The Viscoelastic Properties of Wood Used for the Musical Instruments I

Abstract

This study deals with the viscoelastic properties of wood used for the musical instruments and various other species. The properties were measured by composite oscillator at 60 kHz, vibrating reed at 55～65 Hz, and stress relaxation over the time range of 10 to 1000 sec. The results are summarized as follows: (1) There observed the two major frequency dispersions for wood in radial and tangential directions. The dispersion in very low frequency range is probably due to the movement of rather large segments of the structures, while that of high frequency range may be asociated with the motion of methylol groups in the non-crystalline region of wood substance. (2) The values of the dynamic loss modulus of hardwood in tangential direction increased linearly with increasing p in linear scale up to ρ=1.3. On the other hand, the values in radial direction increased linearly with ρ up to ρ=0.7 and then remained almost constant aboveρ=0.7. (3) The values of the dynamic loss modulus did not change by the extraction. (4) The values of the dynamic elastic modulus and loss modulus for wood used for the musical instruments (Sitka spruce and Yezo spruce) were larger than those of other species in the longitudinal direction.