Computer-simulations based development of a high strain-rate, large-deformation, high-pressure material model for STANAG 4569 sandy gravel

The NATO Standard Agreement [STANAG 4569, Protection for occupants of logistics and light-armored vehicles] defines the make-up and the conditions of sandy-gravel soil which is used for testing the ability of various armor systems to provide the necessary level of protection. In this paper, an effort is made to develop a high strain-rate, large-strain, high-pressure material model for sandy gravel which can be used in transient non-linear dynamic simulations of the interactions between landmine detonation gaseous products, landmine-casing fragments and soil ejecta and the target military vehicles. The material model for sandy gravel has been developed by extending the CU–ARL sand model [Grujicic M, Pandurangan B, Cheeseman BA, Roy WN, Skaggs RR, Gupta R. Parameterization of the porous-material model for sand with various degrees of water saturation. Soil Dyn Earthquake Eng 2008;28(1):20–35] in order to include the effects of gravel particles on the equation of state, strength, failure and erosion behavior. Parameterization of the sandy gravel soil model has been done by carrying out a series of computational experiments pertaining to the deformation and fracture behavior of the two-phase (sand plus gravel) material. Experimental tests which should be carried out in order to validate the proposed model have been identified and described.