Evaluation of interfacial strength between base material and fiber in PMC at high temperatures

制备了单根硼包埋树脂基纤维试样，并在室温下对纤维进行了拔出、推压和脉动循环加载试验。有限元分析还进行了检查纤维/树脂基体界面周围的应力场。所得主要结果概括如下。(1)所测得的载荷-位移响应与先前的论文中出现的实验定性一致，证明了本实验方法的有效性。(2)拉、推加载方式对界面处第一次分离时的最大剪切力和随后的货架位移过程中的力以及随后的剪切位移阶段的载荷变化不大。(3)建立了纤维/树脂-基体界面应力场的有限元分析模型。计算结果表明，在界面处，剪切应力和拉伸正应力在顶面附近达到最大值，并随着离顶面的距离的增加而减小，此时纤维在顶面一侧加载。这似乎导致纤维和树脂基质之间在顶面附近的第一分离。(4)脉动循环拉伸试验数据用一种常见的S-N曲线表示。

The single boron embedded resin-matrix sample was prepared, and then pulling out, pushing and pulsating cyclic loading tests were performed for the fiber at room temperature. FEM analysis was also made for examining the stress field around the fiber/resin matrix interface. The main results obtained are summarized as follows.(1) The measured load-displacement response is qualitatively in agreement with the experiment appeared in the earlier paper, evidencing the validity of the present experimental procedures.(2) The maximum shear force and the force in the following shelf-displacement process, which correspond to the load point at the first separation and the load in the following shearing displacement stage at the interface are little changed by load mode of pulling or pushing.(3) The FEM model was constructed for analyzing the stress field around the fiber/resin-matrix interface. The calculation showed that the shear stress and the tensile normal stress reach the maximum around the top surface and decreases with distance from the top surface at the interface, where the fiber was loaded on the top surface side. This seems to cause the first separation between the fiber and the resin-matrix near the top surface.(4) The pulsating cyclic tension test data were expressed by a common type of S-N curve.