Abstract Scope |
Most of the existing manufacturing quality acceptance criteria stipulated in various Codes and Standards or recommended practices are empirical in nature. These workmanship-based criteria have been shown adequate historically for quality control purposes in construction of metallic structures. However, as additive manufacturing (AM) is being rapidly adopted for cost-effectively fabricating critical metallic parts for safety-critical components subjected to fatigue loading, one of the major challenges has been on how to address structural significance of spatially distributed geometric discontinuities. In this talk, some of the recent developments in fracture mechanics based discontinuity acceptance criteria will be first highlighted. Interestingly, there exists a great deal of similarity between AM and welded components as far fatigue behaviors are concerned. Such an important observations will then be substantiated through synthesis of a number of detailed studies on AM parts made of stainless steel, Inconel 718, Ti-6-4, and aluminum alloys through different AM processes and post-AM processing techniques. Finally, the resulting key findings on fitness-for-purpose based discontinuity acceptance criteria will demonstrated on a few selected engineering components, including their NDT-based implementation in practice. |