"Experimental results of fracture energy and fracture toughness of radiata pine laminated veneer lumber (LVL) in mode I (opening)"

Prediction of load-carrying capacity of notched timber beams can be performed using Linear Elastic Fracture Mechanics (LEFM). However, some material properties such as fracture toughness and energy are needed for the analysis. Unfortunately, due to the complexity of the wood at the micro and macroscopic level, little and sometimes unreliable data are available. Due to the highly anisotropic nature, wood has different fracture properties in three directions. Fortunately, not all of these values are usually required in fracture analysis because the wood tends to crack mainly in grain directions due to the low tensile strength perpendicular to grain. This consideration allows a significant reduction in the number of experiments required for the fracture properties, with considerable saving of resources. The paper presents the results of an experimental study aimed to investigate the fracture toughness of Radiata Pine Laminated Veneer Lumber (LVL) in mode I (opening). Results are presented for the fracture toughness properties in the grain direction, and include five percentile values and Coefficient of Variation (COV). The influence of the specimen size and moisture content on the fracture toughness is also presented. Numerical analyses by use of ABAQUS software were also carried out and compared with the experimental tests showing good agreement. Obtained experimental results are in the range of experimental values found in literature for wood.