リング状動吸振器によるチゼル打撃音抑制に関する研究

抄録

Hydraulic breakers make a loud noise during demolishing concrete structures or rocks, etc. It is considered that one of the major sources of the noise is the longitudinal vibration resonance of a chisel of the breakers. Hence, in order to suppress the noise, a chisel which a dynamic damper is integrated is proposed in this paper. The dynamic damper consists of ring-shaped weight and ring-shaped plastic spacers. To install the dynamic damper, a portion of the chisel must be made slender because the diameter of the chisel is limited considering attaching to the breakers. The resonance frequencies of longitudinal vibration modes of the chisel are changed with parameters of the dynamic damper, such as size and position, etc. Therefore, it is difficult to design the dynamic damper with conventional ways. First, response of the proposed chisel vibration is derived with the transfer matrix method theoretically. Second, experimental results of the frequency response are shown and confirm the validity of the theoretical model. Then, effects of the parameters of the dynamic damper are investigated with the model. Finally, the experimental results are shown, which sound noises were measured when the chisels were impacted with a breaker. These results show that the proposed chisel is valid and feasible for reducing the noise from Hydraulic breakers.