Research On Dynamic Constitutive Parameters And Penetration Properties Resisted To Multi-impact Of UHMWPE Fiber Reinforced Concrete

Based on the background where defense structure requires to resist projectiles multiple impact,this paper researched on penetration properties and mechanism of resisting multiimpact of ultra-high molecular weight polyethylene(UHMWPE)fiber reinforced concrete.It’s of great theoretical and military value for the application design of the new fiber concrete structure and the improvement of its practical protection ability.The research was based on the prior static and dynamic mechanical properties and single impact penetration test of UHMWPE fiber concrete.The path for the ideas and technology as follow: first,to investigate the anti-penetration mechanism and multiple impact effect,multi-impact penetration test was performed;then the dynamic model parameters were researched as the basic of anti-penetration numerical simulation;furthermore,calculation model was tested and the mechanism of penetration was analyzed by numerical simulation of single impact penetration test;final y,to obtain the penetration properties and mechanism of anti-multiple impact of different fiber fraction on different impact velocity,the numerical experiment of multiple impact penetration was developed.The main work and conclusion as follows:(1)A multiple impact test was designed and operated.It was found that the incorporation of fiber could inhibit the destruction of the target,and the reinforced concreted with 0.3% fiber volume had better anti-penetration properties property.However,if the fiber volume continue to increase,the performance of resisting projectiles multiple impact obtained a slight decrease.(2)Based on static and dynamic mechanics test results of UHMWPE fiber concrete,RHT model parameters of this material were studied.By simulating cube compression and tri-axial compression test,complete model parameters obtained from tests correlated well with experimental results,this lay a reliable foundation for the numerical simulation of the anti-penetration problem.(3)Single anti-penetration test calculation model of UHMWPE fiber reinforced concrete was established,and it is validation was checked,then the anti-penetration properties and mechanism were analyzed.Results show that the effect of fiber on antipenetration properties is mainly due to the decreas the crater size,and influence on penetration depth is same as the fiber fraction enhanced static strength of concrete.(4)Multi-impact penetration simulation test of UHMWPE fiber concrete was carried out.It was found that multiple bullets penetration trajectory would have a deflecting aggregation phenomenon in the target body.Fiber incorporation could inhibit the damage of the target body.The fiber volume fraction would improve the anti-penetration properties.The fiber volume of 0.5% of fraction is optimal for multiple impact anti-penetration properties,and 0.3% is suboptimal,but the difference is insignificant.Comprehensive consideration the multi-impact penetration test,0.3% of the fiber volume fraction of UHMWPE fiber concrete of concrete comprehensive anti-projectile performance is optimal.