| Modern warfare has high requirements on the protection performance of tanks and other vehicles.The composite armor greatly improves the performance of the original metal armor.While the vehicle only uses metal armor,the mobility performance is greatly reduced because of the heavy weight of metal for increasing the protection performance.Ceramic/metal composite armor has become a research hotspot because of ceramic’s low density,high hardness and high strength.With the rapid development of computers,numerical simulation has become the main method to study this problem.However,with the high-speed impact of ceramic fragmentation,finite element method,finite difference method and other numerical methods based on the theory of continuum mechanics are difficult to clearly simulate crack growth and particle spatter.In recent years,Dr Silling proposed peridynamics.Because of the adoption of differential-integral equations instead of the classic differential equations,it reduces the requirement for control equation of continuity,which can effectively lower the processing discontinuity problems such as crack.It reflects potential power of peridynamics method as a penetration simulation tools.In this paper,the penetration problem of ceramic/metal composite target plate is modeled and studied by using the state-based peridynamics method.The main research contents of this paper include:1.Validation of peridynamics analysis penetration resistance behavior of ceramic/metal composite structure: through the analysis of the constitutive model of Peridigm provide,the proper constitutive models of metal,ceramic,and the projectile respectively are chosen.The classical model of peridynamics and finite element models of aluminum/4340 steel composites are established,and the process of projectile penetration into the composite structure with a mass of 9.6g and a velocity of 850m/s is simulated by using the peridynamics and finite element methods respectively.Finally,the peridynamics analysis results of the crack propagation mode,the angle of the ceramic cone,the particle spatter mode and the residual velocity of the projectile are compared with the results of the control experiment and the finite element analysis.The results of peridynamics simulation are in good agreement with the results of the control experiment.The results show that the peridynamics method can accurately and effectively simulate the whole process of penetration of ceramic/metal composite target plate.2.Analysis of convergence and applicability of peridynamics method for calculating the penetration resistance of ceramic/metal composite structures: for the control experiment,a model of different particle spacing is established to study the convergence of particle spacing on the calculated results.The results show that the smaller the particle spacing is,the closer it is to the actual results.The applicability of the influence function and m convergence are studied by choosing proper particle spacing and using different influence function and horizon.The simulation results show that the parabolic decay influence function is most suitable for high-speed impact.For m convergence,when the horizon is equal to 3 times the particle spacing,the peridynamics simulation results are consistent with the experimental results.3.Research on penetration resistance behavior of ceramic composite armor based on peridynamics:(1)Study the crack damage evolution rule of ceramic/metal composite target plate under the impact from low speed to high speed.The results show that the crack propagation patterns at different speeds are consistent with the damage mechanism of the ceramic composite target plate.(2)The remaining velocity of the projectile after high-speed impact is obtained with a certain total thickness and surface density,and the optimal thickness ratio is analyzed.The results show that there are inflection points in the velocity changes of the projectile at different thickness ratios,which are in the same trend with the results of finite element calculation,and further verify that the peridynamics method can be used for quantitative analysis.(3)The special crack propagation mode and residual velocity of brick composite structure are obtained by exploratory research on the penetration resistance of brick composite structure.The results show that the performance of the brick target plate is better than that of the common target plate,and the peridynamics is proved to be suitable for studying the special crack propagation mode of complex ceramic composite armor with multi-module interaction. |
