Effects of seasoning on the vibrational properties of wood for the soundboards of string instruments

Obataya, Eiichi; Zeniya, Nanami; Endo-Ujiie, Kaoru

doi:10.1121/10.0000723

Cited by 12 publications

(13 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However microstresses are likely at the molecular scale, i.e. within the conformation of cell-wall polymers (Hunt 1997, Obataya et al 2020. In present results, for RH trajectories that involved a single protocol/sampling, the drying and the humidifying paths showed very similar trends, with very little hysteresis in destabilisation.…”

Section: Destabilisation Expressed By Non-linear Evolution Of Damping Against Moisture Contentsupporting

confidence: 54%

“…From a fundamental point of view of wood physics, little is known about the slow reach to equilibrium after destabilisation, i.e. about physical ageing, in the domain of dynamic, vibrational properties, exception made from evidence in the few previously cited articles (Gril 1988;Hunt 1997;Hunt and Balsan 1996;Hunt and Gril 1996;Obataya et al 2020;Suzuki 1962;Sasaki et al 1988).…”

Section: Estimating the Approach Tomentioning

confidence: 99%

“…Following a destabilisation, the approach towards new equilibrium, i.e. physical ageing, is found to be very slow (Ishimaru et al 2001) or even, in green wood, seemingly "never ending" (Dlouha et al 2009;Obataya et al 2020). Hunt and Gril (1996) put forward the hypothesis that destabilisation followed by physical ageing can explain various observed anomalies in wood behaviour.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Transient destabilisation in anisotropic vibrational properties of wood when changing humidity

Brémaud

Gril

2020

Holzforschung

View full text Add to dashboard Cite

Moisture changes cause transient effects in various polymeric materials. In wood, they are mainly documented in semi-static or low-frequency domains and could explain various anomalies in wood behaviour, including the so-called mechano-sorptive effect. This article aimed at exploring and quantifying transient effects in wood vibrational properties, evidenced but in few publications. A series of 65 experiments on spruce and maple, in longitudinal (L) and radial (R) directions, spanning many humidity trajectories, were monitored through time (1–7 weeks) after step-change in relative humidity (RH). Changes in dimensions and specific dynamic modulus of elasticity (E′/γ) closely followed change in moisture content (MC). But the damping coefficient (tanδ) always increased (whether MC increased or decreased) within first hours/days, before slowly re-decreasing. This was quantitatively analysed by subtracting equilibrium moisture content (EMC) dependence from the global changes in tanδ, which simultaneously expressed destabilisation, followed by physical ageing (a slow process towards approaching equilibrium). For small EMC steps, the amplitude of destabilisation in L tanδ exceeded changes due to EMC dependence. Destabilisation was of similar importance relative to L or to R tanδ, while R tanδ showed much (2−4×) stronger EMC dependence. Amplitude of destabilisation increased with wider RH/EMC-steps (and faster sorption rates). Within an experiment, maximum destabilisation occurred nearly concomitantly with maximum sorption rate. Equilibrium was usually reached in MC, even within one week, but seldom in tanδ, even after several weeks. Results suggested that: (i) drying caused similar amplitudes of destabilisation, but that occurred sooner, and recovered faster, than humidifying; (ii) small RH-steps caused relatively smaller amplitudes of destabilisation, but that occurred later, and spanned over longer time before recovering equilibrium, than wide RH-steps. Some possible hypotheses are introduced to explain the observed phenomena. These phenomena also have important practical consequences in real-life wood uses and, particularly, in the design of experimental protocols.

show abstract

Section: Destabilisation Expressed By Non-linear Evolution Of Damping Against Moisture Contentsupporting

confidence: 54%

Section: Estimating the Approach Tomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Transient destabilisation in anisotropic vibrational properties of wood when changing humidity

Brémaud

Gril

2020

Holzforschung

View full text Add to dashboard Cite

show abstract

“…Tests were done by non-contact forced-released vibrations of free-free slender beams, a most widely used method for wood vibrational properties (Fukada 1950;Obataya et al 2000bObataya et al , 2020. On this principle, measurements used a custom-built hardware and software device that reduces testing time and error (Brémaud 2006;Brémaud et al 2012).…”

Section: Vibrational Measurementsmentioning

confidence: 99%

“…However, in ADS and DES trajectories, the effect of history could not be ruled out. Destabilisation due to drying, but also to water re-saturation, are observed in DMTA -Dynamic Mechanical Thermal Analysis (Furuta et al 1995, Kojiro et al 2008, and complex reversible/ irreversible effects of ageing, seasoning, heating and moistening on EMC and vibrational properties are acknowledged (Obataya et al 2000a, Obataya and Tomita 2002, Obataya 2017, Obataya et al 2020. Water immersion could also remove extractives and reduce damping, as found in reed and bamboo (Obataya andNorimoto 1995, Inokuchi et al 1999), maybe also in maple (Roohnia et al 2015), but not in spruce (Sonderegger et al 2008).…”

Section: Is There a Hysteresis In Vibrationalmentioning

confidence: 99%

Moisture content dependence of anisotropic vibrational properties of wood at quasi equilibrium: analytical review and multi-trajectories experiments

Brémaud

Gril

2020

Holzforschung

View full text Add to dashboard Cite

This article aims at providing a synthetic view of the equilibrium moisture content (EMC) dependence of wood vibrational properties (i.e. dynamic mechanical properties in the audio-frequency range), including specific dynamic modulus of elasticity (E′/γ) and damping coefficient expressing internal friction (tanδ). A series of multi-trajectories experiments was designed to complete an analytical review. Literature indicates that: (1) in longitudinal (L) direction, the EMC dependence of E′/γ shows a very consistent shape (rather linear) between studies, while its shape is non-linear for tanδ and varies significantly between studies; (2) EMC dependence of tanδ is rather well documented in the L direction, in adsorption, for softwoods, but data covering EMC dependence in both L and other anisotropic directions, and sorption hysteresis, are still scarce. Experiments were conducted on a softwood (spruce) and a hardwood (maple), in L and radial (R) directions, in full adsorption from oven-dry state, full desorption from water-saturated state, and relative humidity (RH) loops without extreme conditioning. Measurements were made at conditions considered “at equilibrium” and some were monitored through time. Results indicated that tanδ was much more (×3) sensitive to EMC differences than E′/γ. R properties, especially tanδR, were much more (×2–3) sensitive than L properties – resulting in strong increase of anisotropy with increasing EMC. In L direction, differences due to EMC remained moderate compared to the natural variability of wood for E′/γ, while for tanδ the EMC-induced changes were at least equal to natural variability in high-grade spruce. Vibrational properties did exhibit a hysteresis as a function of RH, but very little hysteresis as a function of EMC. The tanδ-EMC relation strongly depended on the actual time of stabilisation after reaching EMC. A related paper will address the transient, out of equilibrium effects of changing moisture conditions on the vibrational properties of wood.

show abstract

Variation of the acoustic response of Karadeniz kemenche due to the size and geometry of the sound holes

Alkın,

Oktav

2024

Applied Acoustics

View full text Add to dashboard Cite

Effects of seasoning on the vibrational properties of wood for the soundboards of string instruments

Abstract: Title: Effects of seasoning on the vibrational properties of wood for the soundboards of string instruments.

Cited by 12 publications

References 16 publications

Transient destabilisation in anisotropic vibrational properties of wood when changing humidity

Transient destabilisation in anisotropic vibrational properties of wood when changing humidity

Moisture content dependence of anisotropic vibrational properties of wood at quasi equilibrium: analytical review and multi-trajectories experiments

Variation of the acoustic response of Karadeniz kemenche due to the size and geometry of the sound holes

Contact Info

Product

Resources

About