Load Duration Effects in Wood at High Strain Rates
Publication: Journal of Materials in Civil Engineering
Volume 25, Issue 11
Abstract
Strain rate can significantly affect the strength of materials. The split-Hopkinson pressure bar (SHPB) was initially utilized to study the effects of high-strain rate () on the behavior of metals. Subsequent modifications to the original technique allowed the study of brittle materials such as ceramics, concrete, and rock. Although material properties of wood for static and creep strain rates are readily available, data on the dynamic properties of wood are limited. Previous work using the SHPB technique with wood has considered only a few conditions, and tests to prove the applicability of the SHPB on wood have not been performed. In this study, tests were conducted using a large diameter [75-mm (3.0-in.)] SHPB. Hard maple specimens, consisting of sugar maple (Acer saccharum), black maple (Acer nigrum), and eastern white pine (Pinus strobus) specimens were utilized to represent a dense hardwood and a low-density soft wood. Specimens were machined to diameters of 63.5 and 75-mm (2.5 and 3.0-in.) and an assortment of lengths were tested to determine the appropriate specimen dimensions. Stress/strain curves were generated from the SHPB data and validated with 6061-T6 aluminum and wood specimens. Stress was indirectly corroborated with gauged aluminum specimens. Specimen strain was assessed with strain gauges, digital image analysis, and measurement of residual strain to confirm the strain calculated from SHPB data. The SHPB was found to be a useful tool in assessing the material properties of wood subjected to compression for high strain rates () and short load durations (70–150-μs). Specimens loaded in the longitudinal direction of 38-mm (1.5-in.) length and specimens loaded in the radial and tangential directions of 13-mm (0.5-in.) length were found to be most applicable to SHPB testing. The data resulting from this study show that the short duration region of the Madison curve is reasonable for high strain rate compression of wood over the range of specific gravities considered.
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Information & Authors
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Published In
Journal of Materials in Civil Engineering
Volume 25 • Issue 11 • November 2013
Pages: 1647 - 1654
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Jan 17, 2012
Accepted: Oct 4, 2012
Published online: Oct 15, 2013
Published in print: Nov 1, 2013
Discussion open until: Mar 15, 2014
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