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  • Open Access

    ARTICLE

    Toddy Palm (Borassus Flabellifer) Fruit Fibre Bundles as Reinforcement in Polylactide (PLA) Composites: An Overview About Fibre and Composite Characteristics

    Nina Graupner1,*, Koranat Narkpiban2,5, Thiprada Poonsawat3, Porntip Tooptompong4, Jörg Müssig1

    Journal of Renewable Materials, Vol.7, No.8, pp. 693-711, 2019, DOI:10.32604/jrm.2019.06785

    Abstract Toddy palm fruit have an apparent density below 0.8 g/cm³ and offer an interesting lightweight construction potential in polylactide (PLA) composites reinforced with 37 mass-% fibres. Single fibre bundles show similar mechanical properties compared with coir: tensile strength of 240 MPa, Young´s modulus of 3.8 GPa and an elongation at break of 31%. However, density and diameter (~ 50 μm) of fruit fibre bundles are significantly lower. The compression moulded composites have a density of 0.9 g/cm³ and achieved an unnotched Charpy impact strength of 12 kJ/m², a tensile strength of 25 MPa, Young’s modulus of 1.9 GPa and an… More >

  • Open Access

    ARTICLE

    Reinforcement of Thermoplastic Starch Films with Cellulose Fibres Obtained from Rice and Coffee Husks

    Sofía Collazo-Bigliardi1,*, Rodrigo Ortega-Toro2, Amparo Chiralt Boix1

    Journal of Renewable Materials, Vol.6, No.6, pp. 599-610, 2018, DOI:10.32604/JRM.2018.00127

    Abstract Cellulosic fibres from coffee (CF) and rice (RF) husks have been obtained applying chemical treatments and characterized as to their microstructure and thermal behaviour. These materials have been incorporated into glycerol plasticised thermoplastic starch (TPS) films obtained by melt blending and compression moulding at 1 wt%, 5 wt% and 10 wt%. Microstructure, thermal behaviour and optical, tensile and barrier properties of the composites were analysed. Both kinds of micro-fibres improve the film stiffness while reduced the film stretchability. However, CF better maintained the film ductility at 1 and 5 wt%. A network of fine oriented fibres was observed on the… More >

  • Open Access

    ARTICLE

    Reinforced 2d Domain Analysis Using BEM and Regularized BEM/FEM Combination

    Alexandre S. Botta1, Wilson S. Venturini2

    CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.1, pp. 15-28, 2005, DOI:10.3970/cmes.2005.008.015

    Abstract In this work a regularized boundary-finite element combination is proposed to analyse 2D elastostatic solids reinforced by fibres. The boundary element is adopted to model the matrix behaviour, while finite elements model the embedded fibres. The debonding effects caused by the adherence loss between the two materials are also considered. A three-degree polynomial is adopted to approach the displacement field along the fibre elements, while linear approximations are used to represent the bonding forces between fibres and the matrix. The non-linear debonding model is governed by a loading function written in terms of the contact forces and the relative displacements.… More >

  • Open Access

    ARTICLE

    Multi-Inclusion Unit Cell Studies of Reinforcement Stresses and Particle Failure in Discontinuously Reinforced Ductile Matrix Composites

    H.J. Bohm¨ 1, W. Han1,2, A. Eckschlager1,3

    CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 5-20, 2004, DOI:10.3970/cmes.2004.005.005

    Abstract Three-dimensional periodic micromechanical models are used for studying the mechanical behavior of discontinuously reinforced ductile matrix composites. The models are based on unit cells that contain a number of randomly positioned and, where applicable, randomly oriented spherical, spheroidal or cylindrical reinforcements. The Finite Element method is used to resolve the microscale stress and strain fields and to predict the homogenized responses under overall uniaxial tensile loading in the elastic and elastoplastic regimes. Periodicity boundary conditions are employed in the analyses.\\ The main emphasis of the contribution is put on studying the microscale stresses in the reinforcements, which are evaluated in… More >

  • Open Access

    ARTICLE

    Supercritical Carbon Dioxide Treated Kenaf Bast Pulp Fiber Reinforcement in Epoxy Composite

    N. A. Sri Aprilia1, M. S. Nurul Atiqah2, Zhari Ismail3, C. Y. Loo2, Chaturbhuj K. Saurabh2, Rudi Dungani4, Abdul Khalil H.P.S2*

    Journal of Renewable Materials, Vol.5, No.5, pp. 380-387, 2017, DOI:10.7569/JRM.2017.634130

    Abstract Due to environmental concerns, green composites have become a highly researched material. In the present study, kenaf fiber was used as reinforcement in epoxy-based composite with weight fraction ranges from 0, 5, 10, and 15% (w/w of resin). The ratio of epoxy to hardener was 65:32.5. Prior to incorporation, kenaf bast fiber underwent Soda-AQ pulping followed by total chlorine-free bleaching (OAZP sequence). The obtained pulp was then subjected to supercritical carbon dioxide extraction (SCE) treatment. It was observed that epoxy composite with 10% of fiber loading demonstrated the highest mechanical properties with a tensile strength of 64 MPa, tensile modulus… More >

  • Open Access

    ARTICLE

    Synthesis and Reinforcement of Thermostable Polymers Using Renewable Resources

    Nicole Segura Salas1, Felipe Orozco Gutiérrez3, Luis Daniel Mora Murillo2, Yendry Corrales Ureña3, Shakira Johnson1, José Vega Baudrit3, Rodolfo Jesús González-Paz3*

    Journal of Renewable Materials, Vol.5, No.3-4, pp. 313-322, 2017, DOI:10.7569/JRM.2017.634122

    Abstract Vegetable oils are being used for the production of biodegradable polymers, opening new possibilities for the synthesis of greener materials that could compete in national markets with petroleum-based polymers. In this study, castor oil and a catalyst (cobalt[II] naphtenate as promotor and MEKP as initiator) from local stores and styrene in different ratios were used to produce thermostable polymers. The kinetics of the polymerization reaction was followed by infrared spectroscopy. A polymeric material was synthetized which presents good mechanical properties. Therefore, composites were produced using 1 wt% of microcellulose extracted from biomass waste as reinforcement or 1 wt% microsilica to… More >

  • Open Access

    ARTICLE

    Deep Q-Learning Based Computation Offloading Strategy for Mobile Edge Computing

    Yifei Wei1,*, Zhaoying Wang1, Da Guo1, F. Richard Yu2

    CMC-Computers, Materials & Continua, Vol.59, No.1, pp. 89-104, 2019, DOI:10.32604/cmc.2019.04836

    Abstract To reduce the transmission latency and mitigate the backhaul burden of the centralized cloud-based network services, the mobile edge computing (MEC) has been drawing increased attention from both industry and academia recently. This paper focuses on mobile users’ computation offloading problem in wireless cellular networks with mobile edge computing for the purpose of optimizing the computation offloading decision making policy. Since wireless network states and computing requests have stochastic properties and the environment’s dynamics are unknown, we use the model-free reinforcement learning (RL) framework to formulate and tackle the computation offloading problem. Each mobile user learns through interactions with the… More >

  • Open Access

    ARTICLE

    Interfacial Stresses Induced by a Point Heat Source in an Isotropic Plate with a Reinforced Elliptical Hole

    Ching Kong Chao1,2, Chin Kun Chen1, Fu Mo Chen3

    CMES-Computer Modeling in Engineering & Sciences, Vol.63, No.1, pp. 1-28, 2010, DOI:10.3970/cmes.2010.063.001

    Abstract A general analytical solution for a reinforced elliptical hole embedded in an infinite matrix subjected to a point heat source is provided in this paper. Based on the technique of conformal mapping and the method of analytical continuation in conjunction with the alternating technique, the general expressions of the temperature and stresses in the reinforcement layer and the matrix are derived explicitly in a series form. Some numerical results are provided to investigate the effects of the material combinations and geometric configurations on the interfacial stresses. The solution obtained can be treated as Green's functions which enable us to formulate… More >

  • Open Access

    ARTICLE

    Micromechanical analysis of aligned and randomly oriented whisker-/ short fiber-reinforced composites

    S.H. Pyo1, H.K. Lee1,2

    CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.3, pp. 271-306, 2009, DOI:10.3970/cmes.2009.040.271

    Abstract This paper presents a micromechanical approach for predicting the elastic and multi-level damage response of aligned and randomly oriented whisker-/ short fiber-reinforced composites. Based on a combination of Eshelby's micromechanics and the evolutionary imperfect interface approach, the effective elastic moduli of the composites are derived explicitly. The modified Eshelby's tensor for spheroidal inclusions with slightly weakened interface [Qu (1993b)] is extended in the present study to model whiskers or short fibers having mild or severe imperfect interfaces. Aligned and random orientations of spheroidal reinforcements are considered. A multi-level damage model in accordance with the Weibull's probabilistic function is then incorporated… More >

  • Open Access

    ARTICLE

    Effect of Reinforcement Corrosion Sediment Distribution Characteristics on Concrete Damage Behavior

    Fenghua Yuan1, Qing Zhang1,*, Xiaozhou Xia1

    CMC-Computers, Materials & Continua, Vol.58, No.3, pp. 777-793, 2019, DOI:10.32604/cmc.2019.04182

    Abstract Reinforcement corrosion directly affects the mechanical behavior of reinforced concrete structures. An electric corrosion test was conducted on a reinforced concrete test specimen, and a finite element model of the reinforcement corrosion damage was established. In addition, the damage behavior of reinforced concrete under different corrosion sediment distribution characteristics and different corrosion rates was studied. It was noted that when corrosion sediments are in a “semiellipse+semicircle” distribution, the results of numerical calculation are consistent with those obtained experimentally, reflecting the damage characteristics of reinforced concrete test specimens. Further, the results showed that the distribution characteristics of corrosion sediments greatly influence… More >

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