Overturning of multiple-block stacks - Dynamic sensitivity parameters and scaling effect

Both experimental and computational dynamic sensitivity study of multiple-block stacks subjected to a double pulse base excitation are examined. Series of test experiments was conducted at the Oxford Impact Engineering Laboratory on a bespoke platform for a controlled double (initial and reverse) pulse base excitation history. For the computational simulations and validation, the base of the block stack was subjected to a constant acceleration of a finite duration until the desired peak-base velocity, corresponding to the measured experimental values, was achieved. Different overturning modes (forward, backward, global and partial) in both simulations and experiments were characterised as a function of the peak initial base velocity and the timing of the reverse impulse, controlled by the stop gap distance between the base and the stopper. The influence of the block sample scales has also been examined. The conducted set of validation benchmarks is believed to be valuable for researchers, code developers, safety case engineers and industry regulators.