Comparative Analysis of the Elastic Constants Measured via Conventional, Ultrasound, and 3-D Digital Image Correlation Methods in Eucalyptus globulus Labill.

Abstract

The design of engineering high value-added products and timber structures analysis requires reliable elastic characteristics related to a theoretical model that describes the elastic behavior of wood material. The present research focuses on determining the elastic constants of Eucalyptus globulus Labill., which allow their implementation as input parameters in any numerical model. The great potential of this species for novel structural applications was considered due to its superior mechanical properties. Two different testing methods were applied to the same specimens to directly compare the results. These two tests were conventional mechanical compression and a non-destructive ultrasound procedure. In addition, two different strain measurement techniques were contrasted in the performance of the mechanical tests, namely the conventional strain gauges that give local measurements, and the 3-D full-field optical system based on the principles of digital image correlation. The elastic values obtained via ultrasound are higher than those coming from mechanical testing using conventional gauges. Conventional gauges lead to underestimated values in comparison to the results from full-field strain measurements. Eucalyptus globulus shows greater longitudinal and transversal stiffness than the average values for other hardwoods, which verifies the good structural possibilities of this species.