An investigation of shear thickening fluids using ejecta analysis techniques

• We investigate the ejecta from projectile impacts on shear thickening fluids (STFs).
• A lateral-axial kinetic energy ratio (α) is used to compare the ejecta fields.
• A computational model relates α to intergranular friction and particle stiffness.
• Trends in the α ratio are related to interparticle friction within the STFs.

In the present study, ejecta dynamics techniques are used to investigate the ballistic response of shear thickening particle suspensions as a means of assessing the particle hardness and the role of interparticle friction during penetration. Through particle material variations, the role of particle material strength is discussed primarily through the ratio of the total lateral to total axial kinetic energy of the ejecta field at increasing impact velocities. Two dominant trends are observed in the relation between this ratio of kinetic energy and impact velocity, which are attributed to the properties of the suspended particles. A qualitative model of particle fracture and deformation is proposed to account for the experimental observations. The results of analytical particle strain estimates and computational discrete element modelling of impact ejecta are used to inform the model and discuss the role of interparticle friction in the ejecta field.