Xylophones are fabricated using valuable tropical hardwood. Considering the effect of xylophone shape on flexural vibration, we examined the possibility of using hardwood from Satoyama as a substitute material for tropical hardwood. Focusing on the first-, third-, and fifth-order flexural vibration modes, we compared rosewood and Satoyama hardwood in terms of the ascending vibration region and the damping behavior thereafter. The first, third, and fifth flexural vibrations are excited immediately after the start of the vibration, and the third and fifth vibrations disappeared immediately. The amplitude of the third vibration exceeds that of the first vibration and is 1.5 to 2 times larger in the xylophone-shaped bar. The amplitudes of the fifth vibration of the rectangular and xylophone-shaped bars are approximately 1/4 and 1/2 of that of the first vibration, respectively. The logarithmic decrement in the first vibration of rosewood is less than that of Satoyama hardwood, and rosewood cannot be replaced easily with Satoyama hardwood to achieve the desired vibration damping.

The purpose of this study was to clarify the effect of differences in wooden floor materials on walking with socks on. We conducted a walking experiment in four different model floors combining two types of floor finishing materials and two types of subflooring materials and a control floor (vinyl floor over the concrete subfloor) using surface electromyography of the lower limb and plantar pressure distribution as physiological indicators. It was found that the surface consolidated Japanese cedar, sugi (Cryptomeria japonica) wood finishing, which is uneven and non-slip, has smaller ratio of integrated electromyography (ratio of the integrated surface electromyogram for each model floor to the integrated surface electromyogram for the control) than the ceramic-coated Japanese cypress, hinoki (Chamaecyparis obtusa) wood finishing, which is smooth and slippery, and reduces the burden on the lower limbs during walking. The difference between the finished materials under the low-stiffness joist and 15-mm-thick plywood subflooring condition was smaller than under the high-stiffness 24-mm-thick plywood subflooring condition, indicating that the stiffness of the subflooring material has a secondary effect on the ratio of integrated electromyography. In the plantar pressure distribution, the ratio of entire plantar load to control was significantly higher for the surface consolidated Japanese cedar wood finishing under the joists and 15-mm-thick plywood subflooring condition, indicating that the low rigidity subflooring material makes the uneven surface consolidated Japanese cedar floor finish material more difficult to walk on.