Proposta e modelagem de uma bancada didática para ensino de manutenção mecânica por monitoramento da vibração

Abstract

Breaking of machinery and equipment creates loss to the industry, but, through predictive maintenance, It can be avoided before it happens. The goal of this work is to propose a mechanical model of a didactic bench for teaching mechanical maintenance by monitoring the mechanical vibrations, performing the simulation of damage conditions and monitoring the system via bathtub curve. The test bench proposed is composed from a motor, a reduction by a pair of gears and a inertia disk, and the mathematical model created for it has 6 degrees of freedom, they are the vertical displacement from the motor and the inertia disk, and both vertical and angular displacements for both reduction shafts. The model was solved to find the system’s transfer functions, with the simulations being made over the function that relates the vertical acceleration measured in the bearing closest to the motor in the input shaft of the reduction, and the force created by the motor’s unbalancement. As the work is theoretical and there are no experiments and data of a real test bench, the Bode magnitude plot of the function is used as frequency spectrum of the test bench, and the simulations were done using MATLAB, applying an harmonic input to the transfer function. Many simulations were made applying diferente conditions of stiffness loss in one of the system’s spring-dumper pairs, the one that represents the connection between the motor and the reductor, to simulate the manifestation and development of damage and later its repair. The data from those simulations were considered real data, applying the maintenance principles to detect and correct mechanical faults. The results show that the model is appropriate for use in the theoretical class, but its parameters would need adjustment through experimentation in a real test bench for model validation.