We have performed 3D finite element simulations of collapsing thick-walled cylinders and thin-walled tubes subjected to dynamic twisting in order to investigate the effect of porous microstructure on shear bands formation at high strain rates. The distinctive feature of this work is that we have followed the methodology developed by Marvi-Mashhadi et al. [1] to incorporate into the finite element calculations the actual porous microstructure of four different additively manufactured materials –aluminium alloy AlSi10Mg, stainless steel 316L, titanium alloy Ti6Al4V and Inconel 718– for which the initial void volume fraction varies between 0.001% and 2%, and the pores size ranges from ≈6 μm to ≈110 μm. The mechanical behavior of the material is modeled as elastic-plastic, with yielding described by the von Mises criterion, an associated flow rule and isotropic hardening/softening, being the flow stress dependent on strain, strain rate and temperature. The finite element results show that spatial and size distribution of voids affects the formation and propagation of shear bands. It is observed that the increase of the void volume fraction shows a moderate effect on the shear localization process, the maximum diameter of the pores being the main microstructural feature affecting shear banding nucleation and growth. Thick-walled cylinder collapse simulations show multiple shear bands formation and bring out that for a given void volume fraction more shear bands are nucleated as the number of voids increases, while the shear bands are incepted earlier and develop faster as the size of the pores increases. On the other hand, a single shear band is generally formed in the case of twisting thin-walled tubes, leading to a sudden drop in load carrying capacity, so that it is possible to obtain a master curve which determines the decrease of the sample ductility with the size of the largest pore of the microstructure.