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.

中文翻译：

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基于非LEFM的3-pb断裂试验竹纤维抗拉强度模型

摘要 竹编排器是一种很好的模型材料，用于单向纤维复合材料的系统和基础材料研究，因为它们的可用性和样品制备容易。这项工作提出了一个简单的模型，通过基于非线性弹性断裂力学 (non-LEFM) 的三点弯曲 (3-pb) 断裂试验来获得竹编布的真实拉伸强度 ft。峰值载荷 Pmax 与等效拉伸面积 Ae 之间的线性函数以 ft 为斜率构建，其中 Pmax 由试验获得，Ae 由试样几何形状和材料微观结构确定。该模型的一个重要优点是它是零轴的，需要的是由实验数据确定的另一个点。在另一方面，由于其表面切割或缺陷，竹疏编机有缺口和无缺口的3-pb试样均存在准脆性断裂。通过缺口试样确定的 ft，可以计算缺陷尺寸，这与 dav 相关联。在计算结果和显微测量之间取得了良好的一致性。此外，本研究中的简单方法可以扩展到其他单向纤维复合材料。