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The determination of the blast protection level of laminated glass windows and facades is of crucial importance, and it is normally done by using experimental investigations. In recent years numerical methods have become much more powerful also with respect to this kind of application. This paper attempts to give a first idea of a possible standardization concerning such numerical simulations. Attention is drawn to the representation of the blast loading and to the proper description of the behaviour of the material of the mentioned products, to the geometrical meshing, and to the modelling of the connections of the glass components to the main structure. The need to validate the numerical models against reliable experimental data, some of which are indicated, is underlined.

A special phenomenon observed in hypervelocity impacts on rock targets is the so-called momentum multiplication, i.e. the momentum transferred to the target is greater than the original momentum of the projectile. This effect is caused by ejection of debris in the direction opposite to the flight direction of the projectile. In the present study momentum multiplication was investigated as a function of target material properties and projectile velocity. Hypervelocity impact experiments on target materials with different porosities were conducted and the momentum transfer was measured using a ballistic pendulum. Low porous materials like quartzite show larger momentum multiplication than porous materials like sandstone. The smallest momentum multiplication was measured for highly porous aerated concrete. Higher projectile velocity leads to higher momentum multiplication. Furthermore, this increase is stronger for low porous materials compared with porous materials. These observations can be explained by the different ejection behavior. Low porous materials show a directional and very fast ejection whereas porous materials show a slower ejection. The highly porous material shows a diffuse ejection behavior. Furthermore, cratering efficiency is reduced in porous targets leading to a smaller amount of ejected debris. This effect is attributed to energy dissipation caused by irreversible crushing of pore space.

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