CAREER: A Predictive Modeling and Simulation-Based Certification Framework for Additive Manufacturing of Metals

该学院早期职业发展（Career）项目研究项目将专注于推导一种高效的基于科学的策略——将预测建模和模拟与最佳实验选择相结合——由严格的不确定性量化方法驱动，以加速粉末床熔融金属增材制造的认证。基于粉末床融合的增材制造技术是所有增材制造技术中最通用和商业化的技术之一，用于制造金属部件。它可以实现高度的设计自由度，开发新颖的材料结构，并以合理的成本制造定制产品。粉末床熔炼需要使用高功率能量束熔化粉末颗粒，并将它们一层又一层融合在一起，形成所需的形状。颗粒所经历的复杂热历史通常会导致制造材料中形成更多的缺陷，显著的应力和变形以及裂纹。该研究项目将开发基于粉末床融合的增材制造过程的建模和计算能力，并了解加工参数与材料微观结构中缺陷形成之间的基本关系，以制造更好的金属产品。该研究还将通过建立一个响应迅速、灵活的教育和外展计划来补充，该计划基于课程开发、增材制造工作室的培训演示以及通过机构STEM教育中心进行的K-12和代表性不足的少数民族外展。研究的具体目标是发现粉末床熔融金属增材制造的工艺-显微组织-性能关系。众所周知，熔池动力学控制着印刷金属微观结构中的缺陷形成，并决定了制造零件的质量。S的宏观性质和性能。因此，本项目的研究目标包括：(i)开发基于高性能计算的强热-机-流-固耦合问题数值求解器；（ii）对粉末床熔融过程进行直接数值模拟的能力；（iii）基于模型的不确定度量化和打印金属的认证。将回答以下基本问题：(1)在严酷的热力载荷条件下，粉末床的热力学响应是什么；(2)工艺参数和粉末特性在制备材料微观结构演变中的作用。总体重点将是更好地了解缺陷形成和演变的物理，包括：孔隙率，未熔化颗粒，晶界和微裂纹，在粉末床熔合过程中。该项目将使PI在计算科学，力学和材料科学方面的知识基础得到提升，并在先进制造领域建立长期的职业生涯。

This Faculty Early Career Development (CAREER) program research project will focus on deriving a highly effective science based strategy --combing predictive modeling and simulations with optimal experimental selection-- driven by a rigorous uncertainty quantification methodology for accelerated certification of powder bed fusion based additive manufacturing of metals. Powder bed fusion based additive manufacturing technology is one of the most versatile and commercialized advances of all additive manufacturing techniques for the fabrication of metallic components. It enables a high degree of design freedom, development of novel material structures, and manufacture of customized products at reasonable costs. Powder bed fusion requires the use of high power energy beams to melt the powder particles and fuse them together layer after layer to form the desired shape. The complex thermal history experienced by the particles usually causes the formation of more defects, significant stresses and distortion as well as cracks in the fabricated materials. This research project will develop modeling and computational capabilities for the analysis of powder bed fusion based additive manufacturing processes and to understand the fundamental relationship between the processing parameters and the defect formation in the materials microstructure, to fabricate better metallic products. The research will also be complemented by establishing a responsive and flexible educational and outreach program based on curriculum development, training demonstrations in an additive manufacturing studio, and K-12 and underrepresented minority outreach through an institutional STEM education center.The specific goal of the research is to discover the process-microstructure-property relationship for powder bed fusion based additive manufacturing of metals. It is an established fact that the melt pool dynamics governs the defect formation in the microstructure of printed metals and determines the fabricated part?s macroscopic properties and performance. Thus, the research objectives of this project include: (i) development of a high performance computing based numerical solver for strong thermomechanical and fluid-structure coupled problems; (ii) capability to perform direct numerical simulation of powder bed fusion processes; (iii) model-based uncertainty quantification and certification of printed metals. The following fundamental questions will be answered: (1) what is the thermodynamic response of the powder bed under severe thermomechanical loading conditions; (2) what are the roles of processing parameters and powder characteristics in the microstructure evolution of fabricated materials. The overarching focus will be on obtaining a better understanding of the physics of defect formation and evolution, including: porosity, unmelted particles, grain boundaries and micro-cracks, during the powder bed fusion processes. This project will allow the PI to advance the knowledge base in computational science, mechanics and material science, and establish his long-term career in advanced manufacturing.