The Study Of Quasi-static Deformation And Failure Of PBX Based On Drucker-Prager Criterion

Polymer bonded explosive (PBX) is particulate composite consisting of explosives and polymer binders etc. PBX quasi static deformation and failure research related to the stability and safety of weapon system.The Drucker-Prager criterion is a pressure correlation strength criterion, and it is a circle in the deviatoric plane. It has revised the pressure independent characteristics of von-Mises criterion, and has corrected the singularity problems in numerical calculating of Mohr-Coulomb criterion. Therefore, it is widely used in the numerical simulation of rock and soil material. In view of the fact that the mechanical properties of geotechnical materials and PBX materials are similar, the Drucker-Prager criterion and extended criteria is used to describe the deformation and failure of PBX materials.The corresponding incremental constitutive relationship of the PBX is established, which is based on the Drucker-Prager model and the generalized plasticity theory, combining with the non associated flow potential. The elastic-plastic deformation process of PBX was analyzed. The stress and strain relations of uniaxial compression, uniaxial tension, biaxial compression, biaxial tensile experiment conditions were solved. And they were compared with experimental data and numerical simulation results. Draws a conclusion that the established incremental constitutive relations are quite good for uniaxial compression, uniaxial tension, and draws a conclusion that the biaxial compressive strength is slightly higher than that of uniaxial compression, biaxial tensile strength is slightly lower than the uniaxial tension. The conclusions are consistent with the mechanical behaviors of PBX materials.The damage factor was introduced to the incremental constitutive, namely the Damage plasticity model. The damage factor of PBX materials was normalized from the damage factor of concrete. The parameters needed for the model were determined. That the model is suitable for low plasticity of PBX material, and can describe well with the stress and strain relationship of uniaxial tension and uniaxial compression states. But the description of the PBX Brazil disc is not the ideal state. The accuracy still needs further research, especially to describe the mechanical behavior of the complex stress condition accurately.The temperature bearing capacity of PBX structure was analyzed with no internal pressure thick spherical shell structure. With the corresponding strength criterion, temperature bearing capacity was deduced, and its influence factors was analyzed (The material properties, structure size). The material properties and temperature bearing capacity of three kinds of common PBX materials at home and abroad (The United States PBX-A, British PBX-E and Chinese PBX-C) were compared. And it provides a way for the optimization of material performance in engineering production.Finally, in order to make the Drucker-Prager criterion better correspond to the failure envelope force space surface of PBX material. The Drucker-Prager criterion is modified. A step by step from the traditional Drucker-Prager criterion to the linear Drucker-Prager criterion, and then to the hyperbolic Drucker-Prager criterion, and then to the Lublinear yield criterion, finally proposed an adaptive criterion combination advantages of hyperbolic Drucker-Prager criterion and Lublinear yield criterion.