We report on the results of dimensional analyses on the dynamic plastic
response of square armour steel plates due to detonation of proximal
cylindrical charges and ensued air blast loading. By assuming a generic
function for the blast load, which is multiplicative comprising its spatial and
temporal parts, a set of 14 dimensionless parameters, representative of the
load and plate deformation, were identified and recast in the form of
dimensionless functions of stand-off to charge diameter ratio. Parametric
studies were performed using commercial code ABAQUS’s module of Finite
Element hydrocode using MMALE and MMAE techniques, and combined
with regression analyses to quantify the dimensional parameters and the
expressions for dimensionless functions. A few numerical studies with
various FE mesh types were also performed to validate the transient
deflections against the small-scale experiments. For pulse loading due to
proximal charges of small orders of stand-off/charge diameter ratio, the
magnitude of the transverse deflection increased abruptly with incremental
decrease in stand-off, in contradistinction to the plate deformations at
higher stand-offs where variations in displacement are smooth. This
confirmed the existence of a stand-off at which a transition in behaviour
takes place. For stand-off values less than charge diameter, a dimensionless
energy absorbing effectiveness factor was considered to investigate the
prediction of rupture in the plate corresponding to different charge masses.
This factor is measured as a baseline parameter to predict, using solely
numerical means, the blast loads which ensue rupture on full-scale
prototypes.