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The analysis of critical speeds of elastic shafts considering gyroscopic effect is performed by the transfer matrix method. A transfer matrix is formulated for free vibration without damping and forced vibrations with damping. A rotor-motor-pump model is analized with both the Finite Element Method (FEM) and Transfer Matrix Method (TMM) to compare and validate the approach. The gyroscopic effect influences in the resonance frequency is analysed.

This study presents a comparison of three methods: VC4000PC accelerometer, Sensor Kinetics mobile app, and video analysis by Tracker (free software). The methods have been compared experimentally for emergency braking with locked wheels, as well as using the antilock braking system (ABS). Data from the three methods were recorded simultaneously. Data analysis was made, applying inferential statistics. The results from the analysis of variance (ANOVA) and precision analysis indicate that data collected with the smartphone app ensures good accuracy and does not provide significant differences in comparison with the accelerometer, while the video analysis method showed some statistical differences. The regression analysis yielded an estimation coefficient R2 close to 1, and a residual standard error (RSE) being almost 0, for all experiments, parameters that indicated a good linear regression for both low-cost methods as a function of the accelerometer.