Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
Browse
4 results
Search Results
Article Citation - WoS: 23Citation - Scopus: 27Electric Field Effects on Cnts/Vinyl Ester Suspensions and the Resulting Electrical and Thermal Composite Properties(Elsevier Ltd., 2010) Yurdakul, Hilmi; Seyhan, Abdullah Tuğrul; Turan, Servet; Tanoğlu, Metin; Bauhofer, Wolfgang; Schulte, KarlIn this study, electrical conductivity of a vinyl ester based composite containing low content (0.05, 0.1 and 0.3wt.%) of double and multi-walled carbon nanotubes with and without amine functional groups (DWCNTs, MWCNTs, DWCNT-NH2 and MWCNT-NH2) was investigated. The composite with pristine MWCNTs was found to exhibit the highest electrical conductivity. Experiments aimed to induce an aligned conductive network with application of an alternating current (AC) electric field during cure were carried out on the resin suspensions with MWCNTs. Formation of electric anisotropy within the composite was verified. Light microscopy (LM), scanning electron (SEM) and transmission electron microscopy (TEM) were conducted to visualize dispersion state and the extent of alignment of MWCNTs within the polymer cured with and without application of the electric field. To gain a better understanding of electric field induced effects, glass transition temperature (Tg) of the composites was measured via Differential Scanning Calorimetry (DSC). It was determined that at 0.05wt.% loading rate of MWCNTs, the composites, cured with application of the AC electric field, possessed a higher Tg than the composites cured without application of the AC electric field. © 2010 Elsevier Ltd.Article Citation - WoS: 182Citation - Scopus: 214Mode I and Mode Ii Fracture Toughness of E-Glass Non-Crimp Fabric/Carbon Nanotube (cnt) Modified Polymer Based Composites(Elsevier Ltd., 2008) Seyhan, Abdullah Tuğrul; Tanoğlu, Metin; Schulte, KarlIn this study, mode I and mode II interlaminar fracture toughness, and interlaminar shear strength of E-glass non-crimp fabric/carbon nanotube modified polymer matrix composites were investigated. The matrix resin containing 0.1 wt.% of amino functionalized multi walled carbon nanotubes were prepared, utilizing the 3-roll milling technique. Composite laminates were manufactured via vacuum assisted resin transfer molding process. Carbon nanotube modified laminates were found to exhibit 8% and 11% higher mode II interlaminar fracture toughness and interlaminar shear strength values, respectively, as compared to the base laminates. However, no significant improvement was observed for mode I interlaminar fracture toughness values. Furthermore, Optical microscopy and scanning electron microscopy were utilized to monitor the distribution of carbon nanotubes within the composite microstructure and to examine the fracture surfaces of the failed specimens, respectively. © 2008 Elsevier Ltd. All rights reserved.Article Citation - WoS: 143Citation - Scopus: 164Mechanical and Thermal Behavior of Non-Crimp Glass Fiber Reinforced Layered Clay/Epoxy Nanocomposites(Elsevier Ltd., 2007) Bozkurt, Emrah; Kaya, Elçin; Tanoğlu, MetinMechanical and thermal properties of non-crimp glass fiber reinforced clay/epoxy nanocomposites were investigated. Clay/epoxy nanocomposite systems were prepared to use as the matrix material for composite laminates. X-ray diffraction results obtained from natural and modified clays indicated that intergallery spacing of the layered clay increases with surface treatment. Tensile tests indicated that clay loading has minor effect on the tensile properties. Flexural properties of laminates were improved by clay addition due to the improved interface between glass fibers and epoxy. Differential scanning calorimetry (DSC) results showed that the modified clay particles affected the glass transition temperatures (T g) of the nanocomposites. Incorporation of surface treated clay particles increased the dynamic mechanical properties of nanocomposite laminates. It was found that the flame resistance of composites was improved significantly by clay addition into the epoxy matrix.Article Citation - WoS: 18Citation - Scopus: 26Compressive Mechanical Behaviour of E-glass/Polyester Composite Laminates Tailored With a Thermoplastic Preforming Binder(Elsevier Ltd., 2003) Tanoğlu, Metin; Seyhan, Abdullah TuğrulCompressive mechanical behaviour and failure modes of E (electrical)-glass/polyester composite laminates tailored with a thermoplastic preforming polyester binder were investigated under ply-lay up and in-plane loading directions. Fiber preforms with various amount of the binder were consolidated under heat and pressure. The preform compaction experiments were performed by applying compressive pressure to the preforms, and the average thickness as a function of pressure was measured. It was found that the highest compaction of the preforms and therefore the highest fiber volume fraction can be obtained with 3 wt.% of the binder. Further increase of the amount of binder decreases the degree of compaction. Composite panels were fabricated by vacuum-assisted resin transfer molding using fabric preforms with various binder concentrations. The present investigation reveals that there are considerable effects of the binder on the compressive mechanical behaviour of the composites. Compression testing of the composites showed that the average strength values are in the range of 400-600 and 150-300 MPa for ply-lay up and in-plane directions, respectively. Also, both the strength and modulus values increase up to 3 wt.% of the binder, and these values decrease with further addition of the binder. Scanning electron microscopy showed that failure modes of the composites are altered significantly by the presence of the binder. Furthermore, the interaction between the binder and the reacting resin was followed to determine the extent of the binder dissolution and its effects on the viscosity of the resin and the mechanical behaviour of the matrix polymer. The results indicate that there is a partial dissolution of the binder within the matrix resin.