Observatorio de I+D+i UPM

Memorias de investigación
Communications at congresses:
Experimental and numerical investigation of effect of sawn timber dimensions in ultrasonic velocity measurements of Spanish softwoods
Year:2013
Research Areas
  • Civil engineering,
  • Construction of buildings,
  • Rehabilitation of buildins
Information
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 <2?L distance, the fitted sound speed values increased by 15% between the two tested frequencies.
International
Si
Congress
18th International Nondestructive Testing and Evaluation of Wood Symposium
960
Place
Madison, Wisconsin, Estados Unidos de América
Reviewers
Si
ISBN/ISSN
00-0000-000-0
Start Date
24/09/2013
End Date
27/09/2013
From page
710
To page
710
Proceedings 18th International Nondestructive Testing and Evaluation of Wood Symposium. Madison, Wisconsin, USA 2013
Participants
  • Autor: Daniel Fernandez Llana (UPM)
  • Autor: Sergio Jose Sanabria Martin (Wood Physics, ETH Zurich, Switzerland)
  • Autor: Guillermo Iñiguez Gonzalez (UPM)
  • Autor: Francisco Arriaga Martitegui (UPM)
  • Autor: Peter Niemz (Wood Physics, ETH Zurich, Switzerland)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Construcción con Madera
  • Departamento: Construcción y Vías Rurales
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