Makine Mühendisliği Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1944
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Book Part Citation - Scopus: 4Jute and Luffa Fibers: Physical, Acoustical, and Mechanical Properties(Elsevier, 2022) Yüce, Hüseyin; Genç, Garip; Körük, HasanIn this study, the physical, acoustical, and mechanical properties of jute and luffa fibers are presented. It should be noted that, although the main materials of jute and luffa fibers are cellulose, hemicellulose, and lignin, the mechanical properties of jute and luffa fibers and the acoustical properties of jute and fiber samples can be quite different. It is worth noting that jute fibers are bidirectional while luffa fibers are random-oriented. Furthermore, the diameters and lengths of these two fibers can be quite different. One problem with these natural fibers is that very different values for their diameter, length, and density have been reported in the literature. Therefore, the diameter, length, and density of a huge number of jute and luffa fibers were measured using precise equipment to determine their average values and deviations in this study. In addition to the results of these measurements, the results of a comprehensive literature review on the physical, acoustical, and mechanical properties of jute and fibers and their green samples (i.e., fiber samples without any resin) were presented in this study. © 2023 Elsevier Ltd. All rights reserved.Book Part Citation - Scopus: 3Effects of Machining on the Acoustic and Mechanical Properties of Jute and Luffa Biocomposites(Elsevier, 2023) Genç, Garip; Körük, HasanAfter their production, biocomposite structures do not always have the final shape or dimensions required for their purpose, hence, they need machining. However, the effects of machining on the acoustic and mechanical properties of many biocomposites are still not well known. The effects of machining on the acoustic and mechanical properties of jute and luffa biocomposites are revealed in this chapter. To do this, the sound absorption coefficients (or SACs) and transmission losses (or TLs) of jute and epoxy and luffa and epoxy composite samples, with and without a turning process, are determined using the impedance tube method. The loss factors and Young’s moduli of the jute and epoxy and luffa and epoxy composite samples, with and without a milling process, are identified using experimental and theoretical modal analyses. The results show that, when the samples are machined, the sound absorption coefficients reduce by 3%-7%, the transmission loss levels increase by 6-11dB, and the damping levels and Young’s moduli reduce by 0.1%-0.5% and 3%-4%, respectively. © 2023 Elsevier Ltd. All rights reserved.Book Part Citation - Scopus: 319 - Identification of the Elastic and Damping Properties of Jute and Luffa Fiber-Reinforced Biocomposites(Elsevier, 2022) Genç, Garip; Saygılı, Yusuf; Körük, Hasan; Şanlıtürk, Yusuf Kenan; Sanliturk, Kenan Y.Although there are many studies in the literature on the static mechanical properties of biomaterials such as tensile strength, the dynamic mechanical properties of biomaterials such as modal loss factors have not been investigated in detail. In this study, the Young’s moduli and damping (or loss factors) of some jute and luffa fiber-reinforced biocomposites are investigated. The effects of fiber/resin ratio and thickness on the mechanical properties of the jute and luffa composites are identified via an experimental approach. For this purpose, acoustic and structural frequency response functions of some homogeneous and hybrid jute and luffa composite plates with different fiber/resin ratios and thicknesses are measured. By analyzing the measured frequency response functions using the circle-fit method, the modal frequencies and loss factors of the homogeneous and hybrid composite plates are determined. By assuming that the homogeneous plates are isotropic, the same plates are modeled using the finite element method, and by comparing the experimental and theoretical natural frequencies, the elastic properties of the homogeneous plates are determined. In addition, the same homogeneous plates are modeled by considering an anisotropic material model, and the associated material properties are determined. By using the identified material properties, the finite element models of the hybrid composite plates are developed, and by comparing their experimental and theoretical natural frequencies, the identified elastic material properties are evaluated and validated.Article Citation - Scopus: 10Investigation of the Sound Absorption and Transmission Loss Performances of Green Homogenous and Hybrid Luffa and Jute Fiber Samples(King Mongkut’s University of Technology North Bangkok, 2021) Genç, Garip; Şanlıtürk, Kenan Y.; Körük, Hasan; Özcan, Ahmet CihanIn order to promote the use of natural fibers in noise and vibration applications, the properties of these structures should be fully identified. The sound absorption coefficients (SACs) and transmission losses (TLs) of green luffa fiber samples are thoroughly investigated and their acoustic performances are compared with the acoustic performances of green homogenous jute and hybrid jute/luffa fiber samples in this study. For this purpose, green homogenous luffa and jute fiber samples and their green hybrid fiber samples with different thicknesses (10, 20, 30, and 40 mm) are produced and their SACs and TLs are determined using the impedance tube method. First, the methods for the experimental identification of acoustic properties are presented and the variations in the measured acoustic properties are identified. After that, the effects of sample thickness on the acoustic performances of homogenous luffa as well as jute samples and their hybrid fiber samples as a function of frequency are explored. The thickness-dependent tendencies of the SACs and TLs of homogenous and hybrid luffa and jute fiber samples for low, medium and high frequency ranges are determined. Then, the acoustic performances of the homogenous and hybrid luffa and jute samples are compared and evaluated. The results and analyses for the acoustic properties of homogeneous luffa and jute fiber samples and their hybrid fiber samples for a variety of thicknesses and different frequencies presented here can be used to design homogenous as well as hybrid luffa and jute fiber structures in practical applications.Article Citation - WoS: 19Citation - Scopus: 26Jute and Luffa Fiber-Reinforced Biocomposites: Effects of Sample Thickness and Fiber/Resin Ratio on Sound Absorption and Transmission Loss Performance(Taylor & Francis, 2021) Şanlıtürk, Kenan Y.; Genç, Garip; Körük, Hasan; Özcan, Ahmet CihanThe acoustic properties of natural fiber-reinforced composites should be identified before using these materials in various engineering applications including sound and vibration isolation. This study investigates the effects of sample thickness and fiber/resin ratio on the acoustic performance of jute and luffa fiber-reinforced biocomposites. For this purpose, jute and luffa composite samples with different thicknesses and fiber/epoxy ratios are manufactured and their sound absorption coefficients (SACs) and transmission losses (TLs) are determined using impedance tube method. Thickness-dependent tendencies of the SACs and TLs of jute and luffa composites for low-, medium-, and high-frequency ranges are identified. The effect of fiber/epoxy ratio on the acoustic properties of jute and luffa composites as a function of frequency are determined. Furthermore, the SACs and TLs of some natural fiber-based samples with different thicknesses are predicted using mathematical models and the theoretical and experimental results are compared and evaluated.Article Citation - WoS: 17Citation - Scopus: 19Investigation of the Acoustic and Mechanical Properties of Homogenous and Hybrid Jute and Luffa Bio Composites(Taylor & Francis, 2020) Garip Genç; Hasan Körük; Kenan Y. Sanlıtürk; Yusuf Saygılı; Sanliturk, Kenan Y.; Saygili, Yusuf; Koruk, Hasan; Genc, GaripDesign and development of new biomaterials has become a necessity due to adverse effects of chemical materials on people and nature. As the mechanical properties of biomaterials are not as good as those of chemical materials, their different configurations should be developed and tested before considering them for practical applications. Acoustic and mechanical properties of homogenous and hybrid jute and luffa biocomposites are investigated here. Homogenous and hybrid composites using jute and luffa fibers and epoxy are designed and manufactured and methods for identification of the acoustic and mechanical properties are summarized. Acoustic and structural frequency response functions are measured using homogenous and hybrid composite plates to determine their natural frequencies and loss factors. Using the experimental modal parameters of the plates and their theoretical models, elasticity moduli of biomaterials are determined. The acoustic absorption properties and transmission losses of homogeneous and hybrid composites are determined using impedance tube method. Results show that homogenous and hybrid jute and luffa composites can have moderate absorption coefficients (0.1 for a thickness of 4 mm) and superior damping performance of luffa and stiffness property of jute can be used together to produce hybrid composites with high damping (2.2–2.6%) and elasticity modulus (3–5 GPa).