复合材料胶接修补结构疲劳性能的数值和试验研究

为研究室温下复合材料胶接修补结构的疲劳性能,以三维渐进损伤理论为基础,创建了复合材料胶接修补模型,利用材料损伤判断子程序实现对修补结构的静拉伸失效载荷及剩余强度的预测分析,并进行了相关试验的对比分析。采用5种不同尺寸的圆形补片来评价修补效果,并利用超景深仪对修补试件的疲劳损伤扩展模式进行微观测量。结果表明:静载拉伸中,尺寸为3.5r的修补结构承载能力最好;疲劳循环中,尺寸为2.5r的修补结构剩余强度提升效果最好;疲劳载荷下,当循环次数较低时,修补结构的主要损伤为基体开裂,而随着循环次数的增大,主要损伤为纤维断裂。

SIMULATION AND EXPERIMENT ON THE FAILURE MECHANISM OF ADHESIVE BONDING REPAIR IN COMPOSITE

In order to investigate the fatigue behavior of the adhesive bonding repair in composite,the model of adhesive bonding structure with different patch dimension has been constructed based on the three-dimensional progressive damage theory.The ultimate static strength and residual strength of the bonding structure are predicted using damage subroutine,and the comparative analysis of fatigue test and static tensile test were performed.Five circle patches of different dimension are selected for evaluating the repair performance.Meanwhile,the damage degradation mechanism of the patch repair structure under different stress levels with different cyclic loadings is studied by microcosmic measurement.The results reveal that the ultimate static strength of the adhesive bonding structure with the 3.5r patch is better than others.And the residual strength of the adhesive bonding structure with the 2.5r patch is maximal.Under low fatigue cyclic loading,the dominant damage is normally matrix cracking,while fiber breaking is the main damage pattern at the high fatigue cyclic loading for composite materials.