石英光纤与树脂界面剪切强度实验研究

Interfacial Shear Strength Between Optical Fiber and Resin

为了克服无法精确控制光纤埋入长度和埋入方向等缺点,重新设计了光纤单丝拔出实验。有限元计算结果表明,新旧方法下,光纤各部分剪切应力的分布规律相同,且各相应应力数值误差不超过5%。根据原理设计了纤维穿透基体的光纤拔出实验模具,并进行了普通单模光纤以及碳涂敷单模光纤与基体材料间界面剪切强度实验研究。光纤单丝拔出实验现象表明,光纤涂敷层与内部包覆层间界面平均剪切强度较低,因该强度值与光纤周围的基体材料上承受的沿光纤轴向的正应力相关,若将光纤埋入到复合材料中去,轴向载荷不宜过大,否则会出现光纤涂敷层和包覆层之间界面剪切剥离,产生裂纹,从而降低整体结构的力学性能。

To control the length and the direction of the embedded fiber,the optical fiber pull-out test is re-designed.According to finite element results,the shear stress distributions on fiber parts during the new designed test are accordance with that of the former ones.The maximum experimental error for conesponding stress is less than 5%.Therefore,a new model with fiber penetrating matrix is designed.Tests are carried out to study the interfacial shear strength between the embedded optical fiber and the matrix.Two kinds of optical fibers,normal single mode fiber and c-coated one,are studied.Fiber pull-out test results show that the mean interfacial shear strength between the coating and the clad is weaker.Since the interfacial shear stress between the coat and the clad is related to the normal stress of the matrix around the embedded optical fiber,the applied normal load on smart composite is limited.Otherwise,once the material is overloaded,flaws are appeared between the coating and the clad of the optical fiber.It decreases the mechanical performance of the formed intelligent structure.