Dynamic properties of hybrid composite structures based multiwalled carbon nanotubes

What is it about?

The present paper investigates an experimental approach concerning the determination of dynamic behavior and damage kinetics of composite materials based on multiwalled carbon nanotubes (MWCNTs), embedded in electrospun reactive nanofibers in the Taylor impact test. Different impact energies have been considered namely; 21J and 39J to investigate the composite response. Projectiles are manufactured from a commercial steel 2071 with a nominal diameter of 50mm and 1600g of weight. The projectile was fired against a composite specimen initially hooked on a cell effort by a compressed gas gun within the velocity of 5m/s and 7m/s. Three types of specimens are considered: (1) MAT1 (carbon fiber reinforced epoxy polymer composite), MAT2 (consists of MAT1 and electrospun Polybenzmideazole- Bismaleimide (PBI-BMI) nanofibermats between carbon fiber layers) and MAT3 (consists of MAT2, where PBI-BMI nanofibermats are reinforced with multiwalled carbon nanotubes (MWCNTs)). The effect of the MWCNTs on the dynamic properties of the composite structures was studied. Microscope observations reveal damage progressive, buckling and crush-front propagation during tests. Application of the PBI-BMI reactive nanofibermats reinforced with MWCNTs leads to damage prevention, reducing damage area in composite samples

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Why is it important?

Experimental studies of dynamic tests (low impact) were conducted on specimens of carbon / epoxy with and without of electrospun PBI-BMI nanofibermats and MWCNTs. This study was carried out to investigate the effect of CNTs addition on the mechanical properties of composites and the absorbed energy impact. Furthermore, the detection of the maximum force and the damaged size of the specimens after the impact tests were done. The following conclusions are drawn from this study: • Inclusion of reactive electrospun nanofiber mats between carbon fabric layers led to increase the maximum force over the neat composites from 6738.5 to 14158.5 N, by factor 2.1 at low velocity. • Insertion of MWCNTs into fiber structure led to the further increasing maximum force (up to 15953.5 N) • Effect of MWCNTs insertion is more visible at higher velocity, increasing the maximum force from 5503 N for pure composite to 11804.5 N for MWCNTs containing composite (215 %), when nanofiber mat without nanotubes increased maximum force on 37.5 % only, to 7566 N. • Combination of 3D crosslinking in composites with addition of CNTs showed a significant improvement in impact performance. MWCNTs embedding decreased the size of damaged area in the composites. It also resists to the damage evolution and cracks propagation.

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