Flywheel sizing and analysis of coefficient fluctuation based on the crank kinematic free response to a torque pulse input.

The present paper proposes a method for evaluating the change in the kinematic free response for a torque pulse input in mechanisms and mechanical systems. Therefore, two generic four-bar mechanisms were analysed, doing the initial flywheel sizing based on the energy variations in one revolution of the system by a developed method of integration and stipulating a coefficient of fluctuation in the recommended intervals. The changes in the angular velocities were obtained by the power spectral density (PSD) with Welch's method, varying the number of points of the fast Fourier transform (NFFT), evaluating the magnitude (PSD) and frequency changes by a created C-coefficient, considering both. For coefficients close to the natural, no relevant frequency change was observed, compared with the magnitude changes, also noting that the C-coefficient changes exponentially when it is distant from the natural value, without flywheel. Significant changes were computed showing the sensitivity of the method, stabilising with the increase of the NFFT. For the integration method for flywheel sizing, a good result was obtained with small angle steps and small torque curves, obtaining an error of 0.00001 in the case of study. [ABSTRACT FROM AUTHOR]