屈曲模态对含缺陷复材加筋板后屈曲的影响

某些结构类型的复合材料加筋板，由于一阶和二阶屈曲载荷十分接近，在压缩失稳时，相同的试验件会出现不同的失稳模态，并表现出明显不同的后屈曲承载能力。就此问题，进行了试验和数值模拟研究。轴压试验中，通过影像云纹法和超声C扫技术监测试验件的失稳模态及缺陷扩展情况，以确定不同失稳模态对相同试验件后屈曲承载能力的影响。基于ABAQUS软件建立有限元模型，采用虚拟裂纹闭合技术（VCCT，Virtual Crack Closure Technology）模拟含预置脱胶缺陷的筋条-蒙皮界面，将失稳波形以几何扰动的形式引入后屈曲分析。通过分析缺陷前缘应变能释放率，研究两种模态下缺陷扩展特性。计算结果与试验结果相吻合，研究表明两种模态下缺陷的扩展特性明显不同，导致该型加筋板在3个半波失稳模态下的后屈曲承载能力明显高于2个半波模态下的后屈曲承载能力。

Effect of buckling mode on performance of post-buckled composite stringer-stiffened panels with debond

Because of the proximity of first and second buckling load, some specific stringer-stiffened panels will exhibit different buckling modes under uniaxial compression load, which causes their post-buckling behavior strikingly different. Test and numerical calculation was conducted to study this phenomenon. Moiré interferometry and ultrasonic scan were used to monitor the buckling mode and debond. Based on the software of ABAQUS, a finite element was developed. Virtual crack closure technology (VCCT) was used to simulate the interfaces with artificial debond. The initial geometric imperfection was led into model to process the nonlinear post-buckling analysis. By comparing the strain energy release rates of the crack front, the performance of debond propagation in two different modes was determined. The calculated results are coordinated with the tested results very well. The results indicate that the different damaging propagates under two buckling modes will generate that strength of panels with three half waves buckling mode exceeds the panels with two half waves buckling mode.