Acoustic Emission Activity Induced by Delamination and Fracture of Wood Structure

Abstract

The damage evolution related to fracture phenomena in wood can be expressed at several internal length scales such as atomic, micro, meso and macro scales. Damage initiates on the atomic scale and reaches relevance for larger scales while it propagates, leading to failure when reaching the macro scale. In this section we focus our attention on aspects related to the micro and macro scales. The dominating structure on micro scale is composed from the anatomic constituents while on meso scale the dominating structure is composed from the annual rings. Acoustic emission technique can be used to study the fracture damage mechanisms on micro and meso scales. Acoustic emission analysis requires the analysis of mechanical data and the acoustic emission rate, the localization of the acoustic emission source, the evaluation of the topography of the fracture plane and finally, studies for different failure modes. (Grosse and Finck 2006).