Investigation on mechanical properties of Ti-6Al-4 V multilayer micro-lattice biomaterials under dynamic compression loading

Abstract

Novel skull repair Ti-6Al-4 V multilayer micro-lattice biomaterials (MMBs) proposed recently have promising application in clinical practice. Herein, the dynamic compression performances of MMBs are concerned and investigated by Split Hopkinson Pressure Bar (SHPB) system and finite element (FE) methods. Typical shear band, strut yielding and damage deformation modes of MMBs are characterized by FE and SHPB experiment. Through density gradient regulation, deformation mode of MMBs is transformed from shear band to localized collapse pattern. It is interesting that MMBs with different unit cell sizes exhibit different strain rate sensitivities. For strain rate-insensitive MMBs (BCC(3), BCC(5) and BCCZ(3)), the influence of relative density on strength shows a linear increasing trend under both low and high strain rates. For strain rate-sensitive ones (BCC(7), BCCZ(5) and BCCZ(7)), the influence of relative density on strength under low strain rate is stronger than that under high strain rate. The strength range of MMBs matches skull/bone materials well under same loading strain rate. This work not only reveals dynamic mechanical properties of MMBs but also has enlightenment for investigating dynamic properties of porous metamaterials.