ABSTRACT
Fully coupled numerical modelling of large complex structures subjected to blast loads is computationally expensive. To reduce costs, uncoupled analyses are pursued wherever feasible, although this may lead to less realistic results since shock-structure interaction (SSI) effects are not captured. Consequently, a method is sought to assess the significance of SSI effects prior to undertaking a fully coupled analysis. This paper presents simple 1D numerical and approximate closed form solutions for the classical problem of a plane shock in air impinging on a free plate. The numerical solution is validated using published experimental data, while the approximate analyses provide upper and lower bounds to the decrease in reflected shock pressure due to SSI effects. A dimensionless number is proposed that provides a first order upper estimate for the plate velocity deviation due to SSI effects. In conjunction with an uncoupled blast analysis, this number is convenient for assessing whether a fully coupled blast analysis is required.
