Wood hardness of utility poles. Part 2. Transposition of a wood hardness indicator into a measuring instrument in correlation with Linemen's perception

Citation
R. Gilbert et al., Wood hardness of utility poles. Part 2. Transposition of a wood hardness indicator into a measuring instrument in correlation with Linemen's perception, FOREST PROD, 48(11-12), 1998, pp. 91-97
Citations number
8
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences
Journal title
FOREST PRODUCTS JOURNAL
ISSN journal
0015-7473 → ACNP
Volume
48
Issue
11-12
Year of publication
1998
Pages
91 - 97
Database
ISI
SICI code
0015-7473(199811/12)48:11-12<91:WHOUPP>2.0.ZU;2-C
Abstract
In Part 1 of this project, the possibility of correlating the linemen's per ception of the hardness of a series of poles by using measurements of penet ration and impact on the gaff was demonstrated. In Part 2, the performance of two portable instruments used to correlate the hardness perceived by the linemen is evaluated. The Psychophysical Wood Hardness Perception Tester a nd the Wood Pole Hardness Tester use a mechanized gaff to measure wood hard ness. The measurements were made in comparison with the Pilodyn 6J, which c onsists of projecting a metal rod into the wood. These instruments were tes ted in three series of tests during which linemen used their psychophysical perception of hardness to rate a series of poles by degree of hardness. Th e two instruments equipped with a gaff were modified during testing to more closely match human perception The results show that it is possible to app roximate the linemen's assessment using the Psychophysical Wood Hardness Pe rception Tester, which measures both penetration and impact. The measuremen ts are not affected by the species/treatment combinations as is the case wi th the Pilodyn readings. The latest version of the instrument consists of a pneumatic jack attached to a bracket through a rotating joint and equipped with an internal displacement sensor, a piezoelectric load cell, an accele rometer, and a gaff welded in its axis at the upper edge. The angle of appl ication of the force is 20 degrees, with an angle of 30 degrees between the upper edge of the gaff and the surface of the pole. Finally, it was demons trated that the hardness indicator concept developed during Part 1 of this study can be transposed into a measuring instrument.