Probing The Impact Release Behaviour Of Al/Ni-based Energetic Structural Materials Adopting Experimental And Numerical Method

In the past four decades,with the emergence and development of efficienct damage warhead technology,the concept of reactive fragment has also been proposed,which is a new type of warhead damage element combining with releasing energy properties caused by impacting and penetrating characteristics similar to those of insensitive fragment.The preparation materials of reactive fragment are called energetic structural materials?ESMs?,which are also used in the field of reactive armor.As a new type of material,it is significantly to accurately grasp the mechanical and impact release chemical characteristics,contributing to enhance the power of the warhead and expand the application fields of ESMs.The paper has conducted a series of studies adopting a method combining with theoretical calculations,experiments and numerical simulations.The simulations,considering mechanical-thermo-chemical coupling effect,of impact release energy behaviour of Al/Ni-based ESMs,including Al-Ni,Al-Ni-CuO and Al-Ni-MoO₃,have been implemented,which are prepared by compression-sintering technique.At first,compressive mechanical properties of ESMs were characterized with material testing machine and the split Hopkinson pressure bars?SHPB?.The parameters of Johnson-Cook constitutive model of three materials were fitted on the basis of experimental data.Then the microscopic metallographic structures of the samples before and after the experiments were observed by optical microscope?OM?.Secondly,since the Al/Ni-based ESMs can be regarded as porous mixtures with high mass-fraction,the Hugoniot data of ESMs were calculated adopting cold-energy superposition theory and Wu-Jing method under medium and low pressure compression loading condition.Thirdly,direct ballistic tests were applied to investigate the characterization of impact release energy behaviour of Al/Ni-based ESMs.According to the experimental data,shock temperatures under various impact velocities were calculated on the basis of existing shock-induced chemical reaction thermo-chemical model considering chemical reaction efficiency.The parameters of chemical reaction kinetics were fitted based on the functional relationship between shock temperature and the extent of reaction measured in the direct ballistic tests.Finally,based on the secondary development interface of LS-DYNA software,a coupled mechanical-thermo-chemical constitutive model was developed on the basis of a user-defined Johnson-Cook model.The validity was verified by the comparison between numerical simulation results and the experimental results.The research conclusionsin this paper can provide support for the design of warhead structure with reactive damage fragments made by ESMs,and offer a reference for the numerical simulation mehod of ESMs in the materials and weapons engineering field.There are important practical significance and application value for guiding the further development of high efficiency damage warhead technology and improving weapons and ammunition damage ability.