تحليل ديناميكي و آناليز ارتعاشي تغذيه كننده هاي ارتعاشي كاسه اي

چكيده انگليسي :

Dynamic and Vibration Analysis of Vibratory Bowl Feeders Sayed Hossein Ashrafizadeh Email sh ashrafizadeh@me iut ac ir Date of submission February 2 2 Department of Mechanical Engineering h d 6 nDegree M Sc Language Farsi Supervisor Saeed Ziaei Rad Email szrad@cc iut ac irAbstractVibratory bowl feeders are among the most versatile machines used for the feeding of small elements during theassembly process The feeding element in a vibratory bowl feeder moves forward with sliding or hoppingmovement There are two parameters that have great influence on the performance of a vibratory bowl feeder The first parameter is the vibration angle which is the angle between the track and its vibration direction Secondparameter is the bowl feeder natural frequencies and their related mode shapes These parameters affect theelements feeding speed and define the optimum inducing frequency in which the minimum energy would bewasted In the first section of this MSc thesis finite element method was utilized for vibration and modal analysisof a vibratory bowl feeder In order to validate the model some experiments were performed and good agreementbetween the simulation data and experimental data was obtained It is shown that the vibration angle is notnecessarily equal to the complementary of the spring inclination angle The effect of some physical parameterssuch as spring thickness support stiffness and bowl mass on vibration angle and the main natural frequency ofthe vibratory bowl feeder has also investigated The second part of this MSc thesis focuses on the elementsdynamics during the feeding process in a vibratory bowl feeder The feeding elements in a vibratory bowl feederare experiencing repeated impacts with friction In order to model the behavior of the elements a 2D numericalmodel based on discrete element method has been developed using C computer language In contrast to previousresearches it is assumed that the feeding element is not a point mass and has a rectangle shape that can rotate andhave three degrees of freedom This model is capable to demonstrate both the periodic and chaotic behavior ofthe feeding elements By performing the simulation for various vibration amplitudes good agreement wasobserved between calculated data with the experimental data reported in the literature The effect of vibrationamplitude element shape coefficient of friction and track angle on mean conveying velocity was evaluated andthe results are presented This model is also capable of simulating interactions between the feeding elements andit was found that the elements interactions speed up the process as the elements would climb up the track easierdue to the push forces of the back elements Although this 2D model seems to be an appropriate model forsimulation of the feeding elements in a vibratory bowl feeder it is incapable of comprising the effect of Coriolisacceleration and the contacts with the wall of the bowl To this matter a 3D model based on discrete elementmethod has also been developed and the dynamic of a 3D element with six degree of freedom which is movingon the track of the bowl has been investigated It is shown that this 3D model is capable to demonstrate both theperiodic and chaotic behavior of the feeding element too By performing the simulation for various vibrationamplitudes a good degree of agreement observed between calculated and experimental data reported in theliterature Using this 3D simulation it is shown that due to the unsymmetrical forces the element rotates as itmoves forward on the track It is also demonstrated that the Corioilis acceleration affects the radial position of themoving element The most advantage of this 3D model is its capability in explaining the reason of existence oftwo maximums in the experimental graph of mean conveying velocity versus vibration amplitude Keywords Vibratory bowl feeder vibration angle finite element method mean conveying velocity chaoscontacts discrete element method Coriolis acceleration

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تحليل ديناميكي و آناليز ارتعاشي تغذيه كننده هاي ارتعاشي كاسه اي

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