ideal rigid-plastic slab, rectangular slab, round aperture, explosive load, permanent deflection.

The method of calculation at ultimate load and permanent deflection of rectangular slabs with a free round aperture under the impact of uniformly distributed dynamic load of explosive type on the basis of ideal rigid-plastic material model is proposed. The slab sides are simply supported and fixed. Possible schemes of slab ultimate deforming are described. Numerical examples are given. The solutions can be used in various engineering calculations.