فهرست مطالب

  • Volume:12 Issue: 4, 2020
  • تاریخ انتشار: 1399/03/29
  • تعداد عناوین: 5
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  • Ata Jahangir Moshayedi *, Li Jinsong, Liefa Liao Pages 5-18

    The AGV (automated guided vehicle) was introduced in UK in 1953 for transporting. But nowadays, due to their high efficiency, flexibility, reliability, safety and system scalability, they are used in various application in industries. In brief, the AGV robot is a system which typically made up of vehicle chassis, embedded controller, motors, drivers, navigation and collision avoidance sensors, communication device and battery, some of which have load transfer device. In this review paper, based on existing systems, the AGV structures are studied and compared from various point of view and analysis of the AGV structure is done for design. The AGV (automated guided vehicle) was introduced in UK in 1953 for transporting. But nowadays, due to their high efficiency, flexibility, reliability, safety and system scalability, they are used in various application in industries. In brief, the AGV robot is a system which typically made up of vehicle chassis, embedded controller, motors, drivers, navigation and collision avoidance sensors, communication device and battery, some of which have load transfer device. In this review paper, based on existing systems, the AGV structures are studied and compared from various point of view and analysis of the AGV structure is done for designer.

    Keywords: AGV, Robotics, automated guided vehicle
  • Mostafa Karimi *, Alireza Hassani Pages 19-40

    In this paper, the solution of an isotropic hollow cylinder, with an isotropic coating, weakened by multiple radial cracks is studied. The hollow cylinder and its coating are under SaintVenant torsional loading. The series solution is then derived for displacement and stress fields in the cross section of the cylinder containing a Volterra-type screw dislocation. The dislocation solution is employed to derive a set of Cauchy singular integral equations for the analysis of multiple curved cracks. The solution to these equations is used to determine the torsional rigidity of the domain and the stress intensity factors (SIFs) for the tips of the cracks. Finally, several examples are presented to show the effect of the coating on the reduction of the mechanical stress intensity factor in the hollow cylinder.

    Keywords: several cracks, Stress intensity factor, Distribution dislocation technique, Torsional rigidity
  • Hojjat Ashouri * Pages 41-51

    This paper presents low cycle fatigue (LCF) life prediction of a coated and uncoated exhaust manifolds. First Solidworks software was used to model the exhaust manifolds. A thermal barrier coating system was applied on the tubes c of the exhaust manifolds, consists of two-layer systems: a ceramic top coat (TC), made of yttria stabilized zirconia (YSZ), ZrO2-8%Y2O3 and also a metallic bond coat (BC), made of NiCrAlY. The temperature-dependent of material parameters was considered in order to increase the accuracy of LCF life results. Then Ansys Workbench software was used to determine stress and fatigue life based on Morrow and Smith-Watson-Topper (SWT) approaches. Thermal fatigue failure of the engine components easily happens due to excessive temperature gradient and thermal stress. Modern exhaust systems must withstand severe cyclic mechanical and thermal loads throughout the whole life cycle. The results of finite element analysis (FEA) showed that the thermal barrier coating system reduces the temperature about 29°C because of its lower thermal conductivity. As a result, the exhaust manifolds tolerates lower temperature and fatigue life will increase. The results of thermo-mechanical analysis indicated that the stress in the coated exhaust manifolds decreased approximately 25 MPa for the sake of depletion of temperature gradient which can lead to higher fatigue lifetime. The results of LCF proved that the number of cycles of failure for coated exhaust manifold is approximately in the order 2-fold longer, than the results obtained from the uncoated exhaust manifolds.

    Keywords: low cycle fatigue, Morrow, SWT approaches, exhaust manifolds, thermal barrier coating, confluence cracks
  • Ata Jahangir Moshayedi *, Atanu Roy, Liefa Liao Pages 53-66
    Controlling a system can be done in various ways and methods. The classical method which even now a day as a solution works is PID which in that with some method three-parameter of controller called P (Proportional), I (Integral), D (Derivational) tuned to have the best controlling response from a system. The AGV robot as the abbreviation of the Automated Guided Vehicle is as a famous robot platform which used in various industries relies on PID controllers in various ways. Each AGV or Machine has its own set of function, hence, in order to accomplish the exact set of workload more efficiently one need to actually tune the PID parameters accordingly so that there cannot be an intolerable amount of energy loss, inefficiency rate, lag, lack of robustness etc. In this paper over than introduction of PID controller and see the effect of each parameter on the real system the compassion between hired methods on AGV robot are investigated. As this review indicates that various PID tune method are used based on system requirements with the help of Lyapunov Direct Method, traditional Ziegler Nichols, Fuzzy controller, human immune system called the humoral, neural network, etc to control the speed and steering of an AGV systems.
    Keywords: PID, AGV, PID Tune, Ziegler-Nichols, automated guided vehicle
  • Saeed Alibabaei, Masoud Kasiri-Asgarani*, HamidReza Bakhsheshi-Rad Pages 67-79

    In this study, the effect of heat treatment on the corrosion properties of Mg-Zn-RE-xCa alloy (x = 0, 2.5) was investigated. These alloys were produced using an argon atmosphere casting process and then subjected to vacuum conditions at 400 C for 6 hours under solid solution treatment and quenching in water. The microstructure and fuzzy analysis of heat treatment alloys using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) were investigated. Immersion, polarization, impedance, and pH changes test were performed to study alloy corrosion behavior. The results showed that in heat treated samples, the values of secondary phases IM1 (Ca3MgxZn15-x) (4.6 ≤ x ≤ 12) and Mg2Ca increased with increasing calcium content. However, the amount of these phases is reduced by dissolution and quenching in water. The corrosion density of alloy is reduced by adding 2.5% calcium from 488.4 to 315 μA / cm2, which decreases to 126.5 μA / cm2 after 6 hours of heat treatment, indicating improved corrosion resistance of the alloy after heat treatment.

    Keywords: Magnesium, Solution Thermal Operations, Biodegradability, Corrosion