Study On Damage Mechanism And Anti-penetration Performance Of Bulletproof Glass Under Ballistic Impact

Multi-layer bulletproof glass with sodium calcium silicate glass as the main material has excellent impact resistance,light transmittance,and low production cost.It has been widely used in military and civil protection fields.With the progress of technology,the modern battlefield puts forward higher requirements for the impact resistance and lightweight design of bulletproof glass.However,inorganic glass is a highly brittle material with complex fracture and damage behavior.As a result,the design and optimization of bulletproof glass mostly depend on repeated tests and battlefield experience,which hinders its development to some extent.At present,the understanding of the constitutive characteristics and failure mechanism of glass materials is far less than that of traditional metal materials.In particular,the damage characteristics and anti-penetration mechanism of bulletproof glass in the process of bullet penetration are not clear.In this paper,typical bulletproof glass is selected as the research object,and the damage mechanism and anti-penetration performance of bulletproof glass under ballistic impact are studied by combining theory,experiment and simulation.Firstly,the static / dynamic uniaxial compression test of soda lime silicate glass was designed,and the compressive strength of the material at different strain rates was obtained.The strain rate effect was discussed,and the JH-II constitutive model of the material was constructed.The nonlinear finite element software LS-DYNA was used to simulate the Hopkinson pressure bar(SHPB)test process,and the validity of the constitutive model was verified.The broken glass samples under static / dynamic compression were recovered.The results of scanning electron microscopy(SEM)showed that the cross section of the glass showed local plastic characteristics under dynamic load,including shear yield bands and particle pullout.Then,the ballistic impact tests of two typical bulletproof glass were carried out,and the damage mechanism of the standard rifle bullet to the bulletproof glass was analyzed,including the damage characteristics of the projectile target,the crack propagation law of the glass,the interaction between the adhesive layer and the glass,and the penetration depth law of the bullet multiple shooting.Based on the experimental results,a prediction model of penetration depth of bulletproof glass considering the relative position of impact point is proposed.The experimental data are in good agreement with the model prediction.Finally,the ballistic impact process of a bulletproof glass was simulated by the finite element method.The response mechanism of the bullet and the target plate and the propagation characteristics of the stress wave during the penetration process were analyzed.The influence mechanism of the interlayer mechanical properties on the anti-penetration performance of the bulletproof glass structure was studied by parameter design.It was found that the antipenetration performance of the bulletproof glass increased with the increase of the normal/tangential bonding strength and failure strain of the adhesive layer.