Author(s):
Moura, M. F. S. F. de 
; Silva, M. A. L. ; Morais, J. J. L. ; Morais, A. B. de ; Lousada, J. L.
Date: 2006
Persistent ID: http://hdl.handle.net/10773/5717
Origin: RIA - Repositório Institucional da Universidade de Aveiro
Description
In this study, the End Notched Flexure (ENF) fracture test was used to obtain the mode II Rcurve of the Pinus pinaster wood in the RL crack propagation system. The test method was
numerically and experimentally analyzed. In the numerical study, three (3D) and twodimensional (2D) finite element analyses were conducted to determine the mode II critical strain energy release rate (GIIc) and the respective R-curve. Firstly, the 3D analysis was performed in order to obtain the strain energy release rates distributions at the crack tip, and
consequently, to identify the presence of spurious fracture modes that could affect the
measured GIIc. The P-δ-a values determined from the 3D model were compared with the same
values obtained from the 2D model. The main objective was to validate the 2D model, which
is computationally less expensive. On the other hand, measurement of the crack length in the ENF test is quite difficult in wood because crack tends to close during propagation. To avoid this experimental problem a Compliance-Based Beam Method (CBBM), based on equivalent crack approach, is proposed. Moreover, this method does not require additional experimental tests to obtain the elastic properties. Experimental tests were also executed in order to verify
the numerical results. The aim is to introduce the CBBM as a standard data reduction scheme in order to measure the GIIc value.
