Authors: Bruno Augusto, Pedro Menezes, Pedro Campos, Pedro Camacho, Rafael Dias, Tomás Carneiro, Nuno Ramos, Mário Vaz

This article aims to present the results of the analysis of mechanical vibrations carried out in one of the lawn-mowing tractors of the Faculty of Engineering of the University of Porto, as well as all the preparation and experimental procedure that gave rise to them. The theme of mechanical vibrations is omnipresent and there are decree-laws and regulations governing the exposure of the human body to them. Based on this assumption, portuguese and international standards were analyzed as to generate a valid analysis of vibrations. These were measured in the hand-arm and whole-body system. Resorting to accelerometers, an experimental procedure was created. This was carried out and the results were treated in MATLAB®. For this purpose, scripts were created to convert the acceleration data obtained into the frequency domain through a Fast Fourier Transform. Then, the acceleration amplitude was discretized according to third octave bands depending on the place where it was measured. Using the adequate weighting factors, the total acceleration values were obtained. The results show that the vibrations to which the operator is subjected are within legal limits. However, they are considered to be somewhat uncomfortable, according to the standard's classification. From a safety standpoint, the study emphasizes the importance of vibration analysis in work operations for operator comfort and safety.

Bruno Augusto¹ | Pedro Menezes¹ | Pedro Campos¹ | Pedro Camacho¹ | Rafael Dias¹ |Tomás Carneiro¹ | Nuno Ramos¹ |Mário Vaz¹
1 LOME, INEGI, Faculdade de Engenharia da Universidade do Porto (FEUP), Portugal