List of Articles erfan mirshekari

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  1 - Performance analysis and optimization of 6-DOF Hunt type parallel robot
  erfan mirshekari َAfshin Ghanbarzadeh
  In this research, Hunt type 6-DOF parallel robot is optimized based on kinetostatic performance indices and the effect of geometrical parameters on these indices is investigated. For this purpose, structural and geometrical parameters of Hunt type parallel robot are int More

  In this research, Hunt type 6-DOF parallel robot is optimized based on kinetostatic performance indices and the effect of geometrical parameters on these indices is investigated. For this purpose, structural and geometrical parameters of Hunt type parallel robot are introduced. in order to determine the relationship between joint angle values and end effector coordinates, inverse kinematic is obtained. Jacobian matrix is developed to map velocity from joint space to Cartesian space. Manipulability, force manipulability and condition number are considered as indices to evaluate the robot performance. By defining the fitness functions, constraints and boundaries of geometric parameters, the optimized parallel robot structure is obtained using the multi-objective bees algorithm. A set of robot geometric parameters is presented, each of which has the best performance based on one of the indices. Also, a robot with specific geometric parameters is selected, which is suitable based on almost all performance indices. Finally, the effect of end effector movement on robot performance is investigated. Manuscript profile
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  2 - A review on the effects of combined stress cracking defects in steels
  Reza Navidnezhad Shahram Shahrooei Erfan mirshekari Pejman Taghipour birgani
  Stress cracking is an important threat to steel industries. When certain conditions are created in the environment of steel, the loading of this defect leads to intergranular cracks in the radial-axial plane. These cracks can grow under continuous adverse loading and ev More

  Stress cracking is an important threat to steel industries. When certain conditions are created in the environment of steel, the loading of this defect leads to intergranular cracks in the radial-axial plane. These cracks can grow under continuous adverse loading and eventually lead to rupture. A lot of research and experiments have been done in this regard. This article is a review of the combination of conditions governing steels that lead to the growth of stress cracking. Failures caused by stress cracking occur in a long period during several stages such as germination, crack growth and final failure. On the other hand, we know that stress cracking depends on environmental, metallurgical and mechanical conditions. Therefore, in this article, the purpose of investigating the loading conditions at each stage of stress cracking and the effects of repetitive stress on steels will be discussed. Also, the synergistic effects of different parameters during the entire life cycle of steels will also be discussed. The main focus of this review is to relate the loading conditions at each stage of crack propagation, which plays an important role in estimating the remaining life of steels susceptible to stress cracking. This discussion will include how cyclic loading conditions can change steel properties and contribute to the initiation of intergranular cracking. Finally, the modeling of stress crack growth will be discussed and suggestions such as failure analysis due to stress crack growth on sheets were given. Manuscript profile
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  3 - Correction and improvement of the vibrations of air fans by increasing the Stiffness and changing the natural frequencies of the structure
  erfan mirshekari Bahman Poormohamad
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