Banner for LabNotes
From Lab Notes
Contact Information
Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592
Email

 

You are here: FPL Home  / Information Products & Services  / Publications

Requested Product

Title: Modeling temperature and moisture state effects on acoustic velocity in wood

Source: In: Proceedings, 17th International Nondestructive Testing and Evaluation of Wood Symposium, Sopron, Hungary, 14-16 September. p. 411-418.

Author(s)Gao, Shan; Wang, X.; Wang, L.; Bruce, R.B.

Publication Year: 2011  View PDF »

Category: Conference Proceedings
Associated Research Project(s):   FPL-4714-1A

Abstract: Previous research has proved the concept of acoustic wave propagation methods for evaluating wood quality of trees and logs during forest operations. As commercial acoustic equipment is implemented in field for various purposes, one has to consider the influence of operating temperature on acoustic velocity — a key parameter for wood property prediction. Our field study on acoustic monitoring of standing trees and logs over one-year cycle showed a significant change in acoustic velocity as seasonal temperature changed. The purpose of this study is to further investigate the effects of temperature and moisture state of wood on acoustic properties in a laboratory-controlled environment. Small clear specimens (25.4 x25.4 x407 mm) obtained from a freshly-cut red pine (Pinus resinosa) log were conditioned to four moisture content (MC) levels: green (fresh-cut condition), 24% MC, 12% MC and 0% MC. All specimens were acoustically tested using an ultrasonic device over a temperature range of -45 °C and 35 °C. The results indicated that wood temperature had a significant effect on acoustic velocity in frozen wood. Below the freezing point, acoustic velocity increased as wood temperature decreased. When wood temperature was well above freezing, velocity in green wood was not significantly affected by temperature change. It was found that wood moisture content had a significant compounding effect on the velocity-temperature relationships. Temperature effect was much more significant in green wood than in dry wood. In green wood, both velocity and energy loss changed abruptly around the freezing point (-2.5°C~ 2.5°C) due to the phase transformation of free water in the cell lumens.

Keywords: Acoustic velocity; energy loss; logs; moisture content; temperature; trees

Publication Review Process: Informally Refereed (Peer-Reviewed)

File size: 320 kb(s)

Date posted: 10/25/2012

This publication is also viewable on Treesearch:  view
RITS Product ID: 62675
Current FPL Scientist associated with this product
Wang, Xiping
Research Forest Products Technologist
  

Additional items that might interest you
View the video celebrating FPL's 100 years of public service in 2010, from the producers of the Greatest Good....view

Research Highlights from FPL....view

Termite Eradication: A search for the Holy Grail.... view

Moisture Management in Residential Construction Series videos...view

Wood Floor Systems in Residential Construction Series videos....view
- FPL's Mission and Strategic Plan -

FPL's mission is to identify and conduct innovative wood and fiber utilization research that contributes to conservation and productivity of the forest resource, thereby sustaining forests, the economy, and quality of life. ... ..more »

- FPL Research Emphasis Areas -
Advanced Composites

As an integral part of the FPL mission, we improve the long-term sustainability of our Nation's forests by creating valuable composite products from biobased materials ... ..more »


Advanced Structures

The FPL has been in the forefront of wood-frame housing research since 1910 and has long been recognized as a world leader in such housing-related areas as engineered wood ... ..more »


Forest Biorefinery

We all know the compelling reasons that the United States needs to reduce its dependence on fossil fuels. Historically, the greatest increases in energy demand have been for transportation fuels ... ..more »


Nanotechnology

A leader in wood products research for over a century, the FPL is positioning itself to become the lead Federal research facility for the application of nanotechnology in forest products ... more »


Woody Biomass Utilization

Forests in the United States contain a substantial amount of small-diameter, overstocked, and underutilized material.FPL research projects are exploring the potential of the small-diameter ... ..more »