碳纤维复合材料低速冲击荷载光纤光栅准确获取理论及其损伤识别方法

As a strategic advanced materials, the carbon fiber reinforced plastics (CFRP) composite material is of significance to the national security. However, due to the laminated structures of CFRP, some concealed internal damage may occur in the materials when suffering from low-velocity impacts, and then induce potential risks. In order to solve the issue, the fiber Bragg grating (FBG) will be embedded into the CFRP to monitor the internal damage. We will reveal the stress coupling relation between the FBGs and the materials, study the delay compensating model, and investigate the chirp identification and removal method for FBG. By doing so, the FBG based dynamic signal sensing for the CFRP will be solved. Then, the stress wave adaptive velocity model including directions, frequency, and temperature will be studied for the CFRP under low-velocity impact. And stress wave preprocessing methods, composes of correlation analysis, frequency extraction and deconvolution, is proposed to accurately locate the impact loads. Additionally, the impact loads will be reconstructed using linear auto regression dynamics analyzing method based on the wavelength variation of the embedded FBGs. And the mathematical relation between the key parameters of impact signals and the damages of the CFRP will be revealed. Finally, a comprehensive methodology and system for the damage identification and early-warning of CFRP will be formed.

碳纤维复合材料作为关系国家安全的战略性新材料，由于其层合结构特点，易受低速冲击荷载形成隐蔽性极强的内部损伤，造成巨大的安全隐患。针对上述问题，本项目将光纤光栅植入碳纤维复合材料内部，揭示光纤光栅与碳纤维复合材料的应力耦合匹配关系，建立光纤光栅与复合材料之间的时间补偿模型，形成光纤光栅啁啾效应识别与剔除新方法，率先突破碳纤维复合材料中光纤光栅动态信号高精度传感与获取难题。在此基础上，建立包括方向、频率、温度等参量的碳纤维复合材料低速冲击应力波自适应传播速度模型，提出包括相关分析、主频提取、反褶积的三步应力波分析预处理方法，实现复合材料低速冲击荷载的准确定位。并进一步基于光纤光栅中心波长的变化，采用基于线性自回归动力学分析方法实现冲击荷载的重建，揭示冲击荷载主要表征信息与碳纤维复合材料损伤程度之间的关系，形成碳纤维复合材料损伤识别与预警综合方法和体系。

针对碳纤维的层合结构易受低速冲击荷载形成隐蔽性极强的内部损伤关键问题，以精确速度模型的损伤准确定位与损伤识别为目标，研究了光纤光栅低速冲击信号的高精度获取方法，突破了碳纤维复合材料中光纤光栅动态信号高精度传感与获取难题；研究了基于精确速度模型的碳纤维复合材料低速冲击准确定位理论与方法，建立了包括方向、频率、温度等参量的碳纤维复合材料低速冲击应力波自适应速度传播模型，提出了包括相关分析、主频提取、反褶积的三步应力波分析预处理方法，实现了复合材料低速冲击荷载的准确定位；进一步研究了碳纤维复合材料损伤识别与预警方法，揭示了光纤光栅中心波长与复合材料冲击荷载主要表征信息(能量、频率)的转换关系，阐明了不同阶段冲击荷载主要表征信息与碳纤维复合材料损伤程度的变化规律，建立了基于光纤光栅的碳纤维复合材料损伤识别与预警综合方法和体系，并开展了现场试验，为软碳纤维复合材料损伤定位、识别和预警提供了支撑。项目发表论文30篇，其中SCI检索论文26篇，授权国家发明专利5项，培养博士研究生5名、硕士研究生5名。