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Additive manufacturing (AM) technology is widely used to fabricate complex 3D products directly from CAD file. Laser-based Powder Bed Fusion process (L-PBF) is considered the most important AM techniques that can produce high-quality Tool Steel products such as dies for Aluminum High-Pressure Die Casting. Traditional techniques face significant challenges due to mold design complexity and water cooling system channels, which are needed to reduce the die temperature and to allow fast cooling of the casting. These challenges can be solved by applying AM techniques. In L-PBF, several process parameters such as Laser scanning speed, layer thickness and laser power affect the quality of the product. In the present work, L-PBF technique was used to prepare H13 tool steel samples using different Laser scanning speeds, ranging from 150 mm/s up to 600mm/s, as it is the main process parameter affecting both the quality and the productivity of the produced parts. The microstructure after L-PBF process was analyzed using optical, and SEM microscopy as well as x-ray diffraction. The mechanical properties were determined by using tensile, impact toughness and hardness tests. The results refer to the powerful effect of the scanning speed of laser, on mechanical properties, porosity formation, and the observed microstructure of H13 tool steel.

Egypt plays an important role in the consuming markets for tires all over the world. There is an urgent need to get rid of them in an economic and environmental way since it is considered as a harmful waste if burnt. The World trend is directed towards the improvement of new techniques to insert the rubber into useful products to maximize the benefit of recycling. This research deals with the expansion of novel techniques for rubber powder recycling for various purposes in a robust construction. Recycled rubber particles (RRP) are mixed with ordinary Portland cement (OPC) using various water to binder ratio (W/B) at 0.3 and 0.4. The Fourier transform – infrared (FT-IR) spectra is measured for RRP. The compressive strength (C.S) is investigated for the rubberized cement pastes at 1, 3, 7, 14 and 28 days. The results aimed to enhance the compressive strength of rubberized cement pastes through improving the bonding strength between RRP and OPC by using fine particles of RRP. Maintaining the compressive strength in the highest levels with different RRP percentages in addition to the vibrational damping property of RRP gives rubberized cement pastes the advantage to replace ordinary concrete in most construction applications.

The possibility of using marble and granite dust in the industry was investigated. The reuse of waste is expected to reduce cost, ensure sustainability and green solution. This study was focused on the source of this waste, amount and effect on the environment. It is intended to use this marble and granite dust as dispersed particles in high density polyethylene to obtain a novel composite material. The effect of marble and granite dust weight percentage (10–70 wt%) and the particle size (75–2300 μm) on the mechanical properties of the composite were studied. In this work, thermal degradation and chemical composition of the marble and granite dust were also determined. The experimental results showed that by increasing the dust percentage, flexural strength and elastic modulus increased. The fracture surface of the tested specimens under impact was studied using scanning electron microscopy.

In this work, a novel laminated polyester composite that contains waste tire rubber particles and glass fiber is developed. This composite is expected to possess better mechanical and physical properties, than other conventional polyester composites which consist of CaCO3 and glass fiber. This novel composite can be used in car bodies and in the aviation industry. Flat laminated specimens from both composites are prepared by hand layup. Tensile and impact testing are done to evaluate and compare the mechanical properties of these composites. An experiment is done to study the damage that can occur to the novel composite when drilling holes which can be used for joining composite laminates with other parts. Twelve trials were made to reduce the damage by better selection of the drilling conditions. Peel up and push out delamination factors are calculated to investigate the damage. Digital optical microscope is used to investigate the fracture surface of broken specimens and the nature of drilling damage. Comparison between novel and conventional composites shows an improvement by approximately 47% and the density of the new composite decreases by 8%. The optimum drilling cutting speed is approximately 1150 rpm which gives the least delamination factor at the front and back of specimen.

The purpose of this work is to investigate the opportunity of re-using M&G wastes to get novel PP composites. Recycling of marble and granite (M&G) wastes has the advantage of cost reduction and eco-friendly production. M&G productions generate a large amount of wastes. The handling of such wastes by incorporating them into a polymer is a practical solution for waste management. These composites can be utilized in several applications to produce low-cost products. The effect of the mass percentage of marble and granite dust on several mechanical and physical properties was examined. The mechanical (pin load behavior) and physical (thermal, water absorption and density) properties of PP composites were investigated using 0–50 mass% M&G dust particles. Adding M&G wastes increases the onset temperature.

Organic solar cells (OSCs), also known as organic photovoltaics (OPVs), are an emerging solar cell technology composed of carbon-based, organic molecules, which convert energy from the sun into electricity. Key for their performance is the microstructure of the light-absorbing organic bulk heterojunction. To study this, organic solar films composed of both fullerene C60 as electron acceptor and different mole percentages of di-[4-(N,N-di-p-tolyl-amino)-phenyl]-cyclohexane (TAPC) as electron donor were evaporated in vacuum in different mixing ratios (5, 50 and 95 mol%) on an ITO-coated glass substrate held at room temperature and at 110 °C. The microstructure of the C60: TAPC heterojunction was studied by grazing incidence wide angle X-ray scattering to understand the effect of substrate heating. By increasing the substrate temperature from ambient to 110 °C, it was found that no significant change was observed in the crystal size for the C60: TAPC concentrations investigated in this study. In addition to the variation done in the substrate temperature, the variation of the mole percent of the donor (TAPC) was studied to conclude the effect of both the substrate temperature and the donor concentration on the microstructure of the OSC films. Bragg peaks were attributed to C60 in the pure C60 sample and in the blend with low donor mole percentage (5%), but the C60 peaks became nondiscernible when the donor mole percentage was increased to 50% and above, showing that TAPC interrupted the formation of C60 crystals.

The effect of alumina nanoparticles and the dispersion homogeneity on the composite performance, in terms of mechanical and physical properties, has been studied extensively. The effect of alumina nanoparticles weight percentage (0.25–0.5–0.75–1 wt%) and particle size of 60 nm mixed with commercial epoxy resin (Kemapoxy 150) are used in this investigation. Bending, hardness, tension, erosion, water absorption, and TGA tests are studied. Experimental results indicate improvement in the mechanical behavior with 0.25 wt% particles for both bending strength and wear resistance by 7 and 67% relative to pure epoxy. Water absorption depends mainly on particle distribution, and TGA testing slightly increases with the increase in particles dosage. The tested samples were studied using environmental scanning electron microscopy. Good distribution and dispersion of nanoparticles in the epoxy matrix lead to reducing the mobility of the epoxy chains due to the formation of high immobile nano-layers around the alumina nanoparticles. Thus, creating hydrogen bonding between chains and particles. Consequently, increased constraints between particles/polymer chains and polymer chains themselves are found leading chains to bear extra forces. Fracture strength decreases due to nanoparticles agglomerations causing an increase in the space distance (free volume space) between epoxy chains. This study suggests possible applications of the tested coating due to improved mechanical and physical properties upon nanoparticles addition.

The joining of rubber polyester composite is affected by design and geometry parameters. These parameters affect the failure load of the composite joint and the failure mode. Catastrophic failure modes should be avoided, and the optimum parameters are selected to achieve a progressive failure that could be observed. Geometry parameters such as the edge distance and the center distance between holes are tested under tensile loading to get the optimum values. Design parameters such as tightening torque of bolt and washer size are also tested under tensile loading, and their effect on the failure load is obtained and studied. The failure modes are investigated under the digital microscope in each case. It is found that the failure load increases by increasing the edge distance, the tightening torque, and decreasing the center distance between holes. The optimum washer size is varied according to the used tightening torque. The optimum obtained failure mode in tests is a mixed - mode of bearing and net tension modes.

Natural fibre-reinforced polymer composites are standing in the limelight of investigations due to their light weight and availability from natural and renewable resources. Improved mechanical and physical behaviour is targeted through hybridisation with other reinforcing elements. This study investigates the potential of adding silicon carbide particles at volume contents ranging between 2 and 8% to jute fabric-reinforced epoxy composite to produce such hybrid composites. In contrast to the commonly applied processing technique of hand layup used to produce natural fibre-reinforced laminates, the vacuum-assisted resin infusion method was applied in this study to produce high quality laminates. Samples were tested for their mechanical behaviour through tensile, flexural and impact tests. Scanning electron microscopy was further performed to analyse the modes of failure of the composites. Finally, erosion tests were conducted, by directly sanding the hybrid composite samples to evaluate their erosion wear resistance. Results indicated that the addition of particles had a significant effect on the tensile, flexural, impact and erosion wear behaviour of the composites under investigation. Hybrid composites reinforced with 4 vol.% SiC exhibited acceptable mechanical properties. The behaviour was found to deteriorate at SiC contents beyond 4 vol.%.

In this work, a novel composite of polyester with rubber particles-obtained from recycled wasted car tires - was developed. Worn tires generate a large amount of wastes that do not derogate resulting in environmental problems. This has the advantage of producing useful product that is economical and eco-friendly. The effect of the volume fraction of the rubber particles in the composites on the physical and mechanical properties of the composites was studied. Varying the volume fraction from 0-60% resulted in an increase in the impact properties. The addition of rubber particles had also the effect of reducing the density of the composites which is a desirable property.

The main objective of this study is to review the capability of using marble dust particles as reinforcing materials in polymeric composites. In this study, it is intended to obtain a novel composite material by using these particles as reinforcement in polypropylene (PP) matrix. The effect of different particle sizes (35–1350 μm) and the weight percentage of marble dust particles (10–70 wt%) on the thermal and mechanical properties were investigated. In addition, thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and Energy-dispersive X-ray spectroscopy (EDX) of the dust particles were studied. It was found that the thermal and the mechanical properties (such as flexural strength, compressive strength, elastic modulus and hardness) of the composites were improved by adding the dust particles into the PP matrix. The experimental results were observed and the optimum conditions were determined. The fracture surface of the tested samples under bending was studied using scanning electron microscope (SEM). SEM images show the dust particles agglomeration and the pullout of this particles which are responsible for the strength reduction in the composites.

In this study three factors affecting stress distribution in horizontal axis wind turbine blade are studied using ANSYS Fluid-Structure Interaction (FSI) simulation. The first factor is the cross-section of the wind turbine blade which is selected to be an airfoil. The second factor is the twist angle of the blade while the third factor is the material. A study of two different airfoils is made for three different blades’ twist angles and two different materials to obtain the results of total deformation, stress distribution and maximum equivalent stress (von-Mises) along the blade length. This study emphasizes the importance of a multi-disciplinary research where computer, mechanics, and materials engineering are involved. The fields Computational Mechanics, Mechanical Design and Materials Engineering are used in the analysis of wind turbine blade in this study. Also understanding in depth the stress distribution in wind turbine blades could improve the design of wind turbines and lessen the cost of the clean wind energy.

the main objective of this study is to examine the capability of using marble dust in industry. The re-use of cement-based materials waste is expected to reduce the cost and insure sustainability. This study focused on the source of this waste and its effect on the environment. Also, it is intended to obtain a novel composite material by using these dispersed particles as a reinforcement in low density polyethylene (LDPE) matrix. The effect of different weight percentage of marble dust particles (10–50%) on the mechanical and physical properties were also investigated. On of the other hands, scanning electron microscopy with an energy dispersive X-ray spectrometry (SEM–EDX) was used to study the morphology and the elemental composition of the marble dust particles. The experimental results were observed, and the optimum conditions were determined. It was found that the mechanical and thermal properties (such as flexural strength, compressive strength and hardness) of the LDPE composites were improved by adding the marble dust particles into the LDPE matrix.

The properties of these polymers, as in the case of any materials, depending on the molecular weight of the polymer and the structure of the polymer chains. The main objective of this work is to study the mechanical and physical properties of pure PP and HDPE. To obtain a full characterization of pure polymer, samples were produced using a compression molding technique. Polymeric samples successfully filled the cavity of the die. The mechanical properties of PP and HDPE were determined using three-point bending, compression, hardness and impact test. While the physical properties were studied through density and water absorption. Also, the thermal analysis behavior was determined by thermogravimetric analysis, differential scanning calorimetry and thermomechnical analysis. Results showed the structure affects the properties. The PP showed better elastic modulus and strength due to the methyl attached to the carbon that prevents the chain rotation and hence makes the material stronger but inflexible. On the other hand, the absorbed energy of PP is less than that of HDPE. The thermogravimetric analysis results show a single weight-loss event with a degradation temperature of 310°C for HDPE and 255°C for PP. The differential scanning calorimetry shows that the crystallinity of PP (≅51) is less than that for HDPE (≅68) due to the difference in the specific heat. The coefficient of thermal expansion of HDPE is higher than that of PP due to the stronger interatomic forces.