Relationships between anatomical and vibrational properties of wavy sycamore maple

Alkadri, Ahmad; Carlier, Capucine; Wahyudi, Imam; Gril, Joseph; Langbour, Patrick; Brémaud, Iris

doi:10.1163/22941932-20170185

Cited by 13 publications

(7 citation statements)

References 30 publications

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“…markedly lower (−35%) ratio of elastic anisotropy. The studied maple being straight-grained (not wavy), this smaller anisotropy might be due to a combined effect of wider microfibril angle, and of stronger reinforcement by rays (Alkadri et al 2018). The two species were less distinct in damping, than in moduli.…”

Section: Emc Dependence Of Anisotropic Vibrational Properties In Full Ad-or Desorption: Softwood Versus Hardwoodmentioning

confidence: 93%

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

Brémaud

Gril

2020

Holzforschung

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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.

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Section: Emc Dependence Of Anisotropic Vibrational Properties In Full Ad-or Desorption: Softwood Versus Hardwoodmentioning

confidence: 93%

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

Brémaud

Gril

2020

Holzforschung

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“…Special patterns like flames for maple or indented rings for spruce are selected for aesthetic as well as mechanical considerations. Indeed, a recent study pointed out that flames in maple changed the mechanical properties of the wood [7]. Moreover, the indented rings of spruce, also known as bear claw, reduce anisotropy in the wood [8].…”

Section: Scopementioning

confidence: 99%

Simultaneous non-destructive identification of multiple elastic and damping properties of spruce tonewood to improve grading

Viala

Placet

Cogan

2020

Journal of Cultural Heritage

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The tonewoods used in musical instruments are finely selected and are subject to current and upcoming availability issues. Wood grading assesses the quality of the tonewood and depends on both subjective and objective criteria. Traditionally, grading criteria based on mechanical properties consider mainly the longitudinal direction. This paper investigates the elastic and damping properties of spruce wood used in the making of acoustical guitars and violins. In this context, the mechanical grading properties will be studied in multiple directions. A non-destructive vibrational characterization method is used to simultaneously identify at least six mechanical properties of wood and leads to the determination of the elastic and damping parameters of wood along the different material directions. The main objective is to quantify the variability of the mechanical properties in different material directions as a function of the grading attributed by the wood seller. The results show that material anisotropy decreases as the grade decreases. This is attributed to strong increase of the specific elastic modulus in the radial direction and the specific shear modulus in longitudinal and radial plane. Moreover, grading seems to be assigned as a function of specific elasticity and loss factor in the longitudinal direction, which is tied in with the preferences of instrument makers. Following the assumption that high specific modulus is desirable, the classification based on instrument makers choices can be improved for new grading criteria that consider directions than longitudinal. Moreover, the substitution of wood species and the proposal of new materials exhibiting equivalent elastic and damping properties can be proposed. Highlights • Simultaneous non-destructive determination of at least six elastic and damping properties of tonewood. • Description of elastic and damping properties as a function of tonewood grades. • Decrease of specific longitudinal modulus and increase of longitudinal loss factor for decreasing grades. • Increase of specific elastic modulus in radial direction and specific shear modulus in longitudinal and radial plane for decreasing grades.

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“…The microfibrils’ angle in S2 and the deflection of the fibers show significant correlations with the vibrational properties in the longitudinal direction but not perpendicular to the wood grains. The collective effect of the microfibril angle and grain angle on both E sp and ϑ is higher than their individual effects on these properties [ 59 , 60 , 61 ].…”

Section: Resultsmentioning

confidence: 99%

Thermal Modification of Spruce and Maple Wood for Special Wood Products

et al. 2022

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This article presents a proposal of thermal modification of Norway spruce and sycamore maple for special wood products, mainly for musical instruments. Selected physical and acoustical characteristics (PACHs), including the density (ρ), dynamic modulus of elasticity along the wood grain (EL), specific modulus (Esp), speed of sound along the wood grain (cL), resonant frequency (fr) and acoustic constant (A), logarithmic decrement (ϑ), loss coefficient (η), acoustic conversion efficiency (ACE), sound quality factor (Q), and the timbre of sound, were evaluated. These two wood species were chosen regarding their use in the production or repair of musical instruments. For the thermal modification, a similar process to the ThermoWood process was chosen. Thermal modification was performed at the temperatures 135 °C, 160 °C and 185 °C. The resonant dynamic method was used to obtain the PACHs. Fast Fourier transform (FFT) was used to analyze the sound produced. The changes in the observed wood properties depended on the treatment temperature. Based on our results of all properties, the different temperature modified wood could find uses in the making of musical instruments or where the specific values of these wood characteristics are required. The mild thermal modification resulted in a decrease in mass, density, and increased speed of sound and dynamic modulus of elasticity at all temperatures of modification. The thermally modified wood showed higher sound radiation and lower loss coefficients than unmodified wood. The modification also influenced the timbre of sound of both wood species.

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Relationships between anatomical and vibrational properties of wavy sycamore maple

Cited by 13 publications

References 30 publications

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

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

Simultaneous non-destructive identification of multiple elastic and damping properties of spruce tonewood to improve grading

Thermal Modification of Spruce and Maple Wood for Special Wood Products

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