Study On High ImpactPerformance Of Shear Thickening Fluid Compostied Fiber Reinforced Polymer Materials

Fiber Reinforced Plastic（FRP）is a new type of high-performance material which is made of fibers made of various materials,and the n compounded with the matrix materials of various chemical raw materials.Because of its outstanding performance and easy change of shape,it has been used in civil engineering and many industries,such as concrete beam and plate structure reinforcement,racing car or spacecraft weight reduction,etc.,but FRP fiber is a brittle material,impact resistant The ability is not good,hindering its application space.Shear Thickening Flour（STF）is a new type of composite material,which is developed from nano particles or micron particles uniformly distributed in dispersants such as peg.STF has excellent shear thickening performance,good viscoelasticity,temperature sensitivity,impact resistance and reversibility.It is often used in making bulletproof vests,dampers and damping fluid for isolation bearings.In order to prepare high-performance STF,a new type of SiO₂/MWCNT-STF hybrid system was prepared by using MWCNT powder as additive.The mechanical properties of the system at high strain rate were analyzed by SHPB high-speed impact.Finally,the effect of MWCNT content on the mechanical properties was given.O n this basis,the high-speed impact mechanical properties of STF composite with GFRP,CFRP,AFRP and BFRP were studied in detail,and the high-speed impact mechanical properties of SiO₂/MWCNT-STF composite with four kinds of FRP were further studied.Through the SHPB experimental study,this paper analyzes the following conclusions:（1）Compared with the mechanical properties of SiO₂/MWCNT-STF and SiO₂-STF under high-speed impact of SHPB,it was found the mechanical properties of SiO₂/MWCNT-STF system were better than those of SiO₂-STF system,but the improvement of mechanical properties of SiO₂-STF did not reach the expected effect,which may be due to the low content of MWCNT.When the system flowed,a large number of SiO₂ particles adsorbed on a small amount of MWCNT,resulting in larger volume and higher mechanical properties Compared with SiO₂-STF,the number of"particle clusters"in SiO₂/MWCNT-STF system is smaller and the average spacing is larger,so the enhancement of intermolecular friction force of SiO₂-STF is not as expected;（2）The mechanical properties of FRP fabric impregnated with STF can effectively improve its mechanical properties under high-speed impact.With the increase of STF concentration,the peak stress and energy peak also increase.The reason is that the fiber gap of FRP-STF sample is filled by STF particles,and the connection between fibers is good.Because STF particles enter into the gap of fiber and act as entanglement point in the destruction,the damage form of fiber is more complex,which is more conducive to the energy consumption of fiber;（3）The mechanical properties of GFRP-STF were improved after adding MWCNT,and with the increase of MWCNT content,the stress peak value and energy peak value of GFRP-STF also increased,which indicated that MWCNT content had great influence on improving the mechanical properties of GFRP-STF under high-speed impact of SHPB.