Residual stress and plastic strain in additive manufactured materials can exhibit significant microscopic variation at the powder scale, profoundly influencing the overall properties of printed components. This variation depends on processing parameters and stems from multiple factors, including differences in powder bed morphology, non-uniform thermo-structural profiles, and inter-layer fusion. In this research, we propose a powder-resolved multilayer multiphysics simulation scheme tailored for porous materials through the process of selective laser sintering. This approach seamlessly integrates finite element method (FEM) based non-isothermal phase-field simulation with thermo-elasto-plastic simulation, incorporating temperature- and phase-dependent material properties. The outcome of this investigation includes a detailed depiction of the mesoscopic evolution of stress and plastic strain within a transient thermo-structure, evaluated across a spectrum of beam power and scan speed parameters. Simulation results further reveal the underlying mechanisms. For instance, stress concentration primarily occurs at the necking region of partially melted particles and the junctions between different layers, resulting in the accumulation of plastic strain and residual stress, ultimately leading to structural distortion in the materials. Based on the simulation data, phenomenological relation regarding porosity/densification control by the beam energy input was examined along with the comparison to experimental results. Regression models were also proposed to describe the dependency of the residual stress and the plastic strain on the beam energy input.

增材制造材料中的残余应力和塑性应变可能会在粉末尺度上表现出显着的微观变化，从而深刻影响打印部件的整体性能。这种变化取决于加工参数并源于多种因素，包括粉末床形态的差异、不均匀的热结构分布和层间熔合。在这项研究中，我们提出了一种通过选择性激光烧结过程为多孔材料量身定制的粉末解析多层多物理场模拟方案。该方法将基于有限元法 (FEM) 的非等温相场仿真与热弹塑性仿真无缝集成，并结合了与温度和相位相关的材料特性。这项研究的结果包括对瞬态热结构内应力和塑性应变的细观演化的详细描述，并通过一系列光束功率和扫描速度参数进行评估。模拟结果进一步揭示了潜在的机制。例如，应力集中主要发生在部分熔化颗粒的颈缩区域和不同层之间的连接处，导致塑性应变和残余应力的积累，最终导致材料的结构变形。基于模拟数据，研究了通过束能量输入控制孔隙率/致密化的唯象关系，并与实验结果进行比较。还提出了回归模型来描述残余应力和塑性应变对梁能量输入的依赖性。