Accessible Requires Authentication Published by De Gruyter January 25, 2017

Dynamic hardness of wood – measurements with an automated portable hardness tester

Albert Augusto de Assis ORCID logo, Rogério Pinto Alexandre ORCID logo and Adriano Wagner Ballarin ORCID logo
From the journal Holzforschung

Abstract

A research group on forest products from School of Agriculture – Sao Paulo State University. Brazil developed a portable hardness tester for wood, which is based on a displacement transducer and an embedded electronic processor for dynamic evaluation of hardness. This paper presents the results of calibration tests of the equipment, carried out on seven species of Eucalyptus. A new methodology for dynamic hardness calculation has been introduced, which relays on the reaction force of the indentation, while the measurements of indentation depth are performed under load. A moderate to strong linear correlation to Janka hardness and its variations were found. This new approach avoids the classical problems of Brinell hardness test in terms of “sinking-in” (causing diffuse edges) and elastic recovery of the indentation.

Acknowledgements

The authors express their gratitude for the financial support given by FAPESP – Sao Paulo Research Foundation for the development of this project (08/08414-0).

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Received: 2016-8-29
Accepted: 2016-12-28
Published Online: 2017-1-25
Published in Print: 2017-5-1

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