Transverse fracture toughness of transparent wood biocomposites by FEM updating with cohesive zone fracture modeling
Erik Jungstedt, Sören Östlund, Lars A. Berglund
Abstract
Little is known about fracture toughness of monomer-impregnated wood biocomposites, with no data for transparent wood. For building applications, toughness is important, but the anisotropic nature of wood generates complex stress distributions that needs to be accounted for. A four-point bending fracture mechanics test is combined with digital image correlation (DIC) measurements of displacement fields and finite element model updating. The elastic parameters of an orthotropic composite and the parameters for a cohesive zone fracture model are determined from one transverse crack growth experiment. The fracture toughness for tangential-longitudinal (TL) cracks was lower than expected, as explained by local peeling fracture of the wood cell wall.