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In recent years, aluminum, magnesium and titanium alloys are highly regarded in the aerospace and automotive industries due to their high strength to weight ratio and resistance to corrosion. The main problem of the use of these alloys is their low formability at room temperature. To solve this problem, the metal forming process is done at high temperatures. Since oil’s heat resistant temperature is not more than 300°c, other fluids such as air and nitrogen gas should be used in high temperatures. In this study, blow forming equipment at high temperatures has developed, and changing of AL6063 tubes cross-section from circular to square has investigated experimentally and compared with the results of the experiments at room temperature. After producing square products, thickness distribution, corner’s radius, forming pressure, and effect of pressure time in corner’s radius at different temperatures were compared and the location of bursting was also examined. The results indicated that by increasing temperature, formed radius and pressure time reduces significantly, so that the amount of radius decreases from 19.5 mm in the temperature of 25°c and 154 bar forming pressure, to 5.8 mm in the temperature of 500°c at 11 bar forming pressure. The results showed that by increasing time pressure, which causes to decrease velocity of process, the formed corners has been sharper. By investigating burst of specimens, bursting occurs in the area of converting circular cross section to square one, which has a high deformation and tensile strain.

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Due to the polar functional groups of PVC thermoplastic and its good adhesiveness to the metals, production and roll forming of PVC/ aluminuim/ glass fiber FMLs were investigated in this research. At the first, flexural strength and bonding quality between PVC matrix and aluminuim layer in the FMLs were studied by doing three point bending tests according to ASTM D790 standard. In the following, FMLs with dimension of 12×80 cm and two layups including [0/90, 0/90, Al]s and [45/-45, 45/-45, Al]s were produced using film stacking and hot pressing procedure. The FMLs were rollformed into 30, 45 and 60º channel section profiles at 160ᵒC using a single stand rollforming process and geometrical decects including profile bowing, edge wrinkling, spring back and also aluminuim/composite layers delamination of the resulted profiles were evaluated. The FMLs also were roll formed into 86º channel section profiles using a multi stand roll forming process and the effects of multi stand roll forming on the defects stacking were evaluated. Finally, it was concluded that more than 45º bend angle increase in a rollforming stand results in composite/ aluminum delamination. Also, placement of the reinforcing fibers in the longitudinal direction of the profiles reduces the profile bowing and edge wrinkling defects significantly.

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Manufacturing in as short time as possible, with highest quality and at minimal cost, is one of the key factors in industry. As a result, researchers are seeking new methods and technologies to meet such requirements. Liquid impact forming is one of such methods which has received wide currency especially in automotive and aerospace industries. In this method, which is considered as one of tubular hydroforming processes, forming is achieved by using liquid pressure. In this paper, liquid impact forming process was investigated experimentally and numerically for a thin-walled aluminium tube. In experimental part, a die was designed and manufactured to transform the cross section of the aluminium tube into a polygon which at the end of the process changes the cylindrical shape of the tube to a profile almost similar to a trapezoid. Results showed that a die in the form of matrix molding is not suitable for this type of geometry in such a process while using another die which consisted of three parts resulted in a satisfactory forming. Simulation of this process was further implemented using finite element method and results relating to Von Mises stress distribution, displacement, strain energy, internal energy, thickness variation and the force required to implement the process were obtained. Displacement distribution in different regions indicated that no wrinkling occurred in the sample. Comparison between simulation and experimental results indicated that they were in good agreement.

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Hot metal gas forming is a process to form metals with low formability or high strength at room temperature such as aluminum, magnesium and titanium. With increasing temperature, the formability of these metals increases and the strength decreases. In this process, for producing parts with desirable properties, determination of optimal parameters is essential. In this study, hot metal gas forming process was simulated by using Abaqus software, and the influences of input parameters on the outputs were evaluated with simulation results. In order to validation of simulation results, the experimental test was carried out by using hot metal gas forming setup. For modeling hot metal gas forming process, an artificial neural network in Matlab software were trained by using data obtained from the numerical simulation. In this neural network, pressure, axial feeding and time were assumed as input parameters and the radius, minimum and maximum thickness were considered as output. In the next stage, this model was implemented as input function in multi-objective genetic optimization algorithm to obtain Pareto front and the optimum process parameters. Obtained optimum parameters include: pressure 13.07bar, axial feeding 0.78mm and time 65.73s and the values of corner radius, minimum and maximum thickness obtained from the optimum parameters are 5.49mm, 0.92mm and 1.57mm respectively.

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Tube multi-point hydroforming is a new flexible forming technology for manufacturing of various tubular parts that presented and investigated in this paper for first time in the world. In this process, one die is enough to deform tubes to different shapes by utilizing high pressure fluid. In conventional hydroforming, it is necessary to manufacture different dies for producing different geometrical parts. This requires higher process time and cost. In present novel, tube multi-point hydroforming is investigated via FE simulation and experiments. In this process a new die based on multi point forming were designed and manufactured. Due to good formability of brass 70/30, a bulged tube and a rectangular tabular cross section of brass with initial thickness of 2mm are produced by applying this die to the process. The main difference between multi-point die and conventional dies is substituting the rigid surface by wide spaced pins. By adjusting the pins height, different tubular cross sections could be produced. This process is simulated and verified experimentally and defects are predicted. In order to decrease these defects an elastic layer of polyurethane is used. According to the simulation, maximum decreases in thickness are 11% and 17% for the bulged and rectangular cross section samples. These results are matched with the experiment.

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Additive manufacturing methods and/or 3D printing have become increasingly popular with a particular emphasis on methods used for metallic materials. Selective Laser Melting (SLM) process is one of the additive manufacturing methods for production of metallic parts. The method was developed in particular to process metal parts that need to be more than 99 percent dense. In this method, according to a predefined pattern, the top surface of the powder layer is scanned by the laser and a local (selective) melt pool is produced in the place of the laser spot which results in a fully dense layer after solidification. In this study, a semi-coupled thermo-mechanical simulation of SLM process is carried out in ABAQUS finite element software. In order to simulate the moving heat flux and update material properties from the powder to the dense solid, the ability of the software for employing user-defined subroutines is employed. Investigation of the residual stress distribution and distortion of a part built using SLM process are the main objectives of this simulation. Results which are presented for two different mechanical boundary conditions show that when the bottom face of the layer is clamped, the top face of the built layer deforms in a concave shape, while the lateral faces of the layer have simply-supported boundary conditions and the bottom face of the layer is free, the part is warped.