Determining mode II cohesive law of Pinus pinaster by combining the end-notched flexure test with digital image correlation

• R-curve in mode II is determined from CBBM based only on the load–displacement curve.
• Crack tip opening displacement is measured by DIC.
• Finite element analysis of ENF test is carried out using cohesive zone modelling.
• Direct evaluation of cohesive law in mode II is achieved based on CBBM and DIC.

This work addresses the direct identification of cohesive law of Pinus pinaster in mode II. The end-notched flexure (ENF) test is selected for mode II loading. The strain energy release rate in mode II (GII) is determined according to the compliance-based beam method (CBBM) by processing the global load–displacement curve, without requirements to monitor the crack length during test. The fracture test is coupled with digital image correlation (DIC) for the local measurement of the crack tip opening displacement in mode II (wII). Using a direct method, the cohesive law in mode II (σII–wII) is determined by differentiating the GII–wII relationship. The procedure is validated from both numerical, using finite element analyses including cohesive zone modelling, and experimental approaches. The methodology and accuracy on this reconstruction is discussed. It is concluded that the proposed data reduction scheme is suitable for assessing the cohesive law of P.pinaster in mode II.