Mixed-mode (I + II) fracture characterization of wood bonded joints

In this work fracture characterization of wood bonded joints is performed. The main objective is to define a fracture criterion under mixed-mode loading (I + II), in order to provide a safer and reliable design of wood bonded joints. Experimental fracture characterization tests were carried out. For mode I and mode II loading, the double cantilever beam and the end notched flexure tests were selected. Under mixed-mode I + II loading the mixed-mode bending test was used considering different mixed-mode ratios. A data reduction scheme based on the specimen compliance, the beam theory and on a crack equivalent concept was used to overcome the difficulties inherent to the above referred tests. The fracture linear energetic criterion showed to be adequate to describe the fracture envelop with an exception, as discussed in the paper.