Comparative study of vibration-absorbing materials to improve the comfort of the crew on a river ship

The purpose of this paper is to find a damping material for the vibrations generated by the equipment of a ship. That will improve the working and resting conditions of seafaring personnel on a pusher boat that travels over long distances. The experiments were made upstream the Danube. The convoy was made up of a self-propelled vessel and four barges. The water flow rate was 0.76 m/s and there were good visibility conditions and light wind. The accelerations transmitted to man were measured with Seat PAD 01dB triaxial accelerometers mounted on the floor of the ship and connected to the NetdB-Complex system for analysis and measurement. The working frequencies were 0÷100 Hz. Subjects were placed directly on the ship's deck, then on neoprene and rigid foam. It was found that for longitudinal vibrations, the r.m.s. accelerations are 9 times higher than standard if there is no attenuator, 4.8 times higher than standard for neoprene and 2.4 times higher in the case of rigid foam. For transverse vibrations, r.m.s. accelerations are 10.8 times higher than standard when there is no attenuator, 6.4 times higher in the neoprene case and 2.7 times higher for rigid foam. For vertical vibrations, accelerations r.m.s is 5.9 times higher than standard if there is no attenuator, 3.4 times higher for neoprene and 1.7 times higher for rigid foam. The results are similar in the case of transmissibility determination. It was shown the importance of a vibration attenuator for the health, comfort and implicitly for labour productivity of river sailing personnel. (paper)