Yazar "Lazoğlu, İsmail" seçeneğine göre listele

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    Effect of polyurea coating on the ductility of aluminum foam
    (Elsevier Ltd, 2022) Bijanzad, Armin; Abdulwahab, Mohamad; Lazoğlu, İsmail; Ensarioğlu, Cihat; Çakır, Mustafa Cemal
    The closed-cell metal foams are utilized in various industrial applications due to their impact and energy absorption capacity, noise cancelation, and lightweight properties. Additionally, the manufacturing methods of stochastic foams with blowing agents or inert gas injection are well known. However, the poor mechanical strength and high brittleness are restricting the application of these materials. A method of increasing the ductility, plastic deformation, and fracture toughness of these materials is the integration of elastomer coating. Polyurea is widely used in applications where water-proofing and high ductility are aimed. In this study, two types of polyurea coatings as MS950 and MS955 are sprayed over the aluminum foam with three densities as 0.508, 0.557, and 0.624 g/cm3 to evaluate the effect of coating on the ductility and fracture toughness of samples considering the tensile behavior and 4 densities as 0.508, 0.538, 0.557, and 0.624 g/cm3 for the flexural bending test. The MS955 polyurea coating elevated the ultimate tensile strength and elasticity modulus of all specimens with a maximum of 239% and a minimum of 70%. However, the MS950 coating did not result in a significant rise in tensile strength. The main advantage of the MS950 coating is in the amount of strain increment with 374% in maximum and 181% in minimum resulting in higher ductility and fracture toughness. Additionally, the bending characteristics of MS950 coating demonstrate a drastic increase in both load and strain which recommend the usage of this coating in bending and impact applications. Finally, an analytical evaluation of the coated and uncoated specimens in the elastic region and the elastoplastic region is provided using linear and power-law interpolation. In tensile tests, the MS955 coating resulted in higher elasticity modulus and fracture toughness. However, in bending applications, the MS950 coating demonstrated higher load strength with elevated ductility. © 2022 Elsevier Ltd
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    Effects of polyurea coating on the elastoplastic behavior of additively manufactured PLA specimens
    (SPRINGER, 2022) Abdulwahab, Mohamad; Bijanzad, Armin; Khan, Shaheryar A.; Lazoğlu, İsmail
    The fused Filament fabrication method gained its popularity in the additive manufacturing industry not only because of the low capital and manufacturing cost, but also due to its ease of production approach, availability, and mobility of the method. However, the quality of fnal parts and the mechanical properties are directly related to layer thickness, resolution, flament raw material, and working temperature. Thermoplastic materials, especially polylactic acid (PLA), are widely used considering their low melting temperature, lower requirement of post-processing, and sustainability. However, poor mechanical properties, layer delamination, and low ductility are the main drawbacks of these materials. This work aims to study the efects of polyurea as an elastomeric coating on PLA printed specimens. Three geometrical confgurations were prepared, and tensile properties of coated and uncoated samples are investigated using stress–strain curves. It has been shown that hot polyurea coating results in a reduction in the ultimate tensile strength (UTS) of specimens. However, it increases ductility and elongation performance of the samples remarkably. In addition, the elasticity modulus and elastoplastic behavior of the specimens are modeled mathematically.
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    In silico evaluation of lattice designs for additively manufactured total hip implants
    (2022) Izri, Zineddine; Bijanzad, Armin; Torabnia, Shams; Lazoğlu, İsmail
    Additive manufacturing restructures the fabrication of custom medical implants and transforms the design, topology optimization, and material selection perspectives in biomechanical applications. Additionally, it facilitated the design and fabrication of patient-oriented hip implants. Selection of proper lattice type is critical in additive manufacturing of hip implants. The lattice types reduce the implant mass and, due to higher stress distribution and deformations as compared to the rigid implants, it brings down the stress shielding issues. This study introduces a rigid shell structure and infill lattice hip implant. Additionally, the effect of various lattice unit cell thickness (0.2-1 mm) and elemental size (2.5-5 mm) while applying 2300 N axial force is explored numerically. A cubic structure with two rigid surfaces on the top and bottom is outlined to separate the effect of the hip implant cross-sectional area variations. The stress distribution and deformation characteristics are validated with the hip implant design. The Finite Element Analysis (FEA) demonstrated that the Weaire-Phelan lattice structure exhibits the least stress and deformation among the other types at various design parameters. Additionally, the same methodology is applied to three biocompatible hip implant materials as Ti-6Al-4V, TA15 (Ti-6Al-2Zr-1Mo-1V), and CoCr28Mo6. Finally, the effect of the unit cell thickness and size on the implant's mass reduction considering the lattice's safety factor is investigated for the mentioned materials. The selection of a Weaire-Phelan lattice with the optimized safety factor and mass reduction is represented considering all the results. The optimized parameters for Titanium-based alloys are approximately 3.5 mm unit cell size with 0.6 mm beam thickness. However, the CoCr Mo-based alloy requires a thicker beam size (about 0.8 mm) due to lower safety factors.