To address the intense heat and electromagnetic loads that occur during a disruption, a shattered pellet injection (SPI) system will be employed at ITER [1]. The penetration and assimilation of the injected material is influenced by various SPI parameters, including the fragment sizes, speeds, and composition of the shattered fragments. A flexible SPI system was installed on the ASDEX Upgrade tokamak [2] to study the effect of the aforementioned parameters. In this presentation, 1.5D simulations with the INDEX [3] code have been utilised to conduct parametric scans of SPI parameters for standard AUG H-mode discharges, thus examining the influence of fragment size, speed and pellet composition on the efficacy of disruption mitigation. Comparisons of simulation results of material penetration and assimilation are carried out with the experimental measurements. For mixed deuterium-neon injections, larger and faster fragments enabled higher assimilation, in agreement with the experiments. In the simulations, the amount of assimilated neon increased with increasing injected neon amounts but saturated for larger neon fraction pellets. For pure deuterium injections, simulations exhibit larger and faster fragments leading to greater penetration, aligning with findings from the experiments. References: 1. Lehnen, M., et al 29th IAEA Fusion Energy Conference (FEC) 2023 2. M. Dibon et al., Reviev of Scientific Instruments 94 043504, 2023. 3. A Matsuyama et al 2022 Plasma Phys. Control. Fusion 64 105018