Investigation On Mechanical Properties Of 2D And 3D Woven Composites And Design Of 3D Sandwich Composite

Fiber Reinforce Composite(FRC) has been developed for more than seventy years.It has been widely used in the industry areas,such as aerospace,automotive, marine engineering,satellites,sports goods,radar antenna cover and so on,for its for their excellent mechanical properties and low density.However,the conventional 2D composite has its limits such as poor mechanical properties through thickness direction,delamination and poor impact properties.All of these shortcomings can be overcome in 3D woven composite.Its through-thickness mechanical properties greatly improved because the Z yarn binds the fiber through thickness.The 3D sandwich composite,which has all above excellent properties,has super low specific gravities.It has great potential application including the areas of higher speed,longer range,largerpay loads,less engine power and better operating economy.This research includes two aspects:"Investigation on Mechanical Properties of 2D and 3D Woven Composites" and "Design of 3D Sandwich Composite".In "Investigation on Mechanical Properties of 2D and 3D Woven Composites" research,glass fiber was used to fabricate perform.When consolidating it,the VARTM method was used and the resin was vinyl resin.The tensile and compressive tests are conducted on 3D orthogonal woven composites and 2D woven laminates to compare the difference of the rigidity and strength of these two composites.The test result shows that the stress-strain curves of both materials are almost linear and they have the characteristics of the brittle failure behavior.Due to the difference of fiber aligned and different structure of composites,the two composites broke in different failure mode.So this causes that the tensile and compression properties of the 3D fabric reinforced composite are better than those of the 2D fabric reinforced composites.In "Design of 3D Sandwich Composite" research,the conventional 3D woven machine was modified.To meet the sandwich structure demand,Six harnesses were used rather than two harnesses.The control program for weaving was redesigned,and some new control programs were added.Then a special drafting method was designed so that 3 kinds of Z-yarn can interlace with the weft yarn.The Kevlar49 and PVC foam were used to make the sandwich preform.When consolidating the preform,the VARTM method was used and the resin was vinyl resin.This unique composite has many advantages such as high strength/stiffness and low density,excellent through-thickness properties,low dielectric constant and low dielectric loss.So it can be widely used in the commercial and industrial areas,which include aerospace, automotive,marine engineering,satellites,sports goods,radar antenna cover and so on.