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 language | English (US) |
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Pages (from-to) | 53-72 |
Number of pages | 20 |
Journal | Wood and Fiber Science |
Volume | 52 |
Issue number | 1 |
DOIs | |
State | Published - 2020 |
Externally published | Yes |
Bibliographical note
Funding Information:This project was conducted through the research cooperation between Beijing Forestry University and the USDA Forest Service Forest Products Laboratory (11-MU-11111133-031; 18-LI-11111133-024) and was partially funded by the National Natural Science Foundation of China (grant no. 31328005). Financial support to Mr. Fenglu Liu’s visiting study in the United States was provided by the China Scholarship Council.
Funding Information:
This project was conducted through the research cooperation between Beijing Forestry University and theUSDA Forest Service Forest Products Laboratory (11-MU-11111133-031; 18-LI-11111133-024) and was partially funded by the National Natural Science Foundation of China (grant no. 31328005). Financial support to Mr. Fenglu Liu's visiting study in the United States was provided by the China Scholarship Council.
Publisher Copyright:
© 2020 by the Society of Wood Science and Technology.
Keywords
- Acoustic waves
- Boundary condition
- COMSOL Multiphysics software
- Impulse load
- Orthotropic material
- Trees
- Wave front