Differences in acoustic velocity by resonance and transit-time methods in an anisotropic laminated wood medium

Chauhan, Shakti; Entwistle, K. M.; Walker, J. C. F.

doi:10.1515/hf.2005.070

Cited by 26 publications

(16 citation statements)

References 2 publications

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“…It is well known that speed of stress wave pulse depends on the Young's modulus and density of the material. Chauhan et al (2005) have shown that acoustic velocity by longitudinal vibration is the function of the volume weighted average stiffness of the entire sample under the test. Therefore, DMoE from resonance frequencies (longitudinal or flexural vibrations) remain unbiased from the localized variations within the sample and are more close to the static MoE.…”

Section: Resultsmentioning

confidence: 99%

“…Divos and Tanaka (2005) reported the effect of frequency of measurement on determination of modulus of elasticity and found higher MoE with increasing frequencies. Chauhan et al (2005) reported 4% to 26% difference in acoustic velocity measured by resonance and transit time tool in laminated wood panels with different magnitude of in-homogeneity which in turn represent 8% to 52% difference in their DMoE. The difference was attributed to the mechanism of wave propagation in anisotropic wood medium.…”

Section: Introductionmentioning

confidence: 96%

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Differences in dynamic modulus of elasticity determined by three vibration methods and their relationship with static modulus of elasticity

Chauhan

Sethy

2016

Maderas, Cienc. tecnol.

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Dynamic modulus of elasticity was determined in clearwood samples of eight tropical hardwood species using longitudinal vibrations, flexural vibration and ultrasonic transit-time methods. These samples were subsequently subjected to three point static bending test to determine static modulus of elasticity and modulus of rupture. Acoustic velocity and wood density were found to be independent parameters as the velocity was nearly the same in wood with distinctly different densities. Among the three dynamic measurements, modulus from the ultrasonic method was the highest followed by the longitudinal vibration and flexural vibration. Any of three vibration methods could be used to predict static modulus as they exhibited a near perfect correlation with static MoE. However, the dynamic modulus determined by different vibration methods were found to diverge with increasing static modulus. Wood density was the dominating factor influencing both modulus of elasticity and modulus of rupture.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Differences in dynamic modulus of elasticity determined by three vibration methods and their relationship with static modulus of elasticity

Chauhan

Sethy

2016

Maderas, Cienc. tecnol.

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“…The dynamic modulus of elasticity (MOEd - Urhan et al 2014) can be estimated from the velocity of acoustic waves (acoustic velocity, CT) passing through the wood, according to the following formula (eqn. 2): (2) where WD is the wood density, expressed in kg m -3 , and AV is the velocity in km s -1 (Pellerin & Ross 2002, Chauhan et al 2005, Lasserre et al 2007). Wood density was determined by volumetric methods, which required measuring the volume and mass of dry wood in the laboratory.…”

Section: The Modulus Of Elasticity Equationmentioning

confidence: 99%

Acoustic evaluation of wood quality with a non-destructive method in standing trees: a first survey in Italy

Proto¹,

Macrì²,

Bernardini³

et al. 2017

iForest

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Research and development efforts are currently underway worldwide to examine the potential use of a wide range of non-destructive technologies (NDT) for evaluating wood and wood-based materials, from the assessment of standing trees to in-place structures. For this purpose, acoustic velocity by the Fakopp time of flight (TOF) tool was used to estimate the influence of four thinning treatments performed in Southern Italy. The objective of the study was to determine if the effects of silvicultural practices on wood quality can be identified using acoustic measurement to assess the MOEd of standing trees with non-destructive method in Calabrian pine (Pinus nigra Arnold subsp. calabrica). Four hundred and fifty standing trees from four sites were nondestructively tested using a time-of-flight acoustic wave technique. The thinning trials were conducted on 60-year-old plantations of Calabrian pine in four plots under different treatments: Control (T), light thinning (A), intermediate thinning (B) and heavy thinning (C). Statistical analysis demonstrated significant stress wave time differences between the stands with moderate thinning (A and B) and those with heavy thinning (C). The results showed that tree diameter has significant influence on acoustic wave measurements and a valid relationship exists between diameter at breast height and tree velocity. The results of these studies proved that the stress wave technique can be successfully applied on standing trees.

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“…It has been suggested this technique provides MOE measurements, which are an average through the cross-section of the log. 124,159,174 This has been associated with the fact that it uses an acoustic signal that has propagated many times through the length of the log due to multiple reflections from each end. However, there are a few factors that have been suggested as potential sources of errors in resonance measurements.…”

Section: Fakoppmentioning

confidence: 99%

Measurement of stiffness of standing trees and felled logs using acoustics: A review

Legg

Bradley

2016

The Journal of the Acoustical Society of America

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This paper provides a review on the use of acoustics to measure stiffness of standing trees, stems, and logs. An outline is given of the properties of wood and how these are related to stiffness and acoustic velocity throughout the tree. Factors are described that influence the speed of sound in wood, including the different types of acoustic waves which propagate in tree stems and lumber. Acoustic tools and techniques that have been used to measure the stiffness of wood are reviewed. The reasons for a systematic difference between direct and acoustic measurements of stiffness for standing trees, and methods for correction, are discussed. Other techniques, which have been used in addition to acoustics to try to improve stiffness measurements, are also briefly described. Also reviewed are studies which have used acoustic tools to investigate factors that influence the stiffness of trees. These factors include different silvicultural practices, geographic and environmental conditions, and genetics.

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Differences in acoustic velocity by resonance and transit-time methods in an anisotropic laminated wood medium

Cited by 26 publications

References 2 publications

Differences in dynamic modulus of elasticity determined by three vibration methods and their relationship with static modulus of elasticity

Differences in dynamic modulus of elasticity determined by three vibration methods and their relationship with static modulus of elasticity

Acoustic evaluation of wood quality with a non-destructive method in standing trees: a first survey in Italy

Measurement of stiffness of standing trees and felled logs using acoustics: A review

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