Acoustic wave propagation in standing trees-part I. Numerical simulation

Fenglu Liu, Xiping Wang, Houjiang Zhang, Fang Jiang, Wenhua Yu, Shanqing Liang, Feng Fu, Robert J. Ross

Research output: Contribution to journalArticle

Abstract

The use of acoustic waves for assessing wood properties in standing trees has been investigated extensively in recent years. Most studies were experimental in nature and limited to direct measurement of wave velocities in trees using a time-of-flight (TOF) method. How acoustic waves propagate in a tree trunk and how tree diameter, species, stand age, and juvenile wood affect wave propagation behavior in standing trees are not well understood. In this study, we examined propagation patterns of acoustic waves in a virtual tree trunk through numerical simulation using COMSOL Multiphysics® software (COMSOL, Inc., Burlington, MA). The simulationwas based on the elastic theory of a solidmediumwith the assumption of an orthotropicmaterial for a standing tree. Extensive acousticmeasurements were conducted on green larch log samples to validate the simulation results. Our results showed that the wave front maps of the tree model from numerical simulations were consistent with those obtained through TOF measurements on the log samples, indicating that the simulation results were accurate and reliable.Wave propagation patterns of the treemodel revealed that the side surface-generated acoustic wave expanded as a dilatational wave within a 0- to 1.2-m transit distance; as the wave moved up along the tree model, the shape of the wave front gradually flattened and the wave eventually transformed into a quasi-plane wave from a 2.4-m transit distance.

Original languageEnglish (US)
Pages (from-to)53-72
Number of pages20
JournalWood and Fiber Science
Volume52
Issue number1
DOIs
StatePublished - Jan 1 2020
Externally publishedYes

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Keywords

  • Acoustic waves
  • Boundary condition
  • COMSOL Multiphysics software
  • Impulse load
  • Orthotropic material
  • Trees
  • Wave front

Cite this

Liu, F., Wang, X., Zhang, H., Jiang, F., Yu, W., Liang, S., Fu, F., & Ross, R. J. (2020). Acoustic wave propagation in standing trees-part I. Numerical simulation. Wood and Fiber Science, 52(1), 53-72. https://doi.org/10.22382/wfs-2020-006