Failure Mechanics of a Composite Laminate Embedded with a Fiber Optic Sensor
Failure Mechanics of a Composite Laminate Embedded with a Fiber Optic Sensor
复制标题
嵌入光纤传感器的复合材料层压板的失效机制
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Bhargava
中科院分区：
文献类型：
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作者：
K. Shivakumar;A. Bhargava
垂直于增强纤维嵌入的光纤传感器（FOS）会导致“眼”形缺陷。眼睛的长度约为光纤半径（RFOS）的16倍，高度约为2 RFOS。眼睛在中心包含光纤，被细长的树脂袋包围。嵌入FOS导致增强纤维在等于6-8 RFOS的高度上的几何变形。该缺陷在树脂袋的根部、光纤和复合材料之间的界面（在复合材料中）以及在复合材料中与载荷方向成90 °处引起严重的应力集中。应力集中是通过代表性的显微照片的有限元建模来计算的。有限元结果与文献中类似问题的分析和实验数据吻合较好。轴向应力集中约为1.44，横向应力集中在界面处为0.165，树脂袋处为0.171。在拉伸载荷作用下，初始失效是由于树脂袋根部的横向基体开裂（纤维劈裂），然后由于纤维断裂导致最终断裂。在压缩载荷下，失效是由于大的横向拉应力引起的界面开裂，最终断裂是压缩。采用最大应力准则分析计算的断裂应力与试验数据吻合较好。
A fiber optic sensor (FOS) embedded perpendicular to the reinforcing fibers causes an ‘eye’-shaped defect. The length of the eye is about 16 times the fiber optic radius (RFOS) and the height is about 2RFOS. The eye contains fiber optics in the center surrounded by an elongated resin pocket. Embedding FOS causes geometric distortion of the reinforcing fiber over a height equal to 6-8 RFOS. This defect causes severe stress concentration at the root of the resin pocket, the interface (in the composite) between the optical fiber and the composite, and at 90 to the load direction in the composite. The stress concentration is calculated by the finite element modeling of a representative micrograph. The FE results agreed reasonably with the analytical and the experimental data in the literature for a similar problem. The stress concentration in the axial direction is about 1.44 and in the transverse direction at the interface is 0.165 and at the resin pocket is 0.171. Under tensile loading, the initial failure is by transverse matrix cracking (fiber splitting) at the root of the resin pocket, then it leads to final fracture by fiber breakage. Under compression loading, the failure initiation is by interfacial cracking due to large transverse tensile stress and the final fracture is by compression. The fracture stress calculated from the analysis using the maximum stress criteria agreed reasonably with the test data.