UBC Theses and Dissertations
Fatigue behaviour and size effect perpendicular to the grain of laminated Douglas fir veneer Norlin, Lars Peter
The rolling shear behaviour of laminated Douglas fir veneers was studied using specimens with 15 layers of 2.5 mm veneers. The 3 central layers were cross-plies with grain angle oriented perpendicular to the long axis of the specimen. The other layers were orthogonal to the central layers. Based on three specimen sizes, the width effect and load configuration effect for rolling shear failures of laminated veneer panels subjected to "flatwise" three-point bending was experimentally and theoretically evaluated. The rolling shear fatigue performance of the specimens was studied through cyclic testing until failure. Series of specimens were tested at three mean stress levels, 95%, 91%, and 83% of the of the mean static strength. A damage model which took the stress history into consideration was calibrated to the experimental data. Good agreement between model predictions and experimental results were obtained. Using a size adjustment factor, the model was verified by two cyclically tested series of specimens of different size. The size adjusted model predictions were found to agree well with the experimental data.
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