PSI - Issue 31

Alok Gupta et al. / Procedia Structural Integrity 31 (2021) 15–21 Alok Gupta et al. / Structural Integrity Procedia 00 (2019) 000–000

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Additionally, the fracture mechanics based approaches which consider the effect of small and long cracks needs to be developed to confidently predict the effect of anomalies, which are inherent features of the SLM process, on the fatigue life of SLM parts [Gupta et al. (2020)]. Jones et al. (2020) and Gupta et al. (2020) have proposed some effective analytical models to predict the crack growth life of small cracks in AM Ti-6Al-4V alloy. Bracket strength under low cycle fatigue loading and its performance at elevated temperature are to be explored as part of the future research. 4. Conclusions The fatigue performance of a SLM Ti-6Al-4V bracket was studied through shaker table tests. The key findings from this study are summarized as below:  The fundamental vibration mode at 84 Hz is far away from the 1 st LP shaft speed (48 Hz) of the target engine. This demonstrates that the SLM bracket will not experience resonance during engine operation.  The fatigue performance of the SLM bracket is higher than the target ‘20g’ load capability.  The weight optimised ‘struts & connectors’ SLM bracket in Ti-6Al-4V was demonstrated to have the required redundancy in the structural load path.  The crack initiation was from the LOF void and its associated micro-cracks. The build parameters need to be optimized to minimize voids and pores. Acknowledgements We thank Rolls-Royce plc and the EPSRC for the support under the Prosperity Partnership Grant \ Cornerstone: Mechanical Engineering Science to Enable Aero Propulsion Futures, Grant Ref: EP/R004951/1. Also our sincere thanks to Mr. Daniel Cousins (Rolls-Royce Plc.) for his contribution on the development of bracket design. References Gupta, A., Bennett, C. J., & Sun, W, 2021. The role of defects and characterisation of tensile behaviour of EBM additive manufactured Ti-6Al 4V : An experimental study at elevated temperature. Engineering Failure Analysis 120. https://doi.org/10.1016/j.engfailanal.2020.105115 Baragetti, S., Borzini, E., Božić, & Arcieri, E. V., 2019. Fracture surfaces of Ti-6Al-4V specimens under quasi-static loading in inert and aggressive environments. Engineering Failure Analysis 103(April), 132–143. https://doi.org/10.1016/j.engfailanal.2019.04.072. Gorelik, M., 2017. Additive manufacturing in the context of structural integrity. International Journal of Fatigue 94, 168–177. https://doi.org/10.1016/j.ijfatigue.2016.07.005. European Union Aviation Safety Agency: Certification specifications and acceptable means of compliance for engines CS-E, Amendment 5, 2018. Brusa, E., Sesana, R., & Ossola, E., 2017. Numerical modeling and testing of mechanical behavior of AM titanium alloy bracket for aerospace applications. Procedia Structural Integrity 5, 753–760. https://doi.org/10.1016/j.prostr.2017.07.166. Leuders, S., Meiners, S., Wu, L., Taube, A., Tröster, T., & Niendorf, T., 2017. Structural components manufactured by selective laser melting and investment casting - Impact of the process route on the damage mechanism under cyclic loading. Journal of Materials Processing Technology 248(May), 130–142. https://doi.org/10.1016/j.jmatprotec.2017.04.026. Mardaras, J., Emile, P., & Santgerma, A., 2017. Airbus approach for F&DT stress justification of additive manufacturing parts. Procedia Structural Integrity 7, 109–115. https://doi.org/10.1016/j.prostr.2017.11.067. MMPDS-15, 2020a. Chapter 5, Titanium. Metallic Materials Properties Development and Standardization, Federal Aviation Administration: Battelle Memorial Institute. MMPDS-15, 2020b. Chapter 3, Aluminium. Metallic Materials Properties Development and Standardization, Federal Aviation Administration: Battelle Memorial Institute. ASTM B348/B348M – 19, 2019. Standard specification for titanium and titanium alloy bars and billets. Standard, ASTM International, 1–9. https://doi.org/10.1520/B0348_B0348M-19. Gupta, A., Sun, W., & Bennett, C. J., 2020. Simulation of fatigue small crack growth in additive manufactured Ti–6Al–4V material. Continuum Mechanics and Thermodynamics 32(6), 1745–1761. https://doi.org/10.1007/s00161-020-00878-0. Jones, R., Molaei, R., Fatemi, A., Peng, D., & Phan, N., 2020. 1 st Virtual European Conference on Fracture. A note on computing the growth of small cracks in AM Ti-6Al-4V. Procedia Structural Integrity 28, 364–369. https://doi.org/10.1016/j.prostr.2020.10.043.