芳纶纤维增韧碳纤维-泡沫金属夹芯梁压缩性能及界面性能

Compression performances and interfacial properties of carbon fiber-foam metal sandwich beams with aramid fiber toughening

为研究芳纶短纤维对复合材料夹芯材料/结构的界面及性能的影响,对具有芳纶短纤维增韧界面的碳纤维-泡沫铝夹芯梁进行了试验和细观增韧机制研究。在夹芯梁制备过程中,在碳纤维-泡沫铝界面加入低密度芳纶短纤维薄膜,通过短纤维的桥联作用,提高夹芯梁的界面黏接性能。研究了芳纶纤维增韧对夹芯梁面内压缩性能和破坏模态的影响,采用非对称双悬臂梁(ADCB)试验测量了不同增韧参数条件下,碳纤维表板与泡沫铝芯体之间的临界能量释放率。试验结果显示:在相同增韧参数条件下,Kevlar纤维增韧夹芯梁的面内压缩性能和界面临界能量释放率均较好,而混杂长度Kevlar纤维的界面增韧效果最优。通过对试件断面的SEM观测,分析了芳纶纤维增韧的细观增韧机制。

To fully understand the underlying toughening and reinforcing effect of short aramid fibers to interfacial and structural properties of composite sandwich structures,experimental studies were carried out for investigating toughening effects and mechanisms of aramid fiber interfacial toughening on a sandwich beam,consisting of an foam aluminum covered with two carbon fiber/epoxy composite surface layers.Low-density short aramid fiber films were inserted at the interface during the sandwich fabrication process,to improve the interfacial bonding properties through the bridging effect of short fibers.In-plane compression tests were carried out to investigate the effect of short aramid fibers on structural properties and failure mode of sandwich beam.The critical energy release rates of face-core interface with various toughening parameters were measured under asymmetric double cantilever beam(ADCB)condition.According to the results,the in-plane compression strength of sandwich beams and critical energy release rates between face sheet and core were all improved for all specimens toughened with short Kevlar fibers,especially for specimens toughened with hybrid-length short Kevlar fibers.The interfacial toughening performanceand underlying mechanisms for short aramid fiber toughening were discussed and analyzed using SEM.