Maistruk Pavlo Volodymyrovych. Synthesis of discrete-continuous inter-resonance oscillating system of the vibrating machines with an electromagnetic drive. – Qualifying scientific hearing on the rights of the manuscript.
The dissertation on competition of an educational and scientific degree of the doctor of philosophy (PhD) on a specialty 131 – Applied mechanics. Lviv Polytechnic National University, Ministry of Education and Science of Ukraine, Lviv – 2023.
Taking into account the need to introduce energy-efficient technologies in the field of mechanical engineering, the introduction substantiates the relevance of further scientific research during the creation of highly efficient vibrating technological equipment. Common single- and two-mass mechanical oscillating system (MOS) do not allow the maximum realization of the dynamic potential of vibrating machines. Existing three-mass vibrating machines capable of operating in highly efficient inter-resonance modes of operation have a number of disadvantages associated with their implementation as industrial equipment. It has been established that the research, design, and implementation of new highly efficient designs of vibrating machines, and the creation of new methods of their calculation is an actual issue of scientific research in the field of vibration technology, for the solution of which the aim and task of further theoretical and experimental research were formed in the dissertation.
In order to find promising solutions in the field of implementation of high-efficiency vibrating machines, an analysis of modern trends in the development of vibrating technological equipment was carried out, in particular, single-mass, two-mass, pseudo-three-mass and three-mass inter-resonance MOS were compared. Their designs and modes of operation during operation in the industry are described. It has been proven once again that three-mass inter-resonance MOS are the most suitable structures for the implementation of highly effective modes of operation of vibrating machines.
The dissertation analyzed the existing three-mass vibration machines with the most common types of drive: inertial, crank, and electromagnetic. Based on a review of the design and principle of operation of a highly efficient three-mass inter-resonance vibrating conveyor-separator with a crank mechanism combining both discrete and continuous structures, the promising nature of the proposed hybrid MOS was noted.
At the same time, some disadvantages of using crank mechanisms as a drive of vibrating machines are highlighted, including the presence of movable joints that reduce the reliability of these structures, and the complexity of the process of starting this type of vibrating technological equipment. It was determined that the use of three-mass inter-resonance vibration machines with an inertial drive also has a number of disadvantages, in particular, the difficulty of entering the inter-resonance zone of oscillations and the impossibility of obtaining an ultra-light reactive mass to ensure high energy efficiency of operation. The existing samples of three-mass vibrating machines with an electromagnetic drive are considered and the feasibility of using this type of drive for the implementation of highly efficient modes of operation is substantiated.
Based on the analysis of literary sources, the idea of further dissertation research was formed, which consists of the application of continuous members with distributed parameters in discrete MOS of vibrating machines with an electromagnetic drive. The hypothesis that ensures the implementation of this idea comes down to the introduction of a continuous member in the form of a plate into a discrete MOS, which has small inertial and stiffness parameters and allows the electromagnetic drive to effectively disturb this system.
As the first stage of the description of the discrete-continuous MOS of the vibrating table with an electromagnetic drive, a reference discrete model of the three-mass MOS was formed. The inertial, stiffness, and power parameters of the reference discrete three-mass system were established, and its energy efficiency was determined in comparison with the two-mass MOS. Graphs of amplitude-frequency characteristics of discrete oscillatory systems were obtained.
According to the proposed concept of designing a discrete-continuous MOS of a vibrating machine with an electromagnetic drive, a schematic diagram of a discrete-continuous inter-resonance MOS was developed and proposed a constructive solution for fastening the continuous member in the intermediate mass. A calculation scheme for fixing the plate has been created. The plate is symmetrically fixed with the help of four hinged supports located along its perimeter. At the same time, the continuous member can be divided into two consoles and the middle.
