Stability of tungsten projectiles penetrating adobe masonry – Combined experimental and numerical analysis

•We apply a hydrocode model for adobe to the analysis of penetration experiments.•Differently shaped tungsten-heavy-alloy projectiles are considered.•An experimental database from prior work is revisited and discussed.•The conditions for instability of the penetration in adobe are identified.•We relate this instability to residual velocities and projectile failure. We investigate the penetration of tungsten-heavy-alloy projectiles into adobe targets. The analysis rests on two complementary parts. Firstly, experimental data comprising impact experiments with five different projectile variants against finite-thickness adobe targets is available. Although the data stems from earlier work, it is presented in full detail here for the first time. The general phenomenology is discussed mainly with respect to projectile failure and stability of the penetration in adobe. Secondly, a recently published hydrocode model for adobe under impact loading is applied without further modification for complementing the experimental results with additional time-resolved insight into the penetration mechanics. For the regime without projectile failure or significant plastic deformation, this hydrocode model is capable of reproducing the experimentally observed projectile-target interaction with good overall agreement between experiments and simulation. While the test data covers different penetration regimes from rigid-body motion to projectile failure, the numerical analysis is restricted to linear-elastic behavior of the impactors, in order to avoid any ambiguity due to the less established projectile material description. With the information from the hydrocode simulations, we are able to reveal the origin of the projectile-specific magnitude of instability in the penetration in adobe. The thereby achieved understanding of the motion of the differently shaped impactors within the formed cavity allows us to discuss possible explanations for the particular projectile failure observed in the experimental data.