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Title: Experimental investigation of stress wave propagation in standing trees

Source: Holzforschung, Volume 65, pp. 743-748, 2011

Author(s)Zhang, Houjiang; Wang, Xiping; Su, Juan

Publication Year: 2011  View PDF »

Category: Journal Articles
Associated Research Project(s):   FPL-4714-1A

Abstract: The objective of this study was to investigate how a stress wave travels in a standing tree as it is introduced into the tree trunk through a mechanical impact. A series of stress wave time-of-flight (TOF) data were obtained from three freshly-cut red pine (Pinus resinosa Ait.) logs by means of a two-probe stress wave timer. Two-dimensional (2D) and three-dimensional (3D) stress wave contour maps were constructed based on the experimental data using a commercial software. These stress wave contour maps represent the wave fronts in a time sequence, illustrating the flow of stress wave energy within a log. The analysis of TOF data and wave fronts indicates that stress wave propagation in standing trees is affected by tree diameter, travel distance, and internal wood conditions (wood properties and structural defects). When a stress wave is introduced into a tree trunk from a point source, it initially propagates in the impact direction as a 3D wave. Then the flow of the stress wave energy gradually changes towards the longitudinal directions. As the diameter-to-distance ration reaches 0.1 or below, the wave begins to travel as a quasi 1D wave.

Keywords: Wood deterioration; red pine; pine; grading; mechanical properties; wood grading; acoustic properties; wood quality; wood defects; stress waves; nondestructive testing; acoustic imaging; Pinus resinosa; wood testing; testing methods; pine decay; standing trees; acoustic testing; wood decay; log quality; log grading; 2D stress wave contour maps; 3D stress wave contour maps; knots; logs; stress wave contour map; stress wave propagation; time-of-flight; wave front

Publication Review Process: Formally Refereed

File size: 505 kb(s)

Date posted: 09/07/2011

This publication is also viewable on Treesearch:  view
RITS Product ID: 39436
Current FPL Scientist associated with this product
Wang, Xiping
Research Forest Products Technologist

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