Numerical analysis on effect of PNF interlayer on CFRP delamination

Abstract

It is proved that porous polyamide non-woven fabric (PNF) can achieve an excellent toughness of the composites while keeping a good processibility. However, there is less research about the interlaminar toughening mechanism of PNF up to now. The finite element model based on cohesive zone model (CZM), which represents the PNF thickness and property, was constructed to predict the delamination onset and propagation of CFRP. In the double cantilever beams test, the main conclusions are as follows:There is little effect of thickness of PNF on the peak load in modeⅠdelamination of CFRP, but the resistance of propagation reaches the maximum when the thickness is equal to 20μm. The shape of the delamination front can be directly obtained from the simulations by studying the distribution of the normal traction. For a specific ply-orientation composite, once delamination begins to propagate, the figure of delamination front is consistent. With the increase of the PNF/CFRP ply angle from[012/012] to[012/9012], the propagation distance and peak load are reduced correspondingly.

Keywords

• composites
• polyamide non-woven fabric
• cohesive zone model
• fracture toughness
• nume-rical analysis