Residual stresses play detrimental roles in the mechanical performance of lattice-core sandwich panels (LCSPs) via powder bed fusion (PBF), owing to the laser-induced high-temperature gradients. Thus, it is essential to understand the thermo-mechanical behavior of LCSPs during PBF. However, the relation between process settings and the mechanical response of as-printed LCSPs has not been systematically investigated. In this study, an integrated thermo-mechanical modeling is developed to effectively capture the strut stress and deformation of PBF-built LCSPs. The key advance is that the effective thermo-mechanical field within printed LCSPs is first determined based on the homogenization-based differential quadrature method, where the structure-dependent thermophysical and mechanical properties of lattice cores are considered. The effective displacement is used to directly calculate strut stresses through a de-homogenization process. The accuracy of the predicted results is verified by the comparison with the literature. Furthermore, the effect of process parameters, geometrical dimensions, and strut structures on the thermo-mechanical behavior of pyramidal and vertically reinforced pyramid LCSPs is demonstrated. The results show that the strut stress and vertical warpage increase with the higher energy density, length-to-thickness ratio, and vertical strut addition, while decreasing as the inclined angle and environmental temperature enlarge. These findings can offer a guideline for the high-quality printing of LCSPs with desired mechanical performance and dimensional accuracy.

中文翻译：

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粉末床熔融格子夹芯板的热机械建模

由于激光引起的高温梯度，残余应力对通过粉末床熔合 (PBF) 的晶格芯夹层板 (LCSP) 的机械性能产生不利影响。因此，了解 LCSP 在 PBF 过程中的热机械行为至关重要。然而，工艺设置与打印的 LCSP 机械响应之间的关系尚未得到系统研究。在本研究中，开发了一种集成的热机械模型，以有效捕获 PBF 构建的 LCSP 的支柱应力和变形。关键的进步是，印刷 LCSP 内的有效热机械场首先基于基于均质化的微分求积法确定，其中考虑了晶格核的结构相关热物理和机械性能。有效位移用于通过去均匀化过程直接计算支柱应力。通过与文献的比较验证了预测结果的准确性。此外，还论证了工艺参数、几何尺寸和支柱结构对金字塔形和垂直增强金字塔形 LCSP 热机械行为的影响。结果表明，支柱应力和垂直翘曲随着能量密度、长厚比和垂直支柱添加量的增加而增大，而随着倾斜角度和环境温度的增大而减小。这些发现可以为高质量打印具有所需机械性能和尺寸精度的 LCSP 提供指导。