## 1 Introduction  
Laser Powder Bed Fusion (LPBF), one of a number of additive manufacturing techniques, continues to gain attention in the aerospace, biomedical, military, and automotive industries, to name but a few, and is revolutionizing component designs and production lines. The technology has experienced considerable publicity and growth in the last few years, with many successful insertions for non-mission-critical applications such as in the biomedical sector. To meet the full potential that LPBF has to offer, especially for demanding structural applications such as flight-critical components and armaments, qualification and certification are necessary [1]. Some of the key areas that can be considered in the qualification routes include the development of analytical and numerical models that can be used to tailor the LPBF-produced parts to their mechanical properties and performance based on different internal and external state variables [2, 3]. Data driven approaches can also be used to predict mechanical properties such as the fatigue life and fracture of components [4, 5]. The manufacturing of parts with Ti6 Al4V, an alloy commonly used for structural applications in jet engines and as a material for biomedical implants, has traditionally relied on the forging, casting, and rolling of bulk feedstock materials [6]. This is followed by subsequent machining to final shapes and dimensions [6; 7]. However, the manufacturing of parts with this alloy through these conventional processes is always challenging due to its poor thermal conductivity, reactivity with oxygen, and susceptibility to strain hardening [7; 8]. Besides, the nature of these traditional manufacturing processes leads to wastage of high volumes of material, which increases the cost of production. Compared to other additive manufacturing techniques, LPBF has provided a better alternative in the production of Ti6 Al4V alloys, which accounts for more than 50% of the titanium alloy usage in the market [9; 10; 11]. To expedite the acceptance of LPBF Ti6 Al4V (ELI) for use in demanding structural applications, there is a need to develop numerical models based on the internal microstructural state variables in order to predict the performance of the alloy over a wide range of external state variables. Such models are critical in instances where it is difficult to test the mechanical performance of the parts in their actual environmental conditions, such as for temperature and strain rate. A constitutive model for predicting the mechanical performance of different forms of LPBF Ti6 Al4V (ELI) over a wide spectrum of strain rates and temperatures was developed and validated in the authors' work, which can be found in [PERSON] et al. [3]. The constitutive model was based on microstructural internal state variables. The model took into consideration the meso-deformation of various forms of post-process heat-treated LPBF Ti6 Al4V (ELI) alloy, emphasizing the different sizes of \(\alpha\)-grains and initial dislocation densities in these microstructures. The validated model was further implemented separately in the two ABAQUS/Explicit subroutines: VUMAT and VUHARD, which are useful in modelling the isotropic plasticity of materials. The implementation process and simulation results of single and multiple-element numerical models for testing VUMAT and VUHARD subroutines were reported in the authors' work in reference [12]. The obtained positive test results provided a foundation for simulating more complex numerical models with contact interaction, such as the split Hopkinson pressure bar (SHPB) test and Taylor impact test, that allow for modelling at large magnitudes of strain and strain rates. The finite element modelling of the SHPB test for LPBF Ti6 Al4V (ELI) alloy was carried out, where test samples were modelled using the VUMAT and VUHARD subroutines for this material that were extended in this work, the results of which were reported in reference [2].