Study On Peel Ply Of Secondary Bonding Of Composites For Wind Power Blade

Wind power is the most promising sustainable energy in contemporary society.The core components of that is the wind power blades,in which the beam cap which is made by carbon fiber reinforced composite is the most important bearing part.Molding wind power blades,pultruded carbon fiber reinforced ribbons will be stacked on the glass clothing that is used for blade skin,and then using Vacuum Assisted Resin Transfer Molding process,which includes vacuum pumping,perfusion resin and curing.The pultruded strips are molded along with the bonding between the resin and the reinforcing fiber,which is referred to the first bonding.The bonding using the resin is referred to the secondary bonding between the pultruded strips stacked in the skin on the blade.As the pultruded strip surface is smooth,the strips used for secondary bonding are close to each other,and the strip space is too small to let the resin fully cover in the secondary bonding process.Leading to poor bonding performance.This paper will study the secondary bonding properties between the striped interface.In this paper,five kinds of nylon peel ply with different structural parameters were selected.The weft yarn distribution density,fabric tightness,fabric density,thickness,volume fraction and fabric weight were measured.Through the geometrical model of the peel ply,the relative buckling wave height of the five kinds of peel ply was calculated.The roughness of the substrate that used the peel ply in the molding process is certainly higher than the substrate without peel ply in that process.Besides that,the tightness of the changed substrate is increasing with relative buckling wave height of the peel ply.In the result,the better the roughness of the substrate,the better the bonding performance.When the peel ply was used in the composite molding process,the stripes were duplicated on the surface of substrate,and the roughness of the surface was decided by the tightness and relative buckling wave height of peel ply.Through the testing of shear strength and failure mode analyzingof interface failure by SEM,to the secondary bonding composite,one of the bonding surface with stripes of peel ply would provide higher shear strength for the composite than the production that bonded from two rough surfaces.Therefore,if we want to get the composite with better boding strength,we just need to make one substrate surface of the peel ply rough.