فهرست مقالات Abdolhamid Gorji


  • مقاله

    1 - An Experimental/Numerical study on the effect of forming parameters in sheet hydrodynamic deep drawing
    International Journal of Advanced Design and Manufacturing Technology , شماره 1 , سال 6 , زمستان 2013
    There are many parameters that affect the sheet hydroforming process such as fluid pressure, material properties, interfacial friction between blank and tool surfaces, etc. In this paper, a FEM-based Taguchi method is used to determine the effects of forming parameters چکیده کامل
    There are many parameters that affect the sheet hydroforming process such as fluid pressure, material properties, interfacial friction between blank and tool surfaces, etc. In this paper, a FEM-based Taguchi method is used to determine the effects of forming parameters on the quality of part formability in the process of hydrodynamic deep drawing assisted by radial pressure. Four important forming parameters, fluid pressure, friction coefficient at blank/punch interface, die entrance radius and the amount of gap between die rim block and blank holder are considered in this investigation. In order to have more comprehensive study, three different workpieces are used as the case studies. Three-dimensional FE models are developed for simulating the forming process. After experimental validation, these models are used for performing the set of experiments designed by Taguchi’s  orthogonal array. The signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) techniques are used to calculate the contributions of each of the mentioned parameters to the output characteristic. The results indicate that fluid pressure in the die cavity and friction coefficient at blank/punch interface are the most influential parameters. Also, die entrance radius and the amount of gap between die rim block and blank holder have considerable effect on the part formability. The obtained results may provide useful guidance on determining forming parameters. Also, further optimization of the forming parameters can be done based on the degree of importance of the parameters on the sheet hydroformability.   پرونده مقاله

  • مقاله

    2 - Investigating the Effect of Electrical Discharge Process Input Parameters on Mechanical Properties of Aluminum Surface
    International Journal of Advanced Design and Manufacturing Technology , شماره 56 , سال 14 , تابستان 2024
    One of the important parameters in electrical discharge machining is the presence of micro cracks on the workpiece surface (recast layer). Therefore, the aim of this study was to investigate the possibility of increasing the mechanical properties of aluminum surface by چکیده کامل
    One of the important parameters in electrical discharge machining is the presence of micro cracks on the workpiece surface (recast layer). Therefore, the aim of this study was to investigate the possibility of increasing the mechanical properties of aluminum surface by alloying elements (copper and nickel) diffusion to the recast layer and thus removing surface micro cracks. For this purpose, pulse on time and pulse current in with and without ultrasonic vibration have been considered as input parameters and the presence of surface micro cracks has been investigated using microscopic images. Also, the yield stress of the surface layer was calculated using the surface micro hardness. Based on the obtain results, surface without micro cracks has been created on the aluminum surface due to the diffusion of copper and nickel into the workpiece surface which increased aluminum surface yield strength from 90MPa to 280MPa without ultrasonic vibrations and to 310MPa while applying ultrasonic vibrations. In other words, ultrasonic vibrations cause an average of 20% increase in surface layer yield strength. In addition, according to the wear test, in the case of using ultrasonic vibration, improving the mechanical properties of the surface has caused thinner grooves on the aluminum surface. پرونده مقاله

  • مقاله

    3 - Improving the surface wear resistance of aluminum by electrical discharge process
    Journal of Advanced Materials and Processing , شماره 2 , سال 6 , بهار 2018
    In this study electrical discharge process was used to increase surface wear resistance of pure aluminum. Pulse-on-time and pulse current were considered as input parameters of the electrical discharge process. Experimental results reveal that the electrical discharge p چکیده کامل
    In this study electrical discharge process was used to increase surface wear resistance of pure aluminum. Pulse-on-time and pulse current were considered as input parameters of the electrical discharge process. Experimental results reveal that the electrical discharge process is a successful method for improving the surface wear resistance of aluminum, so that this method has greatly increased the surface wear resistance of aluminum parts. Results indicate that with increase input parameters (pulse-on-time and pulse current) weight loss of the aluminum specimens is reduced and the wear resistance increases. The XRD analysis demonstrated that Al3Ni2 and AlCu intermetallic compound and Al4C3 were formed on alloyed surface. The presence of these compounds and hard particles at the surface increases the wear resistance. Also, friction coefficient measurements show that, after electrical discharge process and improving surface wear resistance, the friction coefficient slightly increased due to the presence of hard particles on the alloyed surface. پرونده مقاله