Reduction of Watercrafts Vibroacoustic Activity by Vibration Damping Materials

Abstract

   Introduction. Electric machines, diesel installations, pumping units and fans, as well as working bodies of dredgers (pipelines, scoops, rippers, etc.) are the main sources of noise and vibration on watercrafts. Moreover, the main harmful factors in the operation of floating cranes and dredgers are both the vibration itself and the accompanying phenomena of infrasound and structural noise. One of the most urgent tasks for the introduction of technosphere safety methods on watercrafts is to reduce the harmful effects of vibroacoustic factors on the health of personnel.   The research objective is to improve the working conditions of watercrafts drivers by introducing the method of designing vibration protection systems proposed by the authors, taking into account both the external factors (ambient temperature) and the dynamic characteristics of vibration damping materials.   The possibility of choosing the most rational vibration damping material based on the engineering calculation of the required vibration insulation is shown.   Materials and Methods. A passive method of vibration control has been applied, in which elastic elements and vibration damping material are used in the watercraft design. The sources of noise and vibration have been identified, and their actual exposure levels have been determined. The analysis of dynamic characteristics and properties of vibration damping materials is carried out. The factors influencing the efficiency of vibration damping are revealed.   Results. A design scheme of the vibration damping model at the workplace of the watercraft driver has been developed. An analytical database of dynamic characteristics and properties of vibration damping materials has been created. An engineering method for calculating the effectiveness of vibration insulation has been adapted to watercrafts. The calculations of the effectiveness of vibration insulation using various vibration damping materials of different thicknesses have been performed, on the basis of which the advantages of vibration damping flooring made of elastomeric plate VEP20 have been proved.   Discussion and Conclusion. The engineering methodology developed in Excel for calculating the effectiveness of vibration insulation is automated and has a user-friendly interface. This allows you to calculate and reasonably select multilayer structures taking into account the ambient temperature, as well as the dynamic characteristics of vibration damping materials depending on the spectrum of noise and vibration. The results obtained can be used in the design of vibration protection systems for watercraft drivers.