Advanced Materials Research Vol. 1119

Abstract: The main goal in this investigation is optimization of two, four, eight and twelve layer shells in order to identify optimized fiber angle in different layers aiming maximizing critical load. In order to identify critical load parameter, a hybrid approach including Finite Element Method (FEM) and Neural Networks (NN) is employed. To achieve the above results, required data for NN is supplied by FEM and the appropriate network is trained. For optimization of obtained function, Genetic Algorithm (GA) is utilized. In this case, GA is also employed over and over in order to obtain the effect of different parameters. Furthermore, existence of several close optimized points and interactions among layers, critical load and fiber angle are discussed.

Abstract: Anodizing process conducted in Al7xxx/SiC produced non-uniform thickness of porous anodic film with cavities, micro-pores and micro-cracks. Cerium sealing was chosen as a post treatment to remedy the poor anodic film by providing a composite layer in order to further enhance the corrosion resistance in aggressive environment. In this study, anodizing process was conducted in H₂SO₄ solution at current density values of 15, 20, and 25 mA/cm² at room temperature, 0°C and-25°C for 30 minutes. Subsequently, electroless sealing was conducted in CeCl₃.6H₂O + H₂O₂ solution at room temperature and pH 9 for 30 minutes. Integrated protection composed of anodizing at 0°C and cerium sealing process in Al7xxx/SiC produced cerium rich deposits in the diameter of 64 nm (± 3nm) on the surface of anodic oxide layer. These spherical deposits covered the entire surface of anodic oxide layer in accordance with the morphology of the oxide layer. Otherwise, almost no cerium deposit formed on the surface of the oxide layer by conducted integrated protection at room temperature and-25°C. The integrated process conducted at anodizing temperature of 0°C presented a highest protection degree. The cerium protective layer which leads to the decreasing of corrosion rate and current density up to 99,99% or four orders magnifications than that of bare composite.

Abstract: In the present study, Buckminster Fullerene and glass fiber reinforced Polyamide 66 multiscale composites were produced using laboratory type twin screw extruder and injection molding machines, respectively. The glass fiber reinforcement was set as 30 wt % and samples A, B and C were produced with 0.1, 0.5 and 2.0 wt % Buckminster Fullerene addition besides the glass fiber reinforcement. Tensile tests were conducted and their results were compared with samples having only 30 wt % glass fiber reinforcement to investigate the effect of Buckminster Fullerene addition. The morphological structure of the multiscale composites were investigated using scanning electron microscopy (SEM) analysis.

Abstract: Mechanism of fracture of polypropylene composite reinforced by kenaf fiber under cyclic loading was investigated. Weight fraction of the composite used is 50% polypropylene and 50% kenaf fiber with random fiber orientation. Skins of composite that contains polypropylene dominant fraction are formed on both surfaces. The experiments were performed with flat specimen under cyclic flexural loading with constant displacement. Cyclic softening was detected by hysteresis loop of a local area. Deformation of the specimen was measured from the observed cycles. Fracture features were investigated using optical microscope and scanning electron microscope. The result shows that polypropylene-kenaf composite with 50%-50% fraction with random fiber orientation has complicated fracture features. The damage of the composite started from internal part. The surface crack proceeded after the internal damage. Moreover, it is discussed that some of fibers were covered by only thin matrix. The strength of specimen was determined the fracture behavior of fibers.

Abstract: Water molecule reacts with aluminium when it is immersed in water, which plays a vital role in hydrogen generation process. This process which uses sodium hydroxide as catalyst produces a byproduct alumina and some other scarce ingredients. This byproduct is mentioned as alumina composite powder (ACP). In an attempt of reutilizing and converting it into a matrix material using a resin polymer as a binder, this work investigates the workability of the product produced by alumina composite matrix. The specimen produced by alumina composite matrix has been tested for its desirable strength, namely, tensile strength, elongation under varied thermal conditions, compression test, flexural test with fiber reinforcement and non fiber reinforcement. The nature of crack formation and the plastic behavior of the specimen during test have been analyzed, based on the crack propagation in failure plane in the alumina composite matrix as a high quality alternative for wood and tiles for high class interior decorations. This research explores the effective use of the byproduct alumina composite matrix and its consistent eco-friendly nature.

Abstract: The excellent mechanical properties of Aluminium Metal Matrix Composites find applications in a variety of engineering applications in the automotive, aerospace and heavy machinery industries. This study aims at synthesis and characterization of Al 64430 reinforced with SiC particles and Rice Husk Ash (RHA). Rice husk ash is an agricultural waste which is produced in millions of tons worldwide. Aluminium was used as the base metal. With liquid metallurgy technique the metal matrix composites were prepared. The MMCs were synthesized with 3 % weight percentage RHA in Al metal matrix and the mechanical properties such as hardness, tensile strength and structural properties of MMCs were studied. The microstructure of the synthesized composites was examined by optical emission microscope and XRD. The Vicker’s microhardness test was performed on the composite specimens from base of the cast. The synthesized MMCs were found to have increased tensile strength, hardness, increased ultimate strength. The density of MMCs was observed to be decreased. This study indicates that RHA can be used as reinforcement material to synthesize light weight composites with increased hardness, tensile strength, Young’s modulus for various industrial applications.

Abstract: Scaffolds material is the key factor for bone tissue engineering, and construction of the scaffolds is also an important part. Adopting the biocompatible, biodegradable, hydroxyapatite (HAP) and sodium alginate (SA) as the molding material, using three-dimensional printing technology, choosing cross grid filling paths, we manufactured the artificial bones through self-developed 3D printing equipment. Then we measured and analyzed important parameters of the work, and did composite culture experiment. It can be seen that the prepared artificial bone scaffold has good biocompatibility. The paper provides a reference for the study of bone tissue engineering materials.

Abstract: Polycarboxylic type water reducers were synthesized at different molar ratios of acrylic acid to methyl-allyl polyethylene glycol2400 (acid/ether-ratio). Influence of the acid/ether ratio on its composition and dispersive property were studied by means of Gel Permeation in Chromatography (GPC) and fluidity test of cement paste. The GPC analysis results showed that the average molecular weight and polydispersity were increased with the increase of acid/ether-ratio, but the polymerization degree should be no longer increased as which reached to a certain value, the excessive small-monomers would be self-polymerized when macro-monomers had been consumed. As the final product of polymer at an acid/ether ratio of 5:1, was composed of un-reacting macro monomer (about 6%) and the copolymer of water reducers (about 92%) and the copolymer of small monomers (about 2%). The result of fluidity of cement paste showed that the acid/ether-ratio also influenced the dispersive property to different cement, its ability would be bad if at the ratio of 2:1, then the property of dispersive and fluidity retaining should be all well if at 3.5:1, and the beginning dispersive ability might be high but the ability of fluidity retaining be low as the ratio was beyond 4.5:1.

Abstract: IPMC (Ionic Polymer Metal Composite) is promising candidate actuator for bio-related applications mainly due to its biocompatibility, soft properties and operation in wet condition. In this paper, a new actuator will be presented. The tubular actuator, based on the concept of tip-displacement of IPMC actuator and capable of generating bending of tube with surface outside electrodes, was proposed and studied experimentally. The actuator is a Nafion tube consisting of an even number of Pt segments along the length, which are plated outside of tube surface, and the Pt segments act as electrodes to apply the driving voltage. The experimental data measured on prototype actuators prove the proposed concept of bending depend on the shape of Nafion. Show that the actuator functions well both displacement and force.

Abstract: In this paper, the sundi wood dust reinforced epoxy composite is developed with three different filler content. The tensile and flexural tests are performed at three different speeds to study the mechanical behavior of the composites. Experiments are conducted based on central composite design considering two factors viz. speed and filler content. The experimental data are statistically analyzed by using analysis of variance to find out the significant parameters. Response surface design has been employed to determine optimum design parameters. It has been observed from the analysis that speed is the main significant factor affecting the load and tensile stress values but for flexural stress, filler content is the main significant factor at 95% confidence level.