Alberto Tamagna

Evaluation of the Vibratory Effect Transmitted by Road Buses Bodyworks

The objective of this work is to evaluate the levels and vibratory effects that the passengers who use intermunicipal road buses are submitted. In the study, measurements of the accelerations produced in the vertical direction had been carried through according with norm ISO 2631, in two bus bodyworks, of different manufacturers, in a normal situation of use, in three points of it (frontal, central and back). With the measurements it was possible to point which are the places in the bodywork interior and the points in the seats that produce greater accelerations r.m.s. The results had been evaluated and compared with the curves values established for norm ISO 2631 in relation to health and comfort and in relation to fatigue, comparing the two tested bodyworks.

Sound reduction by simple walls of brick and concrete

Sound insulation can be difficult to forecast. In most cases it is necessary to take certain precautions in order to avoid degradation in the acoustical performance of walls. Knowing that sound transmission through walls depends on mass per unit area, bending stiffness, damping, mounting conditions, frequencies, etc., the sound transmission can be explained theoretically by several hypotheses. Even though sound transmission has been investigated for more than 100 years, there still remain a lot of issues to be solved. The purpose of this work is to present a discussion regarding the main analytical models used in sound reduction by simple walls, to help the engineer in noise control projects for industry or homes. Several model cases were analyzed by numerical estimation, and the best results were selected to perform experimental comparisons. Some comparative graphics are presented to compare numerical and experimental results. [Work supported by CAPES.] (To be presented in Portuguese.)