PSI - Issue 46

Raviraj Verma et al. / Procedia Structural Integrity 46 (2023) 175–181 Raviraj Verma/ Structural Integrity Procedia 00 (2021) 000–000

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1. Introduction Titanium alloys have been used as a space-age metallic alloy since 1950 and started gaining more attention in industry 4.0 revolution (Company 2000) due to its unique tensile, fracture toughness and high-temperature properties. Additive manufacturing technology is propelling the rapid development of aerospace, aeronautical and biomedical components with several advantages such as freedom to design-flexibility, near-net-shape design, low buy-to-fly ratio, and improved quality re-usability, reduced environmental footprint, etc (Donachie 2000). One of the laser-based powder bed fusion techniques, laser powder bed fusion (LPBF) has efficiently been used to print highly precise parts subjected to minimal post-processing for its direct applications. Along with LPBF, several laser- and directed energy based additive manufacturing techniques such as EBM and DMLS are Laser sourced and LENS and EBF as directed energy sourced (Lewandowski and Seifi 2016) are used extensively for the fabrication of complex parts. The LPBFed Ti alloys are highly useful to design various components with less materials waste and machining cost, which makes it overcome a lot of materials’ wastages as experienced in conventional processing of expensive Ti alloys. The AMed Ti alloys exhibit various types of microstructures which influence mechanical properties significantly. These microstructures are purely governed by additive process parameters such as scan speed, deposition rate, energy source power, hatch spacing, etc (Shipley et al. 2018). The experimental cost associated with the structure-property correlation studies is very high due to the fast depleting resources of materials and therefore, computational methods are becoming inexpensive tools to predict the deformation characteristics and thereby performance and life of materials under actual service conditions. There are several computational techniques such as finite element methods (FEM) (Alshoaibi and Fageehi 2021; Upadhyay, Sonigra, and Daxini 2021), extended finite element methods (XFEM) (Kumar, Pathak, and Singh 2021; Kumar and Singh 2019), extended isogeometric analysis (XIGA) (Singh et al. 2019), element free galerkin methods (EFGM) (Rohit, Prajapati, and Patel 2020), etc available in the literature to predict life of materials subjected to static and dynamic loads. Discontinuities such as cracks or defects in materials are well captured through XFEM approach which helps to understand crack initiation, propagation, the effect of crack size location in the computational domain efficiently. In the current studies, XFEM was employed to track crack initiation and propagation behaviour to evaluate fracture toughness and stress distribution in LPBFed Ti-6Al-4V alloy at varying loads. Along with fracture toughness and stress distribution, the experimental fatigue data of LPBFed Ti alloy were used to simulate its fatigue life through stress-based criteria adopted in FE-Safe software. 2. Numerical Methods The linear elastic fracture toughness is evaluated as per the ASTM E399 standard guidelines, where provisional fracture toughness ( � ) is estimated through Eq. (1). The evaluated � is validated through stress and dimensional criteria as mentioned through Eqs. (2) and (3) (Verma et al. 2019, 2020; Verma, Nath, and Jayaganthan 2018). � � � � ��� � � � �⁄� .3� � � . ��.���� �� ���� �� ���.����.�� �� ��.�� �� � � �� ����� �� ���� �� � ��� (1)

where,

��������� ��.�� � � � �� � �

(2)

� ��� � � ��.�

(3)