Iliopoulos Athanasios P, Jones Rhys, Michopoulos John G, Phan Nam, Rans Calvin
Computational Multiphysics Systems Laboratory, Center for Materials Physics and Technology, US Naval Research Laboratory, Washington, DC 20375, USA.
Centre of Expertise for Structural Mechanics, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
Materials (Basel). 2020 May 12;13(10):2223. doi: 10.3390/ma13102223.
Understanding and characterizing crack growth is central to meeting the damage tolerance and durability requirements delineated in USAF Structures Bulletin EZ-SB-19-01 for the utilization of additive manufacturing (AM) in the sustainment of aging aircraft. In this context, the present paper discusses the effect of different AM processes, different build directions, and the variability in the crack growth rates related to AM Ti-6Al-4V, AM Inconel 625, and AM 17-4 PH stainless steel. This study reveals that crack growth in these three AM materials can be captured using the Hartman-Schijve crack growth equation and that the variability in the various versus curves can be modeled by allowing the terms Δ and to vary. It is also shown that for the AM Ti-6AL-4V processes considered, the variability in the cyclic fracture toughness appears to be greatest for specimens manufactured using selective layer melting (SLM).
理解和表征裂纹扩展对于满足美国空军结构公告EZ-SB-19-01中所规定的在老旧飞机维修中使用增材制造（AM）的损伤容限和耐久性要求至关重要。在此背景下，本文讨论了不同增材制造工艺、不同构建方向以及与增材制造Ti-6Al-4V、增材制造Inconel 625和增材制造17-4 PH不锈钢相关的裂纹扩展速率变异性的影响。本研究表明，这三种增材制造材料中的裂纹扩展可以使用Hartman-Schijve裂纹扩展方程来捕捉，并且通过允许Δ和项变化，可以对各种与曲线的变异性进行建模。研究还表明，对于所考虑的增材制造Ti-6AL-4V工艺，使用选择性层熔化（SLM）制造的试样，其循环断裂韧性的变异性似乎最大。
