In this investigation, mechanical properties of composite materials produced from woven jute type were investigated. These composites were produced in the form of epoxy adhesive layers by using hand lay-up method in which aluminum, mica and ceramic particles were added into epoxy as a structural adhesive by 2, 4 and 6 wt%. Samples produced according to ASTM D procedures were subjected to tensile and three point bending loads to examine the effect of the particles. Experimental results were presented in tables and graphs. As a result, it was observed that the tensile and bending failure loads of the composite materials obtained by using the particle reinforced adhesive increased. Also, the biggest rise in tensile strength was achieved with 4 wt% aluminum and the biggest increase in bending strength was observed for 2 wt% aluminum particles.

In recent years, consumers have become increasingly interested in natural, biodegradable and eco-friendly composites. Eco-friendly composites manufactured using natural reinforcing filling materials stand out with properties such as cost effectiveness and easy accessibility. For these reasons, in this research, a composite workpiece was specially manufactured using eco-friendly jute fibers. Two cost-effective cutting tools were specially produced to ensure high-quality machining of this composite workpiece. One of these specially manufactured cutting tools was subjected to DC&T (deep cryogenic treatment and tempering) processes to improve its performance. At the end of the research, when the lowest and highest Fd (delamination factor) values obtained with DC&T-T1 and T1 cutting tools were compared, it was observed that 5.49% and 6.23% better results were obtained with the DC&T-T1 cutting tool, respectively. From the analysis of the S/N (signal-to-noise) ratios obtained using Fd values, it was found that the most appropriate machining parameters for the composite workpiece used in this investigation were the DC&T-T1 cutting tool, a 2000 rev/min spindle speed and a 100 mm/min feed rate. Through ANOVAs (analyses of variance), it was discovered that the most significant parameter having an impact on the Fd values was the spindle speed, with a rate of 53.01%. Considering the lowest and highest Ra (average surface roughness) values obtained using DC&T-T1 and T1 cutting tools, it was seen that 19.42% and 16.91% better results were obtained using the DC&T-T1 cutting tool, respectively. In the S/N ratio analysis results obtained using Ra values, it was revealed that the most appropriate machining parameters for the composite workpiece used in this investigation were the DC&T-T1 cutting tool, a 2000 rev/min spindle speed and a 100 mm/min feed rate. In the ANOVAs, it was revealed that the most significant parameter having an effect on the Ra values was the feed rate at 37.86%.

In this research, silver nanopowder (at rates of 0%, 0.5%, 1%, 1.5% and 2%) was added to 925-carat silver-copper alloy used in manufacturing silver jewellery to increase its durability and to observe its mechanical properties occurred. In this context, different mechanical tests (tensile, bending and hardness) were performed on exclusively produced silver-copper alloys. Moreover, mechanical simulation tests were conducted via ANSYS software using the data obtained from the experimental results. In the tensile tests, it was observed that the use of nanopowder at the rates of 0.5% and 1% positively affected the tensile strength and strain values, while when the nanopowder rate exceeded 1%, both parameters were negatively affected. According to tensile test results, the ductility of the alloy material decreases as the rates of nanopowder addition rise. In the bending tests, it was observed that the addition of 1% nanopowder increased the bending strength significantly; however, other addition rates had a negative effect. Hardness measurements showed that the 1% nanopowder ratio had a much higher effect (in terms of increasing the hardness value) on the hardness value than 0.5%, 1.5% and 2% nanopowder ratios. In order to verify the numerical analysis model, the results of both experimental and numerical analyses were compared. The success of numerical modelling was found to be ∼96% in terms of both tensile strength and displacement. Many methods are used in the jewellery industry, especially in silver jewellery. To easily shape the material to be used in filigree, repousse, and tattoo techniques, the material must be somewhat soft and pliable. Therefore, if production is carried out using these techniques, it is not advisable to add large amounts of nanopowder to the alloy. Furthermore, adding quite low amounts (0.1%, 0.5% etc.) of nanopowder to the silver-copper alloy will provide efficient results in shaping-based production techniques.

Vehicle crush boxes are one of the safety elements used in vehicles to minimize damage that may occur during an accident. The task of crush boxes is to absorb the energy which is generated during an accident. In this study, peak force, energy absorption and specific energy absorption values of cylindrical composite crush boxes, to which 0.25% and 0.50% graphene was added, were experimentally investigated with hydrothermal aging. The composite crush boxes were produced with vacuum infusion method. Glass, aramid and carbon fibers and their hybridizations were used as fibers. During hybridization, the winding order of the fibers was changed from inside to outside. The parameters for hydrothermal aging were selected as 500 h and 1000 h at 60 °C. The highest energy absorption value was obtained in the carbon fiber-reinforced sample CFRPG1H2 with 0.25% graphene-added epoxy resin matrix, aged for 1000 h. The lowest peak strength was observed in the aramid fiber-reinforced sample AFRPG2H2 with 0.50% graphene-added epoxy resin matrix, hydrothermally aged for 1000 h. It was observed that increasing the graphene addition rate reduced the negative effects on aging. It was determined that increasing the graphene ratio by 0.25% had an effect on aging.