The effect of the bend radius on the impulse transfer characteristics of V-hulls: Numerical simulations. Issue 1 (March 2020) - Langdon, Genevieve Sarah
A study was performed to investigate the effects of geometry on impulse transfer to V-plates subjected to localised air-blast loading. The V-plates were designed to be 1:8 scale compared to the full-scale V-hulls used in landmine-protected vehicles. Simulations were performed using LS-DYNA and validated using results from blast experiments on scaled rigid V-plated structures of varying internal angle. The validated numerical models were then used to ascertain the influence of including the clamp, varying the stand-off distance, internal angle and V-tip radius on impulse transfer. The simulations showed that, in general, the impulse increased as V-tip radius increased. For the 90° and 120° V-plates, the impulse transferred was observed to plateau for bend radii greater than 160 mm. The increase in impulse was attributed to changes in the spatial and temporal load distribution due to the higher V-tip radius. There was no significant variation in the pressure distributions for larger bend radii (above 160 mm). For both the 90° and 120° V-plates, a dip in impulse was observed when the V-tip radii was between 0 and 20 mm. This was caused by reduced peak pressures and an increase in gas flow. Fixing the clearance height and increasing the V-tip radius (and therefore the stand-off distance) had no discernible effect on impulse transfer. However, it was shown to increase the arrival time and load duration, while decreasing the peak total force.