FRACTURE ANALYSIS OF WOOD IN MULTIPLE-PINNED JOINTS USING DIGITAL IMAGE CORRELATION METHOD

摘要

The deformation behavior of wood in multiple-pinned joints was analysed using digital image correlation method (DIC) and finite element method (FEM). The joints were fastened with four dowel type pins of the same diameter. Diagonal compression load, which causes moment and shear around the joints, was applied to the corners of the specimen. DIC was used to obtain 2-dimensional strain distribution of wood around each pin hole. Finite element analysis were carried out to compare the experimental results with that of equal load sharing. For the finite element analysis, orthotropic plane-stress elements were used and material properties were assumed to be linear elastic. Results were as follows. Large compression strain perpendicular to grain and large shear strain were observed in the predicted loading (contacting) area of each pin-loaded hole. Large tensile strain perpendicular to the grain was observed close to the loading area of a pin, and partly overlapped with the area of large shear strain. The overlapped area coincided with the location of initial cracks propagated parallel to the grain. This coincidence suggested that the cracks occurred by mixed-mode fracture in this multiple-pinned joints. The numerical results by finite element analysis were compared with the experimental results obtained with DIC and they are in good agreement with each other.