Makine Mühendisliği Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1944
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Article Citation - WoS: 1Citation - Scopus: 4Identification of Uncertainty Levels of Acoustic Properties of Biocomposites Under Different Mounting Conditions in Impedance Tube Tests(Institute of Noise Control Engineering, 2021) Garip Genç; Şanlıtürk, Kenan Y.; Yusuf Saygılı; Hasan Körük; Koruk, Hasan; Saygili, Yusuf; Genc, GaripImpedance tube method is widely used to measure acoustic properties of materials. Although this method yields reliable acoustic properties for soft textured materials, uncertainty levels of measured acoustic properties for hard materials, including biocomposites, can be quite large, mainly due to uncertain mounting conditions. Here, the effects of mounting conditions on the acoustic properties of biocomposites in an impedance tube are investigated. First, nominally identical biocomposite samples with a diameter equal to the inner diameter of impedance tube are manufactured and their acoustic properties are determined. As hard materials practically cause fitting problems in the impedance tube, the diameters of samples are reduced, as in practice, by small amounts and acoustic properties of modified samples are determined. Furthermore, in order to match the diameters of samples to the inner diameter of impedance tube, different materials such as tape, petroleum jelly and cotton are applied around samples to close the air gap between the samples and the tube's inner wall. All the results are compared, and the uncertainty levels caused by different mounting conditions on the acoustic properties of biocomposites are identified. The results show that the transmission loss (TL) measurements are dramatically affected by the mounting conditions while the sound absorption conditions are less sensitive to the mounting conditions. The deviations in the measured TL levels are highest for the samples with tape and wax (10–15 dB). On the other hand, the deviations in the measured sound absorption coefficients are highest for the samples with cotton and tape (1–2%).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).Article Citation - WoS: 69Citation - Scopus: 91Investigation of the Acoustic Properties of Bio Luffa Fiber and Composite Materials(Elsevier, 2015) Genç, Garip; Körük, HasanConsidering the adverse effects of petroleum-based materials on nature, finding and developing new materials as alternatives to these chemical materials become a necessity in practice. On the other hand, these new materials need characterization to be considered and effectively used in practical applications. The acoustic properties of luffa bio fiber and composite materials are investigated in this study. First, the preparation of various luffa test samples and the method for acoustic characterization of the luffa samples is presented. Then, the acoustic absorption properties of both luffa fiber and composite materials are identified using the impedance tube method. After that, the transmission loss levels of the same luffa samples are determined. All the results are evaluated and the acoustic performances of luffa materials are highlighted.