Visualization of Fresh Cut Timber Deformation by Photogrammetry
Publication: Journal of Engineering Mechanics
Volume 143, Issue 4
Abstract
Understanding the mechanical behavior of fresh cut timber, in which the natural moisture content has been retained, has application in predicting the behavior of living tree elements such as branch/stem joints, potentially inspiring structural designs through biomimicry. This project develops a process of strain imaging using particle image velocimetry to analyze behavior of timber samples freshly cut from oak tree joints and tested in tension. The timber surface was not coated so the fiber response could be visualized directly. Load was applied in steps and different methods for comparing images were trialled, including a sequential method in which strain is accumulated progressively from image to image and a first-to-last comparison. Sample flexibility caused significant deformation in the camera field of view, and so the analysis methodology was modified so that each image was compared sequentially with the first with the target area in the image for strain calculation expanded as the test proceeded. This resulted in strain contour plots able to show the impending failure of the component as the tension is applied.
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Acknowledgments
The first author was supported in her research at the University of Southampton by EPSRC under doctoral training grant funding (Grant No. EP/P504740/1). Particular thanks are due to the Forestry Commission for donating fresh cut tree samples and to Dr. Anthony Lock of the University of Southampton for his advice in developing the program code.
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Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 143 • Issue 4 • April 2017
Copyright
©2016 American Society of Civil Engineers.
History
Received: Mar 26, 2016
Accepted: Aug 9, 2016
Published online: Nov 22, 2016
Published in print: Apr 1, 2017
Discussion open until: Apr 22, 2017
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