FINITE ELEMENT FRACTURE PREDICTION FOR WOOD WITH KNOTS AND CROSS GRAIN

A finite element/fracture mechanics model has been developed to predict the tension behavior of structural wood members containing defects. The computer code Starwx presented here is used in a preliminary investigation of the effect of global cross grain on the strength of structural wood members with knots. The results indicate a more severe stress condition for the member with global cross grain as compared to the straight grain member. A method of strength prediction is presented that, unlike other methods, simulates the progressive fracture/failure process in wood, which leads to the ultimate load-carrying capacity of the member. Program Starwx is employed to predict the failure of a wood member containing a knot and global cross grain in a case for which actual test data are available. The member ultimate strength predicted was within 15% of the strength determined by the test.