Download (PDF 414 KB): https://research.fs.usda.gov/download/treesearch/39500.pdf
Abstract
Nondestructive evaluation (NDE) of wood quality in standing trees is an important procedure in the forest operational value chain worldwide. The goal of this paper is to investigate how a stress wave travel in a tree stem as it is introduced into the tree through a mechanical impact. Experimental stress wave data was obtained on freshly cut red pine logs in the laboratory. Three dimensional (3D) stress wave contour maps were generated using the MATLAB software. The 3D stress wave contour maps represent the wave fronts at a series of locations along the length, which can help to visualize the propagation of stress waves in a tree stem. The experimental simulation of wave fronts in the log specimens shows that stress waves travel as a three dimensional wave initially, then gradually transformed to a quasi one dimensional wave with a non-flat wave front.
Keywords
Wood deterioration,
testing,
red pine,
pine grading,
mechanical properties,
wood grading,
pine,
acoustic properties,
wood quality,
grading,
wood defects,
stress waves,
nondestructive testing,
acoustic imaging,
Pinus resinosa,
pine decay,
standing trees,
acoustic testing,
wood decay,
log quality,
log grading,
3D stress wave contour maps,
trees
Citation
Su, Juan; Zhang, Houjiang; Wang, Xiping. 2009. Stress wave propagation on standing trees. Part 2, Formation of 3D stress wave contour maps. In: Proceedings of the 16th International Symposium on Nondestructive Testing and Evaluation of Wood, October 12-14, 2009, Beijing, China. Beijing, China : Beijing Forestry University, c2009: p. 59-64.
