The Influence of the Inclination of the Crack Plane Relative the Annual Rings Direction on the Cracking Process of Pine Wood

A methodology for determining the critical parameters of pine wood cracking at different angles of inclination of the crack plane relative to the arrangement of early and late wood layers has been developed. The relevant results known to date from scientific literature concerned only two angles of layer arrangement (horizontal RL and vertical TL).To determine the strain energy release rate dependence of susceptibility on crack length for different angles crack plane was used, obtained numerically using the finite elements method. Experimental studies allowed the development of critical relationships between strain energy release rate, crack tip opening width and length of the fracture process zone from the crack plane orientation. Critical values for the strain energy release rate, crack tip opening width, and fracture process zone length were determined. Verification of the results obtained in specific cases of layer arrangement with known literature data showed good agreement.