Effect of moisture content on ultrasonic velocity and attenuation in woods

Sakai, Hiroya; Minamisawa, Akiko; Takagi, Kenshiro

doi:10.1016/0041-624x(90)90060-2

Cited by 70 publications

(39 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Sound velocity decreases dramatically with moisture content up to the FSP (Sakai et al 1990), which could be confirmed by our investigations (Table 7). Sakai et al (1990) found the decrease to run linearly up to the FSP.…”

Section: Influence Of Moisture Content On Sound Velocitiessupporting

confidence: 76%

Determination of Young’s and shear moduli of common yew and Norway spruce by means of ultrasonic waves

et al. 2006

View full text Add to dashboard Cite

Despite the exceptional position of yew among the gymnosperms concerning its elastomechanical properties, no reference values for its elastic constants apart from the longitudinal Young's modulus have been available from literature so far. Hence, this study's objective was to determine the Young's moduli E L , E R and E T and the shear moduli G LR , G LT and G RT of yew wood. For that purpose, we measured the ultrasound velocities of longitudinal and transversal waves applied to small cubic specimens and derived the elastic constants from the results. The tests were carried out at varying wood moisture contents and were applied to spruce specimens as well in order to put the results into perspective. Results indicate that E L is in the same order of magnitude for both species, which means that a high-density wood species like yew does not inevitably have to have a high longitudinal Young's modulus. For the transverse Young's moduli of yew, however, we obtained 1.5-2 times, for the shear moduli even 3-6 times higher values compared to spruce. The variation of moisture content primarily revealed differences between both species concerning the shear modulus of the RT plane. We concluded that anatomical features such as the microfibril angle, the high ray percentage

show abstract

Section: Influence Of Moisture Content On Sound Velocitiessupporting

confidence: 76%

Determination of Young’s and shear moduli of common yew and Norway spruce by means of ultrasonic waves

et al. 2006

View full text Add to dashboard Cite

show abstract

“…The acoustic velocity in wood also varies with moisture content (MC), which may change with the season of the year. 47,[80][81][82][83][84][85][86][87][88][89][90] The longitudinal velocity has been reported to reduce with increased MC, while the radial and tangential velocities may vary (decrease and increase) as MC was varies. 83 In addition, the density of wood increases with MC.…”

Section: Orthotropic Mechanical Properties Of Woodmentioning

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

View full text Add to dashboard Cite

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.

show abstract

“…According to 140 kHz results of Vun et al (2008), at Ts238C a MC change from 27 to 151% introduces ACU NTM transmission variations of 6 dB in 25 mm thick solid wood. Sakai et al (1990) measured at 1 MHz for several wood species transmission variations below 2 dB and sound speed variations of 10% for a MC interval between 0% and 20%. Sandoz (1993) observed at 50 kHz similar sound speed variations in structural wood grading.…”

Section: Defect Monitoring With Difference Imagingmentioning

confidence: 99%

Air-coupled ultrasound inspection of glued laminated timber

et al. 2011

View full text Add to dashboard Cite

A novel air-coupled ultrasound (ACU) 120 kHz normal transmission system enabled successful imaging of bonding and saw cut defects in multilayered glulam beams up to 280 mm in height with a signal-to-noise ratio (SNR) of 40 dB. The main wave propagation paths were modeled; quasi-longitudinal and quasi-transverse modes were coupled in each lamella and the sound field was found to be shifted from the insonification axis as a function of the ring angle, leading to interference of wave paths in the receiver and to 15 dB amplitude variability in defect-free glulam. The assessment was improved with spatial processing algorithms that profited from the arbitrary scanning resolution and high reproducibility of ACU. Overlapped averaging reduced inband noise by 15 dB, amplitude tracking captured only the first incoming oscillation, thus minimizing diffraction around defect regions, and image normalization compensated 6 dB of systematic amplitude variability across the fiber direction. The application of ACU to in situ defect monitoring was demonstrated by using multiparameter difference imaging of measurements of the same sample with and without saw cut defects. The segmentation of the defect geometry was improved significantly and the amplitude variability was reduced by 10 dB. Further work is planned to model additional insonification setups and grain and density heterogeneities.

show abstract

Effect of moisture content on ultrasonic velocity and attenuation in woods

Cited by 70 publications

References 1 publication

Determination of Young’s and shear moduli of common yew and Norway spruce by means of ultrasonic waves

Determination of Young’s and shear moduli of common yew and Norway spruce by means of ultrasonic waves

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

Air-coupled ultrasound inspection of glued laminated timber

Contact Info

Product

Resources

About