Tensile strength model of bamboo srimber by 3-p-b fracture test on the basis of non-LEFM

Abstract Bamboo scrimber is an excellent model material for systematic and fundamental material studies of unidirectional fiber composites because of their availability and easiness in sample preparations. This work presented a simple model to obtain the real tensile strength ft of bamboo scrimber by the three-point-bending (3-p-b) fracture test on the basis of non-linear elastic fracture mechanics (non-LEFM). The linear function between the peak load Pmax and equivalent tensile area Ae was constructed with ft as its slope, in which Pmax was obtained from the test and Ae was determined by specimen geometry and material micro-structure. One important advantage of the model was that it is zero-axial, what needed was another point determined by the experiment data. On another hand, quasi-brittle fracture existed in both notched and un-notched 3-p-b specimens of bamboo scrimber because of their surface cut or defects. With the determined ft by notched specimens, the defect size could be calculated, which was linked with dav. Good agreement between the calculated results and microscopic measurements was achieved. Moreover, the easy method in this study could be extended to other unidirectional fiber composites.