Share Email Print
cover

Proceedings Paper

Detection and assessment of wood decay in glulam beams using a modified impulse-echo approach
Author(s): Adam Senalik; Megan E. McGovern; Frank C. Beall; Henrique Reis
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

A glulam beam retired from the field and without visible indications of wood decay was used. Towards detection and assessing wood decay, X-ray computer tomography and ultrasonic measurements were carried out. It was observed that decrease in mass density with increasing levels of wood decay affects x-rays attenuation and allows radioscopy to detect and assess wood decay. To detect and assess decay when only one lateral side of the beam is available, a modified impulse-echo was developed. The modified impulse-echo approach is based on observing the dynamic response of the glulam beams to the drop of a steel sphere onto a steel plate coupled to the glulam beam lamina. It was observed that monitoring certain frequency bands allows detection and assessment of wood decay. The selection of these frequency bands requires knowledge of the nominal beam transverse dimensions. Because of the high ultrasonic material attenuation values of decayed wood as compared with those of sound wood, the area under the power spectral density in these frequency bands is smaller in regions of decayed wood. Results show that results from both X-ray computer tomography and impulse-echo measurements are consistent with each other and can be used to detect and assess wood decay in structural lumber.

Paper Details

Date Published: 30 March 2009
PDF: 12 pages
Proc. SPIE 7292, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2009, 72920Y (30 March 2009); doi: 10.1117/12.814866
Show Author Affiliations
Adam Senalik, Univ. of Illinois at Urbana-Champaign (United States)
Megan E. McGovern, Univ. of Illinois at Urbana-Champaign (United States)
Frank C. Beall, Univ. of California, Berkeley (United States)
Henrique Reis, Univ. of Illinois at Urbana-Champaign (United States)


Published in SPIE Proceedings Vol. 7292:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2009
Masayoshi Tomizuka, Editor(s)

© SPIE. Terms of Use
Back to Top