脱粘尺寸对复合材料单加筋板压缩性能的影响

为确定脱粘缺陷尺寸对轴压载荷下复合材料单加筋板屈曲和后屈曲特性的影响，对4组含不同尺寸脱粘缺陷的工型加筋板进行了试验和数值模拟研究。试验中通过应变测量和超声C扫描等技术手段对试验件的屈曲及后屈曲过程中的变形和缺陷扩展情况进行了监测。基于ABAQUS软件建立了有限元分析（FEA）模型，采用LaRC03准则对复合材料层内损伤进行判定，采用胶层单元对界面脱粘损伤进行模拟，以几何扰动的形式引入失稳波形，利用FEA模型对试验件的屈曲和后屈曲过程进行了模拟。模拟结果与试验结果吻合较好，根据研究结果对试验件的失效过程和脱粘缺陷扩展机理进行了分析与探讨。研究表明，预制脱粘缺陷尺寸大小对试验件屈曲和后屈曲特性影响较大，对最终破坏模式影响不大。脱粘尺寸的增大会导致试验件承载能力的大幅降低，在复合材料加筋结构损伤容限设计中需要着重考虑。 

Effects of debond size on compressional behavior of single-stiffened composite panels

In order to research the effects of debond size on buckling and post-buckling behavior of single-stiffened composite panel under axial compression, four types of I-section stringer-stiffened composite panels containing different debond defects were investigated by test and numerical simulation. Strain measurement and ultrasonic scan were conducted to monitor the deformation and defect propagation in the process of buckling and post-buckling. Finite element analysis(FEA) models were established based on ABAQUS. LaRC03 criteria were introduced for the judgment of intralaminar damage and cohesive elements were used to simulate the damage of the interface between stringer and panel. Buckling wave was introduced by initial geometric imperfection. Processes of buckling and post-buckling of specimens were simulated by the FEA models. The simulated results are coordinated with the test results very well. Failure process and mechanism of debond propagation were analysis and discussed based on the tested and simulated results. The results indicate that debond size has significant effects on the buckling and post-buckling behavior of the specimens instead of the final failure mode. Loading capacity decreases rapidly with the increasing debond size, which needs to be focused on in the damage tolerance design of stiffened composite structures.