Abstract:  Because of the load monitoring requirements and real-time monitoring problems faced by composite components during service, fiber Bragg grating (FBG) sensors were pasted on the surface of carbon fiber composite materials to measure the strain of carbon fiber composite materials. The bending load size and loading position of carbon fiber composite materials were monitored by establishing theoretical models of strain, load size, and loading position. The method and technical support were provided for overload warning of composite materials in service. The composite components under the bending load, the finite element analysis strain were compared with the theoretically calculated strain to verify the validity of the finite element analysis model, and then the errors between the strain values monitored by the FBG sensor and the theoretically calculated was compared. Finally, the size and position of the bending load subjected to the composite materials were calculated based on the FBG monitoring strain. The results show that under the central load, the maximum error of strain measured by FBG and theoretical calculation value is not more than 16.22%, the maximum error of load size is not more than 10.37%, and the maximum error of load position is not more than 2.83%. Under the action of eccentric 20 mm load, the maximum error of FBG monitoring strain and theoretical calculation value is not more than 10.69%, the maximum error of load size is not more than 13.89%, and the maximum error of load position is not more than 5.70%.

Key words: composite structure, long-span, bending load, load positioning, load monitoring

摘要： 针对复合材料构件服役过程中载荷监测需求及其面临的实时监测问题，将光纤光栅（FBG）传感器粘贴于碳纤维复合材料表面，用于测量碳纤维复合材料应变,通过建立应变与载荷大小、加载位置理论模型，实现了碳纤维复合材料所受弯曲载荷大小及加载位置的监测，为复合材料服役过程超载警示提供方法与技术支撑。在复合材料构件弯曲载荷作用下，首先对比了有限元分析应变值与理论计算应变值，验证了有限元分析模型的有效性，然后对比了FBG传感器监测应变值与理论计算值之间的误差，最后结合FBG监测应变值计算出复合材料所受弯曲载荷的大小及位置。结果表明：中心载荷作用下，FBG监测应变值与理论计算值最大误差不超过16.22%，载荷大小误差最大不超过10.37%，载荷位置误差最大不超过2.83%；偏心20 mm载荷作用下，FBG监测应变值与理论计算值最大误差不超过10.69%，载荷大小误差最大不超过13.89%，载荷位置误差最大不超过5.70%。

关键词: 复合材料结构, 大跨距, 弯曲载荷, 载荷定位, 载荷监测