Experimental and numerical investigation of effect of sawn timber dimensions in ultrasonic velocity measurements of Spanish softwoods

Fernández Llana, Daniel and Iñiguez Gonzalez, Guillermo and Arriaga Martitegui, Francisco and Sanabria Martin, Sergio Jose and Niemz, Peter (2013). Experimental and numerical investigation of effect of sawn timber dimensions in ultrasonic velocity measurements of Spanish softwoods. In: "Proceedings 18th International Nondestructive Testing and Evaluation of Wood Symposium. Madison, Wisconsin, USA 2013", 24/09/2013 - 27/09/2013, Madison, Wisconsin, Estados Unidos de América. p. 710.

Description

Title: Experimental and numerical investigation of effect of sawn timber dimensions in ultrasonic velocity measurements of Spanish softwoods
Author/s:
  • Fernández Llana, Daniel
  • Iñiguez Gonzalez, Guillermo
  • Arriaga Martitegui, Francisco
  • Sanabria Martin, Sergio Jose
  • Niemz, Peter
Item Type: Presentation at Congress or Conference (Poster)
Event Title: Proceedings 18th International Nondestructive Testing and Evaluation of Wood Symposium. Madison, Wisconsin, USA 2013
Event Dates: 24/09/2013 - 27/09/2013
Event Location: Madison, Wisconsin, Estados Unidos de América
Title of Book: Proceedings 18th International Nondestructive Testing and Evaluation of Wood Symposium
Date: 2013
Subjects:
Faculty: E.T.S.I. Montes (UPM)
Department: Construcción y Vías Rurales [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Ultrasonic sound velocity measurements with hand-held equipment remain due to their simplicity among the most used methods for non-destructive grading of sawn woods, yet a dedicated normalization effort with respect to strength classes for Spanish species is still required. As part of an ongoing project with the aim of definition of standard testing methods, the effect of the dimensions of commonly tested Scots pine (Pinus sylvestris L.) timbers and equipment testing frequency on ultrasonic velocity were investigated. A dedicated full-wave finite-difference time-domain software allowed simulation of pulse propagation through timbers of representative length and section combinations. Sound velocity measurements vL were performed along the grain with the indirect method at 22 kHz and 45 kHz for grids of measurement points at specific distances. For sample sections larger than the cross-sectional wavelength ?RT, the simulated sound velocity vL converges to vL = (CL/?)0.5. For smaller square sections the sound velocity drops down to vL = (EL/?)0.5, where CL, EL and ? are the stiffness, E-modul and density, respectively. The experiments confirm a linear regression between time of flight and measurement distance even at less than two wavelength menor que2?L distance, the fitted sound speed values increased by 15% between the two tested frequencies.

More information

Item ID: 22941
DC Identifier: http://oa.upm.es/22941/
OAI Identifier: oai:oa.upm.es:22941
Deposited by: Memoria Investigacion
Deposited on: 25 Mar 2014 11:15
Last Modified: 21 Apr 2016 20:55
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