Macro And Micro Simulation Of PBXs’ Response Under Impact

In this paper, ANSYS/LS-DNYA software was used to simulate the deformation,damage and failure process of polymer-bonded explosives (PBXs) under low velocityimpact at macro and microstructural level. The main work of this paper is:1、The calculation model of the drop hammer experiment and Hopkinson experimentwere established. Winfrith constitutive model with damage was used for PBXs to simulatemechanical response such as crack development and damage under low velocity impact.Calculation results were in good agreement with experimental results. PBXs are damagedmainly because of shear and tensile failure.2、The effect of strain rate, the punch shape and aspect ratio on deformation field,stress field and damage of PBXs were studied. The damage degree increases linearly withthe increase of strain rate, then unchanges. The damage of PBXs is caused by shear andtensile failure under flat punch, and PBXs’ damage is caused by tensile failure when thepunch is round head or sharp head. PBXs are prone to damage by shear and tensile failurewhen the aspect ratio is bigger.3、The micro-scale random circular model was established by random distributionprogram, and the real microstructural model based on the digitized micrographs of PBXswas set up. Node separation method was used to simulate the deformation, failure processand the mechanical response of PBXs under dynamic tension and compression. Thestress-strain curve, effective elastic modulus, failure stress and failure strain were obtained.The validity of the model was verified as simulation results were in good agreement withthe experimental results. The results show that the effective elastic modulus and the failurestress of PBXs increase with the volume fraction of explosive particles, and failure straindecreases with the volume fraction. An obvious tension and compression asymmetry can beobtained.