Laboratory Investigation of Higher Order Elastic Coefficients in Timber

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Peterson, M.
Mittlestadt, C.
Downs, J.
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Review of Progress in Quantitative Nondestructive Evaluation
Center for Nondestructive Evaluation

Begun in 1973, the Review of Progress in Quantitative Nondestructive Evaluation (QNDE) is the premier international NDE meeting designed to provide an interface between research and early engineering through the presentation of current ideas and results focused on facilitating a rapid transfer to engineering development.

This site provides free, public access to papers presented at the annual QNDE conference between 1983 and 1999, and abstracts for papers presented at the conference since 2001.


Timber bridges are used on all types of rail lines including important main transcontinental routes. The large number of these structures makes it critical that the limited maintenance funds available be targeted to structures in greatest need of repair. A combined structural dynamic and ultrasonic inspection approach has been proposed for identification of suspect structural members and in-situ evaluation of suspect elements [1]. Results of preliminary field tests were presented which showed the potential for this technique. Dynamic excitation of the system is used for a global test to identify suspect elements in the bridge system. Ultrasonic inspection is used for more extensive local evaluation of the suspect elements identified in the global testing. Preliminary testing of a single bridge member using an ultrasonic technique was shown to be possible under field conditions. This work extends these concepts to a small scale laboratory investigation to test the validity of the method used. The concept of higher order elastic coefficients for strength prediction is explored. It is found that the performance of these measures is not superior to the prediction of strength by elastic coefficients. Initial ideas are presented on the apparent success of techniques used in commercial testing equipment which use purely elastic measures of the properties of wood. These elastic properties are used for the prediction of wood strength by wood scientists. Future areas of exploration are suggested.

Wed Jan 01 00:00:00 UTC 1997