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International Journal of Advanced Design and Manufacturing Technology
   [5 followers]  Follow    
  This is an Open Access Journal Open Access journal
     ISSN (Print) 2008-1421
     Published by Islamic Azad University Homepage  [7 journals]
  • Vibration Analysis of Laminated Composite Plates Carrying Rotating
           Circular Mass

    • Authors: Reza Alibakhshi, Reza Akbari Alashti
      Pages: 1 - 9
      Abstract: In this paper, the free vibration response of a laminated composite rectangularplate supporting a rotating circular patch mass is studied. The two variable refined platetheory that employs only two unknown functions as against three in the case of simpleshear deformation theory is applied to define the third order displacement field of acomposite rectangular plate. The plate is considered to have simply supported boundaries.The equations of motion for the rectangular plate are obtained by calculus of variation. Dueto significance of the fundamental frequency of the plate, its variation with respect to thenon-dimensional geometrical parameters such as aspect ratio of the plate, size and locationof the rotating patch mass, is investigated. It will be shown herein that the proposed theoryis simple in solving the free vibration problems of plates with patch masses.
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • Optimization of suspension system of sport car in three dimensional
           reactions space

    • Authors: Reza Kazemi, Mohsen Raf'at, Hadi Zolghadr
      Pages: 11 - 18
      Abstract: Suspension system as one of the most important key elements of vehicle has always been considered by research centres and auto makers over the world and this issue is more important on sport cars which have special sensitive working conditions and even the smallest defect can strongly affect their performances. In this study, optimization of effective handling parameters of a sport car with three optimization indices is favourable cover racetrack at the shortest possible time. For this purpose a sport car model simulated in ADAMS/car software has been used and all test steps have been implemented in this environment. At the end of reaching optimum solution in different racetrack conditions, Pareto solution set optimization method has been used and in this problem, optimization indices have been examined which is covered distance in standard constant radius test with three different radii. so, by implementation of these experiments at different levels of optimization parameters, all solution sets are collected in a three dimensional diagram called performance space whose coordinates axes are optimization indices values, then using LP norm idea, possible optimum solutions are selected from among other solution and in order to find optimum solution in a special racetrack, a new idea has been proposed, through this, weighted coefficients related to each optimization indices for a special racetrack are determined and optimum solutions appropriate for that track is selected from pareto solution set.
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • Effects of Scan Direction and Orientation on Mechanical Properties of
           Laser Sintered Polyamide-12

    • Authors: Jack A Nelson, Greg Galloway, Allan E W Rennie, Tom N Abram, Graham R Bennett
      Pages: 19 - 25
      Abstract: In order to understand the impact of layer-wise scanning direction in the Selective Laser Sintering process, test coupons were manufactured for mechanical testing from DuraForm™ Polyamide powder. The effects of laser energy density, varying between 0.003 and 0.024 J/mm2 were examined in test specimens rotated 90º through the Z axis. SLS machines do not always facilitate ‘cross-hatching’ of layers and therefore orientation has a major influence on part quality. When employed, the cross-hatching technique scans successive layers perpendicularly to the previous. Studying how parts perform with scan lines in a common direction, will assist in the understanding of how SLS parts behave in practice. Results showed that physical density, tensile strength and elongation rose with energy density up to 0.012 J/mm². This initial rise was due to a continued improvement in particle fusion with increasing energy density. Above 0.012 J/mm², these properties started to decline at different rates depending on their orientation (scan direction) on the part bed. Specimen’s oriented perpendicularly to the X axis exhibited a greater elongation at the expense of tensile strength, when compared to parallel specimens.
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • A Finite-Volume Method in General Curvilinear Coordinates for Simulation
           of Blood Flow Past a Stenosed Artery

    • Authors: Sina Zanousi, Ruzbeh Shafaghat, Qadir Esmaili
      Pages: 27 - 36
      Abstract: In this study, flow characteristics through symmetric stenosis artery are investigated. The shape of eccentricity for stenotic flows is limited by circular-cross sections and plaques are usually assumed as to be oriented concentrically. ThegoverningequationsaretheusualNavier-Stokesequationsandare numericallysolved by using finite volumemethod in arbitrary orthogonal curvilinear coordinates. In addition, three-dimensional elliptic grid is presented which the generating system is based on solution of a system of partial differential. To prevent serious distortion or overlapping of mesh lines, grid regularity is verified by some controlling parameter like Skewness value and maximum grid aspect ratio (MAR).The main objective of the present study is to investigate different degrees of the stenosis (45%, 55%, 65% and 75% by area reduction) and finding the critical one which play a significant role in the development of forming sediment in the wall of vessel. It is shown that the magnitude of inlet Reynolds number have strong relationship with the velocity, pressure and wall shear stress (WSS) distributions as expected. The most important conclusion obtained from our model is the high WSS and pressure drop which is exerted near the stenosed point and formation and development of large recirculation regions which found in the downstream of the stenosis, especially in the case of severe stenosis could create many pathological diseases
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • Analytical Investigation of Rupture Phenomena in Sheet Hydro-forming
           Process by Hemispherical Punch

    • Authors: Alireza Naddaf Oskouei, Mohammad Reza Elhami, Iman Karami Fath
      Pages: 37 - 43
      Abstract: Rupture and wrinkling are two prevalent phenomena that happen in hydro-forming process. Many efforts have been made to achieve the upper and lower bounds for the pressure related to rupture and wrinkling of sheet, respectively. The aim of this investigation is to improve the upper bound of fluid pressure in hydro-forming process by hemispherical punch. In this article, analytical study of the upper bound of fluid pressure based on new assumption of Hill theory is presented. Next, governing equations of the process is derived; and numerical methods are used to solve these equations. In this process, the effect of material and geometric properties on the upper bound pressure is investigated. The results then are compared with experimental and theoretical based on Tresca criterion. The investigation on the effect of geometry and material shows that increasing of the sheet thickness raises the upper bound pressure. Moreover, the reduction of sheet to punch diameter ratio leads to increase of the upper bound pressure. Decrease of the friction force as well as increase of the anisotropic coefficient both causes the rise of upper bound pressure. Finally, the increase of work hardening parameter leads to the rise of rupture place.
      PubDate: 2014-11-16
      Issue No: Vol. 7, No. 3 (2014)
       
  • Faults diagnosis of a girth gear using discrete wavelet transform and
           artificial neural networks

    • Authors: Mahmuod Akbari, Hadi Homaei, Mohammad Heidari
      Pages: 45 - 55
      Abstract: In this paper, a fault diagnosis system based on discrete wavelet transform (DWT) and artificial neural networks (ANNs) is designed to diagnose different types of fault in gears. DWT is an advanced signal-processing technique for fault detection and identification. Five features of wavelet transform RMS, crest factor, kurtosis, standard deviation and skewness of discrete wavelet coefficients of normalized vibration signals has been selected. These features are considered as the feature vector for training purpose of the ANN. A wavelet selection criteria, Maximum Energy to Shannon Entropy ratio, is used to select an appropriate mother wavelet and discrete level, for feature extraction. To ameliorate the algorithm, various ANNs were exploited to optimize the algorithm so as to determine the best values for ‘‘number of neurons in hidden layer” resulted in a high-speed, meticulous three-layer ANN with a small-sized structure. The diagnosis success rate of this ANN was 100% for experimental data set. Some experimental set of data has been used to verify the effectiveness and accuracy of the proposed method. To develop this method in general fault diagnosis application, an example was investigated in cement industry. At first, a MLP network with well-formed and optimized structure (20:12:3) and remarkable accuracy was presented providing the capability to identify different faults of gears. Then this neural network with optimized structure is presented to diagnose different faults of gears. The performance of the neural networks in learning, classifying and general fault diagnosis were found encouraging and can be concluded that neural networks have high potential in condition monitoring of the gears with various faults.
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • Engineering Design of the Guidance System of the 6R Tele-robot based on
           DTMF

    • Authors: Moharam Habibnejad
      Pages: 57 - 63
      Abstract: In this article, the advantages of navigation based on dual tone multiple frequencies (DTMF) technique through telecommunication lines is studied. First, the calculations of direct and inverse kinematics of the manipulator in computer are transferred to the PIC microprocessors center. Next, each PIC is required to control and automate the relevant link separately. The main purpose of this work is making it possible to control the robot via a telephone line and without a modem. In order to apply this idea, computer is analyzed the data which received from the operator and insert the necessary instructions through the serial port using AVR microcontroller in the embedded hardware at the phone line and sends them to the hardware of the robot. Then the robot is performed the processes as a closed loop design and provides the necessary feedback for the computer. Real-time control, low volume of software and hardware computations and the possibility of using the phone lines with low and medium bandwidth in addition to ADSL lines simultaneously are the special features of this method. In the proposed method, control data and the corresponding feedbacks are transmitted as the remote closed loop control, which can be combined in the developing stages with other control methods such as neural networks which results the maximum productivity. At the end of this work, examination of the time delay of tele-controller system and experimenting according to the ISO9283 standard, specific to the accuracy of the robot, is carried out.
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • The application of Imperialist Competitive Algorithm to optimization
           problems arising in welding process

    • Authors: Seyed Adnan Adnani Salehi
      First page: 65
      Abstract: The Imperialist Competitive Algorithm (ICA) that was recently introduced has shown its good performance in optimization problems. This algorithm is inspired by competition mechanism among Imperialists and colonies, in contrast to evolutionary algorithms. This paper presents optimization of bead geometry in welding process using of ICA. Therefore, two case studies from literature are presented to show the effectiveness of the proposed algorithm. ICA has demonstrated excellent capabilities such as simplicity, accuracy, faster convergence and better global optimum achievement. The results of ICA were finally compared with the Genetic Algorithm (GA). The outcome shows the success of ICA in optimizing the weld bead geometry.
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • Developments in Conventional Machining of Aluminum matrix Composite
           material: A review

    • Authors: VINOD KUMAR SAINI
      First page: 73
      Abstract: Aluminium matrix composites (AMCs) materials are continuously displacing traditional engineering materials because of their advantages of high stiffness and strength over homogeneous material formulations. Properties of AMCs can be tailored to the demands of different industrial applications by suitable combinations of matrix, reinforcement and processing route. Presently, several grades of AMCs are manufactured by different methods. The hard ceramic component that increases the mechanical characteristics of AMCs causes quick tool wear and premature tool failure in the machining operations. Therefore the solution of the machining problems is one of the prerequisites for a widespread industrial application of AMCs. This paper provides a review of various research activities and various developments in the field of conventional machining of AMCs. Researchers have explored a number of ways to improve machining efficiency by traditional methods. This paper presents an overview of AMC material that reveals the roles of the reinforcement particles on the machinability of AMCs and provides a useful guide for a better control of their machining processes.

      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
  • DESIGN AN ARTIFICIAL ANKLE USING SERIES ELASTIC ACTUATOR

    • Authors: Ali Moazemi goudarzi, Hossein Kheirollahi, Mohammad Fazeli, Misagh Imani
      First page: 83
      Abstract: : Investigating the mechanical behaviour of a healthy human ankle shows that it can be simulated by a mechanism composed of simple elements such as spring, and actuator. Hence, appropriate design of this mechanism can be resulted to an artificial ankle that can help amputees properly. Researches show that whatever the biomechanical behaviour of artificial ankle is similar to that of natural ankle, it can be used by consuming less energy. Considering biomechanical behaviour of normal ankle in a walking gait, required parameters for designing of an artificial ankle composed of springs and electromechanical actuator will be determined. Finally, to verify the suggested model, a prototype will be materialized and tested.
      PubDate: 2014-11-15
      Issue No: Vol. 7, No. 3 (2014)
       
 
 
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