This article proposes a novel high-performance computing approach for the prediction of the temperature field in powder bed fusion (PBF) additive manufacturing processes. In contrast to many existing approaches to part-scale simulations, the underlying computational model consistently resolves physical scan tracks without additional heat source scaling, agglomeration strategies or any other heuristic modeling assumptions. A growing, adaptively refined mesh accurately captures all details of the laser beam motion. Critically, the fine spatial resolution required for resolved scan tracks in combination with the high scan velocities underlying these processes mandates the use of comparatively small time steps to resolve the underlying physics. Explicit time integration schemes are well-suited for this setting, while unconditionally stable implicit time integration schemes are employed for the interlayer cool down phase governed by significantly larger time scales. These two schemes are combined and implemented in an efficient fast operator evaluation framework providing significant performance gains and optimization opportunities. The capabilities of the novel framework are demonstrated through realistic AM examples on the centimeter scale including the first scan-resolved simulation of the entire NIST AM Benchmark cantilever specimen, with a computation time of less than one day. Apart from physical insights gained through these simulation examples, also numerical aspects are thoroughly studied on basis of weak and strong parallel scaling tests. As potential applications, the proposed thermal PBF simulation framework can serve as a basis for microstructure and thermo-mechanical predictions on the part-scale, but also to assess the influence of scan pattern and part geometry on melt pool shape and temperature, which are important indicators for well-known process instabilities.

翻译：本文提出一种新型高性能计算方法，用于预测粉末床熔融（PBF）增材制造工艺中的温度场。与现有多种零件尺度模拟方法不同，该底层计算模型在不借助热源缩放、团簇策略或其它任何启发式建模假设的前提下，可一致地解析物理扫描轨迹。通过动态自适应加密网格精确捕捉激光束运动的所有细节。关键之处在于，为实现扫描轨迹解析所需的精细空间分辨率，结合工艺过程中固有的高扫描速度，必须采用相对较小的时间步长以解析底层物理过程。显式时间积分格式在此场景中表现出显著优势，而针对受控于大得多的时标的层间冷却阶段，则采用无条件稳定的隐式时间积分格式。上述两种格式被有机结合并部署于高效快速算子评估框架中，从而提供显著的性能提升与优化空间。通过厘米级真实增材制造示例（包括首次完成整个NIST AM基准悬臂梁试件扫描解析模拟，计算时间不超过一天），验证了该新型框架的能力。除通过上述模拟示例获得的物理洞察外，还基于弱扩展与强扩展并行测试对数值特性进行了系统研究。在潜在应用方面，所提出的热PBF仿真框架既可作为零件尺度微观结构与热力学预测的基础，也可用于评估扫描路径与零件几何形状对熔池形态及温度的影响——这些参数正是已知工艺不稳定性的重要指标。