Abstract
Splitting of wood loaded perpendicular to the grain is a critical issu in timber engineering, and the splitting and failure of wood at its connection are studied in some articles. But to research the characterization and to evaluate that fracture is very difficult. Now we have no standard method to determine the fracture toughness of wood for timber engineering. So we need some simple or useful methods.
Thus we conducted CT test with some woods for structural glulam. Durning the tests, we checked behaviour of crack on the surfaces. We understood that fracture of wood starts at maximum load or after that, but the propagation is unconstant. Then we caluculated JIC, and comparised with some past results. Additonally we studied the relationship between the work-energy and crack length.As a result, we proposed that crack initiation point is almost at maximum load in CT tests. And we understood followings,
1)Crack length (a0/W=0.5-0.6) is useful to calculate lower limit of JIC in CT test.
2)To calculate J-integral, we need FEM-analysis with in-depth element properties
