Examination of the Mode II fracture behaviour of wood with a short crack in an asymmetric four-point bending test

• Published in: Engineering fracture mechanics Vol. 78; no. 16; pp. 2775 - 2788
• Main Authors: Susanti, Cicilia Maria Erna, Nakao, Tetsuya, Yoshihara, Hiroshi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2011; Elsevier
• Subjects: Applied sciences; Asymmetric four-point bending test; Asymmetry; Bend tests; Correction crack length; Exact sciences and technology; Failure; Fracture mechanics; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Mode II stress intensity factor; Physics; Polymer industry, paints, wood; Shear strength; Short crack; Short cracks; Solid mechanics; Stress intensity factor; Structural and continuum mechanics; Wood; Wood. Paper. Non wovens; Correction crack length; Shear strength; Short crack; Mode II stress intensity factor; Asymmetric four-point bending test; Wood; Test bar; Modeling; Shear fracture; Stress intensity factor; Asymmetry; Precracked specimen; Crack length; Crack tip; Strength; Bending test
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2011.07.014

Asymmetric four-point bending tests of agathis specimens with a short crack along the neutral axis in a tangential–longitudinal system were conducted onto analyse the failure behaviour of wood with a short crack. The nominal shear strength and Mode II critical stress intensity factors of the specimens with various crack lengths were measured, and the influence of crack length on these properties was examined. The nominal shear strength of the cracked specimens was significantly lower than the strength of a crack-free specimen, even when the crack was extremely short. This finding suggests that the fracture mechanics theory is effective for analysing the failure behaviour of wood with a very short crack in this loading condition. However, the Mode II critical stress intensity factor still depends on the crack length. When the crack length was corrected with considering the formation of fracture process zone ahead of the crack tip, the critical intensity factor could be predicted effectively as well as the nominal shear strength.