Mode II critical stress intensity factor of solid wood obtained from the asymmetric four-point bend fracture test using groove-free and side-grooved samples

Asymmetric four-point bend fracture (AFPBF) tests and three-point bend end-notched flexure (3ENF) tests were performed on groove-free and side-grooved samples of western hemlock, and the Mode II fracture critical stress intensity factor (K-IIc) was obtained. Differences in the K-IIc values obtained from the AFPBF and 3ENF tests were significant. However, these differences were effectively reduced when the additional crack length Delta was introduced into the data reduction process. These results indicate that the K-IIc value can be determined by considering the Delta value and the results obtained from previous Mode II fracture mechanics tests.