Study On Properties And Failure Mechanism Of CFRE/BFRE Hybrid Composites

The utilization of carbon fiber reinforced epoxy(CFRE)was of great significance to the lightweight of the carrying equipment,but the disadvantages of high price of carbon fiber and low elongation at break restricted its wide range of use.Basalt fiber reinforced epoxy(BFRE)had the advantages of affordable price,which exactly makes up for the shortcomings of CFRE.In this paper,9 hybrid structures and 5 fiber hybrid ratios of carbon fiber and basalt fiber reinforced composite were proposed.The effects of stacked structure and hybrid fiber content ratio on the mechanical properties,inservice performance and failure mechanism of composite materials were analyzed through a combination of experimental,theoretical and predictive model.The details and conclusions of the study were summarized as follows:Firstly,several common damage modes of hybrid composites were revealed.Five types of damage patterns of hybrid composites were revealed progressive damage failure criterion.The stretching properties and tensile fracture failure modes of basalt fiber bundles and carbon fiber bundles were investigated for the fibers composing the hybrid composites.The hybrid structure and hybrid ratio design of hybrid composites and the preparation process of laminates were described in detail.Secondly,the effects of hybrid fiber content ratio and hybrid structure on the mechanical properties of CFRE/BFRE composite laminates were analyzed.The progressive damage process and failure mode of laminates were record and analyzed using digital image correlation(DIC)technique and confocal laser microscopy.The results showed that the fiber ratio and the stacked structure had a significant effect on the peak tensile load,but the hybrid structure had little influence on the tensile modulus.The surface strain of the laminates increased first and then reduced at last.The influence of the hybrid structure on the average surface strain of the hybrid composites was not significant.In the three-point bending test,the fiber ratio and stacked structure had a great effect on the bending peak load and bending modulus.The stacked structure affected the failure mode of the bending resistance test specimen,and showed different failure phenomena on the tensile side and compression side.With the addition of basalt fiber,the failure mode of the CFRE/BFRE hybrid composite material was improved.Lastly,by dynamic tensile test and neutral salt spray corrosion test,DIC,scanning electron microscope(SEM)and energy dispersive spectrum(EDS)techniques were used to study the high speed impact resistance and salt spray corrosion resistance of CFRE/BFRE hybrid composites.The results showed that the effect of hybrid fiber content ratio on the dynamic tensile properties was different at different strain rates.The effect of strain rate on the failure mode was also different.In the neutral salt spray corrosion tests,different type of composites had different corrosion characteristics,but the performance degradation pattern behaved the same.The corrosion failure models of four kinds of composites with better properties revealed the degradation relationship of the composites with corrosion time accurately.