Fragmentation occurs in structures when subjected to large-strain-rate loading that commonly occurs in ballistic and asteroid impacts. In ductile materials, fragmentation is preceded by localized plastic deformation forming multiple adiabatic shear-bands. The shear-band-spacing thus formed controls the final fragment-size distribution. The observed fragment-size distribution is different from the theoretically predicted values. The above discrepancy can be deciphered by simulating multiple-shear-band formation that accounts for both thermal- and shear-void-growth-softening (which is often ignored). We model the shear-void-growth-softening by using the extended Gurson-model Nahshon-Hutchinson model)) in our method of characteristics-based finite-difference solution methodology. We perform parametric simulations varying the shear-void-growth-rate. Our results indicate that the number of shear-bands increases linearly with increase in the shear-void-growth-rate for any applied strain-rate. The average shear-band-spacing thus predicted is reduced, signifying the important role of shear-void-growth-softening in the simulations of multiple-shear-band formation.
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