抄録
Paper-based electrostatic power generators are being developed to supply low-power consumption and electrostatically induced electric power conversion from environmental noises in the same device. The purpose of this research is to clarify the relationship between vibration damping and the mechanical properties of paper in order to realize efficient power generation by preventing vibration damping. Vibration damping was evaluated by measuring the sound power level of acoustic waves traveling through various types of commercially available paper in the thickness direction. The resulting sound power level was not related to the in-plane specific Young's modulus of paper. However, it decreased with increasing paper thickness because longitudinal waves being transmitted through paper lose vibration energy along the traveling distance because of compression in the thickness direction. Furthermore, laboratory sheets were subjected to concurrent measurements of the sound power level and in-plane Young's modulus with an ultrasonic tester. The in-plane specific Young's modulus was confirmed to be a key parameter affecting the sound power level for the laboratory sheets because the propagating surface waves travel in the in-plane direction and they were transverse waves with in-plane compression. Regarding papermaking materials, there was no difference in vibration damping tendency between hardwood and softwood bleached kraft pulps.
