Failure analysis of a landing gear nose wheel fork produced in Ti6Al4V(ELI) through selective laser melting

This paper presents the failure analysis of a topologically optimised landing gear nose wheel fork of a light aircraft that was produced in Ti6Al4V(ELI) through selective laser melting (SLM). The study was motivated by the intention of the South African producer of the Advanced High-Performance Reconnaissance Light Aircraft (AHRLAC) to consider replacing conventional manufacturing of some structural components with additive manufacturing (AM). However, the defects typically associated with AM, such as inherent surface roughness and porosity, still complicate the certification of AM parts due to their detrimental effects on fatigue performance. An experimentally validated numerical simulation, fractographic analysis and microscopic investigation were carried out on a scaled-down Ti6Al4V(ELI) component to devise preventative actions to avoid failure of the full-scale fork. The mass saving, strength and fatigue limitations of the actual nose wheel fork of the AHRLAC are discussed. This study also outlines an effective failure analysis and data collection method necessary to qualify SLM of Ti6Al4V(ELI) to produce other airworthy mission-critical structural aircraft components.