Offering the possibility of producing complex geometries in a compressed product development cycle, it comes as no surprise that Additive Manufacturing (AM) techniques have become attractive to multiple industries, including the automotive and aerospace segments. Unfortunately, the ubiquitous stratified build approach used by these technologies is responsible for the pain point that hinders their adoption in production of parts that will be subjected to complex loads: the junction of adjacent layers tends to have subpar mechanical properties when compared to those of the bulk material, and thus, assessing the structural integrity of an AM part becomes difficult. In the advent of the industrialization of series production of AM parts for the automotive industry, the necessity to understand and predict how and why AM parts fail under complex stress states becomes of paramount importance. This paper applies a failure criterion for materials with anisotropic properties with stress interactions, to predict failure of multi-jet fusion (MJF) parts manufactured using polyamide 12 powder. The results are compared to the failure surfaces of Selective Laser Sintering (SLS) components. Special test specimens were designed, produced, and tested to measure failure under tensile, compressive, shear, and combined loading scenarios. The results show that much like SLS, MJF parts have a notable difference in tensile and compressive strengths. Unlike SLS however, MJF parts do not exhibit a strong interaction between stresses when under combined loading. The experimental data shows an excellent fit with the failure criterion, precisely capturing the strength behavior of MJF printed parts under complex loading conditions. Of great interest in this study is that the stress interactions with MJF parts were determined to be negligible when compared to SLS specimens, which emphasizes the fact that when performing stress analyses, each one of these powder-based additive manufacturing techniques must be treated differently.

由于可以在压缩的产品开发周期中生产出复杂的几何形状，因此增材制造（AM）技术对包括汽车和航空航天领域在内的多个行业的吸引力就不足为奇了。不幸的是，这些技术使用的无处不在的分层构建方法导致了痛苦点，这些痛苦点阻碍了它们在承受复杂载荷的零件的生产中的采用：与之相比，相邻层的接合处往往具有较差的机械性能。大块材料，因此，评估AM零件的结构完整性变得困难。随着汽车工业AM零件的批量生产产业化的到来，理解和预测AM零件在复杂应力状态下如何以及为何失效的必要性变得至关重要。本文对具有各向异性的具有应力相互作用的材料应用了失效准则，以预测使用聚酰胺12粉末制造的多喷射融合（MJF）零件的失效。将结果与选择性激光烧结（SLS）组件的失效表面进行比较。设计，生产和测试特殊的试样，以测量在拉伸，压缩，剪切和组合载荷情况下的破坏。结果表明，与SLS一样，MJF零件的拉伸强度和压缩强度也有明显差异。但是，与SLS不同，MJF零件在组合载荷下不会在应力之间表现出强烈的相互作用。实验数据显示出与破坏准则的极佳契合度，可精确捕获在复杂载荷条件下MJF印刷部件的强度行为。在这项研究中引起极大兴趣的是，与SLS试样相比，与MJF零件的应力相互作用可忽略不计，这强调了一个事实，即在进行应力分析时，这些基于粉末的增材制造技术中的每一种都必须区别对待。