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复合材料胶接结构损伤变形和演化行为的实时表征对其服役的安全性和可靠性评估具有重要的意义。结合数字图像相关(Digital Image Correlation,简称“DIC”)和声发射(Acoustic Emission,简称“AE”)技术,研究循环拉伸加载条件下复合材料单搭接界面的损伤变形与破坏行为。依据单向拉伸失效载荷均值,取准静态破坏载荷的70%和80%分别进行循环拉伸加载实验。通过不同阶段复合材料胶接界面的损伤变形场、应变场信息及演化过程中获取的AE信号,分析循环加载下复合材料单搭接界面损伤破坏的力学机制与实时变形和AE特征信号的对应关系。结果表明,复合材料单搭接试件损伤破坏的实时微位移场特征和AE相对能量、撞击累积数及幅度谱等反映了胶接界面微裂纹的萌生及扩展行为。随应力水平的升高,复合材料单搭接试件破坏前的循环次数呈递减趋势。
The real-time characterization of the damage deformation and evolution behavior of composite cementitious structures is of great significance for the assessment of their service safety and reliability. Combining the digital image correlation (DIC) and Acoustic Emission (AE) techniques, the damage deformation and failure of the single lap interface of composites under cyclic tensile loading were studied. behavior. Based on the uniaxial tensile failure load average, 70% and 80% of the static failure load were taken as cyclic tensile loading test. Through the damage deformation field, strain field information and AE signal acquired in different stages of the bonded interface of composite materials, the corresponding relationship between the mechanical mechanism and the real-time deformation and AE characteristic signals of the damage interface of the single lap interface under cyclic loading was analyzed . The results show that the real-time micro-displacement field characteristics, the relative energy of AE, the cumulative number of impact and the amplitude spectrum of single-lap composite specimens reflect the initiation and propagation of microcracks at the interface. With the increase of stress level, the cyclic number of single lap composite specimens before destroying decreases gradually.