Improvements In The Fracture Cleavage Testing Of Adhesively-Bonded Wood

Previous researchers have used the contoured dual cantilever beam, DCB, to demonstrate the value of fracture testing for bonded wood. However, use of the contoured specimen is laborious and stringent, preventing the routine application of this powerful test. A simplified method for mode I fracture testing of adhesively-bonded wood is presented here. Two significant improvements are shown: 1) data analysis using a shear corrected compliance method derived from beam theory, and 2) the flat DCB geometry. The shear corrected compliance method is both simple and robust, accounting for variations in wood modulus that often confound traditional shear mode tests. The flat DCB geometry greatly simplifies sample preparation, eliminating difficulties associated with the preparation, calibration, and wood selection that are required with the composite contoured DCB. Real-time crack length measurements required for the flat geometry are routine using digital hardware. The sensitivity and simplification of the method are presented in hopes of promoting the wider adoption of fracture testing for bonded wood