Study On The Static-dynamic Mechanical Properties And Damage Characteristics Of Ceramic Materials

Ceramic materials have excellent physical, mechanical properties, widely used in military armor protection and civil engine et al, and had played an extremely important role in defense and high-tech sector. Study of the mechanical properties, impact properties as well as the damage and failure of ceramic materials become a new trend for protective works at home and abroad. Generally speaking, the study of the ceramic materials is mostly preliminary and scattered, and there is a large gap between domestic research and foreign countries. This article by means of more comprehensive study of the combination of experimental, theoretical and numerical simulation work, study the basic static and dynamic mechanical properties of ceramic materials, as well as damage and failure characteristics, profoundly reveals the mechanism of resistance to penetration of the ceramic material.Thesis carry out the static and dynamic behaviors of the the AD95and AD86/10two kinds of ceramic materials experiments using experimental apparatus (MTS, SHPB, LGG and penetration). Using MTS experimental apparatus obtained the parameters of the strength, Poisson’s ratio, Young’s modulus and the stress-strain curve of the material in the lower strain rate. Using the SHPB experimental apparatus obtained the yield strength of the two kinds of ceramic materials under medium-high strain rate, and found that the strain rate hardening effect. Using the LGG experimental device obtained the free surface velocity-time curve and the spall strength under high strain rates. Using anti-rod penetrated experimental device obtained the thickness protection factor and quality protection factor of the two kinds of materials.Making use of the basic material parameters and the experimental data obtained the ceramic materials’JH-2constitutive model parameters. Two yield criterions were established through theoretical analysis which contain both material strain rate effect and pressure related effects about ceramic materials. Compared the calculation process and the advantages and disadvantages of the radius regression with strict incremental algorithm through analysis. Take the established yield criterion for example, the strict calculation formula of incremental algorithm was deduced in details.Through taking into account the strain rate effect of the projectile and target materials, further improved the engineering analysis method based on the hydrodynamic analogy. The improved engineering analysis method was applied to numerical simulation of the resistance to penetration process of ceramic materials, the simulation results were in good agreement with the experimental results. Dimensional analysis method was applied to get no dimensional form similarity law of model, and established the correction law of similarity when considering the strain rate effect.Numerical simulated axial stress uneven phenomenon of ceramic specimen under SHPB experiment with high strength tungsten carbide inserts, and put forward a reasonable inserts form. The numerical simulation results showed that under the new combination inserts form the axial stress uneven phenomenon of specimen is basically eliminated. Application of one-dimensional stress wave theory got the correction method of experiment data.The tensile damage evolution equation and the compression-shear coupling damage evolution equation of ceramic materials were established. The physical concept of the evolution equations is clear and the undetermined parameters are few. We simulated the free surface velocity time history curve of ceramic materials under plate impact experimentation, using the above-mentioned JH-2constitutive model and parameters, the tensile damage evolution equation and the radius regression algorithm. The parameters in damage evolution equation are obtained by optimization. Application of the damage evolution equation and the parameters, the double exponential yield criterion and the strict incremental algorithm, we simulated the same LGG experiment. The simulation results were good agree with the experimental results, proved that the yield criterion, the strict incremental algorithm and the damage evolution equation are reasonable.