Experimental and statistical analysis of carbon fiber/epoxy composites interleaved with nylon 6,6 nonwoven fabric interlayers

2020 ◽  
Vol 54 (27) ◽  
pp. 4173-4184
Author(s):  
Bertan Beylergil ◽  
Metin Tanoğlu ◽  
Engin Aktaş
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Composite Laminates ◽  
Nonwoven Fabric ◽  
Epoxy Composites ◽  
Nonwoven Fabrics ◽  
Mode I Fracture Toughness ◽  
Weight Density ◽  
Nylon 6,6 ◽  
Carbon Fiber Epoxy

Thermoplastic interleaving is a promising technique to improve delamination resistance of laminated composites. In this study, plain-weave carbon fiber/epoxy composites were interleaved with nylon 6,6 nonwoven fabrics with an areal weight density of 17 gsm. The carbon fiber/epoxy composite laminates with/without nylon 6,6 nonwoven fabric interlayers were manufactured by VARTM technique. Double cantilever beam fracture toughness tests were carried out on the prepared composite test specimens in accordance with ASTM 5528 standard. The experimental test data were statistically analyzed by two-parameter Weibull distribution. The results showed that the initiation and propagation fracture toughness Mode-I fracture toughness of carbon fiber/epoxy composites could be improved by about 34 and 156% (corresponding to a reliability level of 0.50) with the incorporation of nylon 6,6 interlayers in the interlaminar region, respectively. The results also revealed that the percent increase in the propagation fracture toughness value was 67 and 41% at reliability levels of 0.90 and 0.95, respectively.

Improved fracture toughness of carbon fiber fabric/epoxy composite laminates using polyether sulfone fibers

2018 ◽  
Vol 31 (8) ◽  
pp. 996-1005
Author(s):  
Wenjian Zheng ◽  
Zhengjun Yao ◽  
Haiyan Lin ◽  
Jintang Zhou ◽  
Haishuo Cai ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Composite Laminates ◽  
Composite Structures ◽  
Secondary Phase ◽  
Average Value ◽  
Mode I Fracture Toughness ◽  
Polyether Sulfone ◽  
The Matrix ◽  
Carbon Fiber Epoxy

This study demonstrated that the addition of dissolvable polyether sulfone fibers to the interlaminar area of carbon fiber/epoxy composites can effectively increase the toughness with very high accuracy. Resin film infusion (RFI) is used to fabricate composite structures. RFI was applied to obtain polyether sulfone as an interleaf of chopped fibers between fabric piles of carbon fibers. The thermoplastic polyether sulfone fiber dissolved in the epoxy when it was cured at a high temperature. A phase-separated morphology with a polyether sulfone-rich secondary phase was formed during the curing process. Experimental results indicated that G Ic, which is the average value of Mode-I fracture toughness, was increased fivefold with the addition of 10 wt% polyether sulfone fiber (with respect to the gross content of the matrix). No detrimental effects were observed in other characteristics such as thermal stability, Young’s modulus, and tensile strength. In addition, the thermal and mechanical characteristics of neat epoxy–polyether sulfone blends were analyzed for comparison.

The Interlaminar Toughening Effect of Hybrid PES/E51 Films on Carbon Fiber/ Epoxy Composite

2020 ◽  
Vol 984 ◽  
pp. 131-136
Author(s):  
Chao Cheng ◽  
Hui Zhang ◽  
Ze Yu Sun ◽  
Yong Liu ◽  
Mu Huo Yu
Keyword(s):  
Fracture Toughness ◽  
Composite Laminates ◽  
Phase Inversion ◽  
Hybrid Film ◽  
Epoxy Composite ◽  
Interlaminar Fracture Toughness ◽  
Resin Infusion ◽  
Mode I Fracture Toughness ◽  
Carbon Fiber Epoxy ◽  
Opposite Tendency

In this study, E51 was appended as an additive to the PES casting solution and hybrid PES/E51 films with different E51 content were produced by phase inversion approach, applied as interleaves to improve the interlaminar fracture toughness of CF/EP composite laminates prepared by vacuum assistant resin infusion process (VARI). The time that the hybrid film dissloved into the epoxy resin depended on the content of E51 in the film, moreover, it was observed that Mode I fracture toughness of the hybrid film modified composite reduced with the addition of E51 compared with the pure PES film interleaved composite, however, the tensile properties showed the opposite tendency. The reason was the reduction in the thickness of the interlayer resin illustrated by cross-section morphologies of all types of laminates.

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