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

制备了单硼包埋树脂基样品，并在室温下对纤维进行了拉出、推入和脉动循环加载试验。对纤维/树脂基体界面周围的应力场进行了有限元分析。所得主要结果总结如下：(1)实测荷载-位移响应与前人实验结果定性一致，证明了本实验方法的有效性。(2)拉、推两种荷载方式对第一次分离荷载点所对应的最大剪切力和后续架架位移过程中所对应的力以及界面处后续剪切位移阶段的荷载变化不大。(3)建立了纤维/树脂-基体界面应力场有限元模型。计算结果表明，纤维在顶面一侧受力的界面处，剪切应力和拉伸法向应力在顶面附近达到最大，并随着距离顶面的远近而减小。这似乎导致了纤维和树脂基质在顶部表面附近的第一次分离。(4)脉动循环拉力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.