2543 KiB

Open AccessArticle

Scale-Up of Biosynthesis Process of Bacterial Nanocellulose

by Nadezhda A. Shavyrkina, Vera V. Budaeva, Ekaterina A. Skiba, Galina F. Mironova, Nikolay V. Bychin, Yulia A. Gismatulina, Ekaterina I. Kashcheyeva, Anastasia E. Sitnikova, Aleksei I. Shilov, Pavel S. Kuznetsov and Gennady V. Sakovich

Polymers 2021, 13(12), 1920; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13121920 - 09 Jun 2021

Cited by 8 | Viewed by 2433

Abstract

Bacterial nanocellulose (BNC) is a unique product of microbiological synthesis, having a lot of applications among which the most important is biomedicine. Objective complexities in scaling up the biosynthesis of BNC are associated with the nature of microbial producers for which BNC is [...] Read more.

Bacterial nanocellulose (BNC) is a unique product of microbiological synthesis, having a lot of applications among which the most important is biomedicine. Objective complexities in scaling up the biosynthesis of BNC are associated with the nature of microbial producers for which BNC is not the target metabolite, therefore biosynthesis lasts long, with the BNC yield being small. Thus, the BNC scale-up problem has not yet been overcome. Here we performed biosynthesis of three scaled sheets of BNC (each having a surface area of 29,400 cm², a container volume of 441 L, and a nutrient medium volume of 260 L and characterized them. The static biosynthesis of BNC in a semisynthetic nutrient medium was scaled up using the Medusomyces gisevii Sa-12 symbiotic culture. The experiment was run in duplicate. The BNC pellicle was removed once from the nutrient medium in the first experiment and twice in the second experiment, in which case the inoculum and glucose were not additionally added to the medium. The resultant BNC sheets were characterized by scanning electron microscopy, capillary viscosimetry, infrared spectroscopy, thermomechanical and thermogravimetric analyses. When the nutrient medium was scaled up from 0.1 to 260 L, the elastic modulus of BNC samples increased tenfold and the degree of polymerization 2.5-fold. Besides, we demonstrated that scaled BNC sheets could be removed at least twice from one volume of the nutrient medium, with the yield and quality of BNC remaining the same. Consequently, the world’s largest BNC sheets 210 cm long and 140 cm wide, having a surface area of 29,400 cm² each (weighing 16.24 to 17.04 kg), have been obtained in which an adult with burns or vast wounds can easily be wrapped. The resultant sheets exhibit a typical architecture of cellulosic fibers that form a spatial 3D structure which refers to individual and extremely important characteristics of BNC. Here we thus demonstrated the scale-up of biosynthesis of BNC with improved properties, and this result was achieved by using the symbiotic culture. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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11 pages, 2290 KiB

Open AccessArticle

Effect of Printing Parameters on the Thermal and Mechanical Properties of 3D-Printed PLA and PETG, Using Fused Deposition Modeling

by Ming-Hsien Hsueh, Chao-Jung Lai, Shi-Hao Wang, Yu-Shan Zeng, Chia-Hsin Hsieh, Chieh-Yu Pan and Wen-Chen Huang

Polymers 2021, 13(11), 1758; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13111758 - 27 May 2021

Cited by 106 | Viewed by 8088

Abstract

Fused Deposition Modeling (FDM) can be used to manufacture any complex geometry and internal structures, and it has been widely applied in many industries, such as the biomedical, manufacturing, aerospace, automobile, industrial, and building industries. The purpose of this research is to characterize [...] Read more.

Fused Deposition Modeling (FDM) can be used to manufacture any complex geometry and internal structures, and it has been widely applied in many industries, such as the biomedical, manufacturing, aerospace, automobile, industrial, and building industries. The purpose of this research is to characterize the polylactic acid (PLA) and polyethylene terephthalate glycol (PETG) materials of FDM under four loading conditions (tension, compression, bending, and thermal deformation), in order to obtain data regarding different printing temperatures and speeds. The results indicated that PLA and PETG materials exhibit an obvious tensile and compression asymmetry. It was observed that the mechanical properties (tension, compression, and bending) of PLA and PETG are increased at higher printing temperatures, and that the effect of speed on PLA and PETG shows different results. In addition, the mechanical properties of PLA are greater than those of PETG, but the thermal deformation is the opposite. The above results will be a great help for researchers who are working with polymers and FDM technology to achieve sustainability. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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16 pages, 2582 KiB

Open AccessArticle

Investigation on the Thermoforming of Pmsq-Hdpe for the Manufacture of a NACA Profile of Small Dimensions

by Erchiqui Fouad, Abdessamad Baatti, Karima Ben Hamou, Hamid Kaddami, Mhamed Souli and Abdellatif Imad

Polymers 2021, 13(10), 1622; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13101622 - 17 May 2021

Viewed by 1681

Abstract

Unmanned aerial vehicles (UAVs) or drones are attracting increasing interest in the aviation industry, both for military and civilian applications. The materials used so far in the manufacture of UAVs are wood, plastic, aluminum and carbon fiber. In this regard, a new family [...] Read more.

Unmanned aerial vehicles (UAVs) or drones are attracting increasing interest in the aviation industry, both for military and civilian applications. The materials used so far in the manufacture of UAVs are wood, plastic, aluminum and carbon fiber. In this regard, a new family of high-density polyethylene (HDPE) nanocomposites reinforced with polymethylsilsesquioxane nanoparticles (PMSQ), with mechanical performances significantly superior to those of pure HPDE, has been prepared by a fusion-combination process. Their viscoelastic properties were determined by oscillatory shear tests and their viscoelastic behavior characterized by the Lodge integral model. Then, the Lagrangian formulation and the membrane theory assumption were used in the explicit implementation of the dynamic finite element formulation. For the forming phase, we considered the thermodynamic approach to express the external work in terms of closed volume. In terms of von Mises stress distribution and thickness in the blade, the results indicate that HDPE-PMSQ behaves like virgin HDPE. Furthermore, its materials, for all intents and purposes, require the same amount of energy to form as HDPE. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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15 pages, 5091 KiB

Open AccessEditor’s ChoiceArticle

Mechanical Properties, Wettability and Thermal Degradation of HDPE/Birch Fiber Composite

by Agbelenko Koffi, Fayçal Mijiyawa, Demagna Koffi, Fouad Erchiqui and Lotfi Toubal

Polymers 2021, 13(9), 1459; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13091459 - 30 Apr 2021

Cited by 13 | Viewed by 2558

Abstract

Wood–plastic composites have emerged and represent an alternative to conventional composites reinforced with synthetic carbon fiber or glass fiber–polymer. A wide variety of wood fibers are used in WPCs including birch fiber. Birch is a common hardwood tree that grows in cool areas [...] Read more.

Wood–plastic composites have emerged and represent an alternative to conventional composites reinforced with synthetic carbon fiber or glass fiber–polymer. A wide variety of wood fibers are used in WPCs including birch fiber. Birch is a common hardwood tree that grows in cool areas such as the province of Quebec, Canada. The effect of the filler proportion on the mechanical properties, wettability, and thermal degradation of high-density polyethylene/birch fiber composite was studied. High-density polyethylene, birch fiber and maleic anhydride polyethylene as coupling agent were mixed and pressed to obtain test specimens. Tensile and flexural tests, scanning electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetry analysis and surface energy measurement were carried out. The tensile elastic modulus increased by 210% as the fiber content reached 50% by weight while the flexural modulus increased by 236%. The water droplet contact angle always exceeded 90°, meaning that the material remained hydrophobic. The thermal decomposition mass loss increased proportional with the percentage of fiber, which degraded at a lower temperature than the HDPE did. Both the storage modulus and the loss modulus increased with the proportion of fiber. Based on differential scanning calorimetry, neither the fiber proportion nor the coupling agent proportion affected the material melting temperature. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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16 pages, 4547 KiB

Open AccessArticle

Investigation of the Ballistic Performance of GFRP Laminate under 150 m/s High-Velocity Impact: Simulation and Experiment

by Fengyan Chen, Yong Peng, Xuanzhen Chen, Kui Wang, Zhixiang Liu and Chao Chen

Polymers 2021, 13(4), 604; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13040604 - 17 Feb 2021

Cited by 5 | Viewed by 2179

Abstract

The ballistic resistance of GFRP laminates subjected to high-velocity impact was studied. Based on the damage situation of GFRP laminate observed from the single-stage gas gun testing, the three-dimensional (3D) model combining strain rate effect and Hashin failure criterion was established, and the [...] Read more.

The ballistic resistance of GFRP laminates subjected to high-velocity impact was studied. Based on the damage situation of GFRP laminate observed from the single-stage gas gun testing, the three-dimensional (3D) model combining strain rate effect and Hashin failure criterion was established, and the result presented good agreement between the simulation and experiment. Three factors, including layer angle, stacking sequence and proportion of different layer angles, were taken into consideration in the models. An orthogonal test method was used for the analysis, which can reduce the number of simulations effectively without sacrificing the accuracy of the result. The result indicated a correlation between the ballistic resistance and layouts of GFRP laminates, on which the stacking sequence contributed stronger influence. What was more, the laminate with layer angles 0°/90° and ±45° presented greater ballistic resistance than the other angle pairs, and adopting an equal proportion of different layer angles is helpful for GFRP laminates to resist impact as well. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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16 pages, 8555 KiB

Open AccessArticle

Mechanical Properties of Additively Manufactured Thermoplastic Polyurethane (TPU) Material Affected by Various Processing Parameters

by Tao Xu, Wei Shen, Xiaoshan Lin and Yi Min Xie

Polymers 2020, 12(12), 3010; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12123010 - 16 Dec 2020

Cited by 42 | Viewed by 7063

Abstract

Thermoplastic polyurethane (TPU) is a polymer material that has high ductility, good biocompatibility and excellent abrasion resistance. These properties open a pathway to manufacturing functional TPU parts for applications in various fields such as aerospace engineering, medical devices and sports equipment. This study [...] Read more.

Thermoplastic polyurethane (TPU) is a polymer material that has high ductility, good biocompatibility and excellent abrasion resistance. These properties open a pathway to manufacturing functional TPU parts for applications in various fields such as aerospace engineering, medical devices and sports equipment. This study aims to investigate the mechanical properties of additively manufactured TPU material affected by three different processing parameters, including build orientation, mix ratio of the new and reused powders and post-processing. A series of material tests are conducted on TPU dumb-bell specimens. It is found that the mix ratio of the new powder is the most critical factor in improving the mechanical properties of the printed TPU parts. Compared to reused powder, new powder has better particle quality and thermal properties. Besides, build orientation is also a very important factor. TPU parts printed in flat and on-edge orientations show better tensile strength and deformability than those printed in upright orientation. In addition, post-processing is found to significantly enhance the deformability of TPU parts. Full article

(This article belongs to the Special Issue Mechanical Properties and Behavior of Polymer-Based Materials)

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